GFI Caused a Fire!

[a@b.c]

My neighbor just suffered a serious fire. His house had an enclosed
porch at the rear, with an open, roofed desk connected to the porch
rear. He had several GFI breakers out there, including one on the
rear porch wall. Around one AM, when he and family were asleep,
a fire started at that GFI switch (according to Fire Marshall), and
got going pretty good before their dog started barking. That saved
their lives for sure. Almost killed their dog and cat, though. The
fire badly burned the rear half of the house and sent black soot
throughout the rest of the house. The house is pretty well totaled.

That's what happened. I have to wonder how a GFI could do that!
I heard the Fire Marshall actually say that what happened was the GFI
wires arced, but that was not a 'short' to the GFI. Hence it didn't
trip. So, the GFI presented no protection did it! The arcing just
continued until it started the fire!

All this makes me think that my GFIs are not providing me the
protection I always thought they did. I'm not sleeping as well these
days.

Anyone have an opinion about this?

Thanks

me

[RBM]

GFCI devices don't provide short circuit protection. They provide ground
fault protection. The device that would have, should have prevented this
is the circuit breaker, or better still, an arc fault circuit breaker

[thekma...@gmail.com]

Now the question is, did that GFCI preclude the circuit breaker's ability to do its job?

[Tomsic]

"RBM" <r...@noemail.com> wrote in message
news:51cac78e$0$20234$607e...@cv.net...

Right, the usual GFCI does not against electrical arcs. The National
Electrical Code now requires arc fault circuit interrupters (AFCI) in
certain rooms of homes to reduce such fires. Wikipedia has a good summary
of what GFCIs can and cannot do at:
http://en.wikipedia.org/wiki/Arc-fault_circuit_interrupter Arcing that
results from loose connection at outlets and switches or broken wires are a
major cause of house fires.

Tomsic

[John Grabowski]

*I surmise that the GFI receptacle had loose connections and that there was
a considerable load on the wiring. That would cause the arcing which would
ignite any combustible materials in direct contact or in very close
proximity.

As RBM pointed out the GFI is not designed for this type of protection, but
an arc fault circuit breaker is.

Does this house have smoke detectors?

[bud--]

And if that is what happened the GFCI wasn't any more responsible for
the fire than if the same thing happened with an ordinary receptacle.

I wonder how much of the GFCI was left for the fire marshal to determine
what happened.

[micky]

So it seems like the ground fault is especially useful near water
faucets and wet places.

But the arc fault seems especiallly useful everywhere, not just
bedrooms. Does that mean every circuit breaker should be arc fault?

[DerbyDad03]

Now I'm really going to burst your bubble.

You know all those years you were sleeping well because you thought your GFCI's were protecting you against a short and/or a fire? Well, you shouldn't have been sleeping that well because a GFCI won't do either.

You really should read up on how GFCI's work and what they do and don't protect against so that you are not living under incorrect assumptions.

[a@b.c]

Yes. Though he never mentioned that one went off. Seems like a
detector should have detected all that smoke. Maybe he had
detector(s) in the house proper, but not on the porch enclosure on the
rear. The smoke did not get into the house until he actually opened
from the inside of the house one of the sliders from the house onto
the porch, at which time the sliding doors actually exploded and blew
into the house. At that point the black smoke inundated the house
proper. So I'll bet he had no detector on the porch. I'll have to
ask. Now that I think about that, I don't either. My enclosed sun
porch was built after the house.
As soon as I can, I am going to add one to my porch for sure.

me

[a@b.c]

On Wed, 26 Jun 2013 07:33:57 -0600, bud-- <remove....@isp.com>
wrote:

It was there. I saw it - together with his written report hanging
from it. I saw it too.

me

[recycl...@gmail.com]

1. Did the fire start inside the electrical box of the GFCI or a circuit coming or leaving it?
2. Was the electrical box metal or plastic and was it in a wet location and if so was it an outdoor box?
3. Was the line connected to the box Romex or was it inside a conduit and if it was inside a conduit was it a EMT or rigid or PVC and was it in a wet location?

[John Grabowski]

*Article 210.12 in the 2011 National Electrical Code requires them for
almost every circuit in a home.

[The Daring Dufas]

Yep, the four legged type that barks. ^_^

TDD

[a@b.c]

That's great for new houses. But my house was built back in 1998.

me

[The Daring Dufas]

I believe arc fault circuit breakers could prevent fires in homes with
aluminum Romex. I've heard sizzling inside many junction boxes in many
homes wired with aluminum Romex. O_o

TDD

[a@b.c]

On Wed, 26 Jun 2013 07:08:04 -0700 (PDT), recycl...@gmail.com
wrote:

>On Wednesday, June 26, 2013 3:37:26 AM UTC-7, a...@b.c wrote:
>> My neighbor just suffered a serious fire. His house had an enclosed
>>
>> porch at the rear, with an open, roofed desk connected to the porch
>>
>> rear. He had several GFI breakers out there, including one on the
>>
>> rear porch wall. Around one AM, when he and family were asleep,
>>
>> a fire started at that GFI switch (according to Fire Marshall), and
>>
>> got going pretty good before their dog started barking. That saved
>>
>> their lives for sure. Almost killed their dog and cat, though. The
>>
>> fire badly burned the rear half of the house and sent black soot
>>
>> throughout the rest of the house. The house is pretty well totaled.
>>
>>
>>
>> That's what happened. I have to wonder how a GFI could do that!
>>
>> I heard the Fire Marshall actually say that what happened was the GFI
>>
>> wires arced, but that was not a 'short' to the GFI. Hence it didn't
>>
>> trip. So, the GFI presented no protection did it! The arcing just
>>
>> continued until it started the fire!
>>
>>
>>
>> All this makes me think that my GFIs are not providing me the
>>
>> protection I always thought they did. I'm not sleeping as well these
>>
>> days.
>>
>>
>>
>> Anyone have an opinion about this?
>>
>>
>>
>> Thanks
>>
>>
>>
>> me
>
>1. Did the fire start inside the electrical box of the GFCI or a circuit coming or leaving it?

I don't know

>2. Was the electrical box metal or plastic and was it in a wet location and if so was it an outdoor box?

plastic box not in a wet location (was on the wall between the porch
addition and the roofed open deck behind it)

>3. Was the line connected to the box Romex or was it inside a conduit and if it was inside a conduit was it a EMT or rigid or PVC and was it in a wet location?

I don't know. I'll bet Romex, not in conduit.

Your questions are all germane to the issue and certainly should be
answered.
Thanks for response.
me

[Tony Hwang]

Hi,
My first impression, where is fire/smoke detector?
Poor install(stab wiring?) cheap GFCI product?
Overloaded circuit? Thank the dog, it could be worse.

[bud--]

You can likely add them one way or another. If circuits are multiwire
branch circuits with a common neutral that is a problem.

[RBM]

I don't advise trying to use current technology on older wiring systems.
Aside from Edison circuits, you find anomalies caused by mixed neutrals
and the like. You certainly could test each circuit with an AFCI, and if
it holds, you're good to go

[micky]

Even after looking it up last year, I never did understand what an
Edison circuit is or how it's different from any other circuit.

> you find anomalies caused by mixed neutrals
>and the like. You certainly could test each circuit with an AFCI, and if
>it holds, you're good to go

I know approximately what a mixed neutral is. I don't think my home
described below is likely to have the anomalies you speak of.

My house is from 1979, has quite a bit of empty space in the breaker
box, and there has only been one change, one added circuit, to the
attic to power the attic ceiling light (with receptacle), the roof
fan, and the outdooor floodlight. Along the way it goes by the far
wall of the laundry room where it powers a ceiling light and 5 double
receptacles (no more than 2 sockets are used at any one time, a lamp
and one power tool or another.) The circuit breaker has never
tripped.

Do you think it's likely I'll have problems changing to AFCI?

[cl...@snyder.on.ca]

GFI devices do NOT protect either the wiring or the house. They are
not designed or intended to. They are to protect YOU and others from
shock in the event of a malfunctioning device (power leakage to case).

An "arc fault" detector MAY have prevented the fire - as that is what
they are designed to do. How effective they are, I don't know.

[cl...@snyder.on.ca]

On Wed, 26 Jun 2013 04:17:15 -0700 (PDT), thekma...@gmail.com
wrote:

>Now the question is, did that GFCI preclude the circuit breaker's ability to do its job?

No. It was NOT a short. In most cases it is a loose, intermittenr, or
high resistance connection that causes a fire - not a short.

In order for this to happen there MUST be a load of some sort on the
circuit. A normal breaker will not respond to an "arc fault" of this
type, and nor will a CFCI - an "arc fault detector" breaker is
designed to trip under those conditions. Not sure how effective they
are in real life - or if they are more likely to false trigger.

[cl...@snyder.on.ca]

It had at least one four legged one.

[cl...@snyder.on.ca]

On Wed, 26 Jun 2013 08:57:54 -0400, micky <NONONO...@bigfoot.com>
wrote:

If you have a lot of spare cash.
They are put in bedroom circuits because that is where people are most
likely to be asleep and unaware if a fire were to start there.

[cl...@snyder.on.ca]

So you live in a "pretty new" house. Almost 30 years older than mine
- which is also a "relatively new" house.

[cl...@snyder.on.ca]

Then they were not wired properly. Mine is over 40 years old and not a
single wiring problem - but I AM replacing all switches and outlets
with new COALR devices. Surprisingly, there is no such thing as a
COALR GFCI device available in Canada (according to my electrical
supplier) Need to use GFCI breakers

[micky]

On Wed, 26 Jun 2013 22:09:37 -0400, cl...@snyder.on.ca wrote:

>
>>That's great for new houses. But my house was built back in 1998.
>>
>>me
> So you live in a "pretty new" house. Almost 30 years older than mine
>- which is also a "relatively new" house.

I know how you feel. My house was built in '79 and I think it's
pretty new.

Old is 1930.,

[micky]

Oh. Maybe I should just do my bedroom,






and let any weekend visitors fend for themselves. (I do have smoke
alarms.)

[micky]

On Wed, 26 Jun 2013 21:56:19 -0400, cl...@snyder.on.ca wrote:

> GFI devices do NOT protect either the wiring or the house. They are
>not designed or intended to. They are to protect YOU and others from
>shock in the event of a malfunctioning device (power leakage to case).

You finally made the right point. I didnt' see it until now.

[RBM]

I think you'd be OK, it's houses that predate the 50's where I find all
manner of rube wiring. In your case the only probable issue would be 3
wire circuits, which are two circuits which share a common neutral. AFCI
breakers can't be connected to these circuits. If you open your panel
and find any cables that have a red, black, and white wire, you won't be
able to protect them with an AFCI.

[RBM]

Your house was built in 2028?

[RBM]

AFCI protection is currently required in practically all habitable rooms

[Tony Hwang]

Hi,
Arc and overheating can occur on any loose connection wherever they maybe.

[The Daring Dufas]

The homes I speak of passes inspection at the time using the guidelines
at the time. Aluminum wiring connections will degrade over time due to
the thermal and metallurgical properties of the wire. I've seen
connections fail even when antioxidant compound was used. O_o

TDD

[micky]

Thanks. I"m saving this for next summer, when I'll have time.

[a@b.c]

On Thu, 27 Jun 2013 02:19:19 -0400, micky <NONONO...@bigfoot.com>

Aha! Now I understand what 'common ground' means. My former house
was built in 1980, and had common grounds (3-wire) circuits. I
understood how they worked, but I did not realize the danger involved.
Thanks

me

[RBM]

These circuits, which are called multiwire branch circuits, three wire
circuits, or Edison circuits, are common "neutral" in that two hot legs,
of different potential share one neutral. Your typical residential
electric service, which is 120/240 is an Edison circuit. When installed
properly, they're no more dangerous than a two wire circuit

[RBM]

The aluminum simply relaxes over time and the connections start arcing.
In areas near salt water, oxidation seemed to rapidly deteriorate the
connections

[Tomsic]

<cl...@snyder.on.ca> wrote in message
news:ru6ns8hqog0f3ch2g...@4ax.com...

I can add some comments about your last point from experience over the last
12 years. I've had circuit-breaker AFCIs on several house circuits during
that time and have had maybe 4-6 nuisance trips overall. A couple happened
when we switched ceiling fan speeds using the fan's wall-box control. The
others happened unexpectedly for no obvious reason.

Frankly, I expected more nuisance trips based upon what I had been hearing
and reading when the installation was new since, at that time, I was working
with one of the NEC code panels and there was a lot of discussion about it.
As I understand it, AFCIs react to an electrical arc by sensing the radio
frequencies that the arc generates. But opening/closing a switch can
generate such an arc (usually very small) and the same thing can happen when
an incandescent lamp filament fails or electric motors with brushes or
inertia switches power up.

Tomsic

[tra...@optonline.net]

An Edison circuit allows you to save running one neutral wire.
Let's say I'm putting in new outlets, a long run from the
panel. There are enough outlets that I would need to pull
two romex cables, ie one hot, one neutral, one ground. Each
cable would serve half those outlets.

With an Edison, I can pull one romex with two hots, one neutral,
one ground. The one neutral is shared by the two groups of
outlets. I've traded two cables for one and reduced the
number of conductors by one, all of which save some $$.

[The Daring Dufas]

When I was running 15kv underground coaxial power cables out in the
middle of The Pacific, the guys working at the island's power plants
discovered that a product, LPS 3 Premier Rust Inhibitor sprayed on the
connections of all their high, medium and low voltage connections kept
them corrosion free in the salt water environment. ^_^

http://www.grainger.com/Grainger/LPS-Rust-Inhibitor-6Y745?Pid=search

http://tinyurl.com/ooefs7w

TDD

[Stormin Mormon]

Thanks for the head up. I can get LPS3 at a hardware some what near me. I replaced a circuit panel box for a friend, a couple years ago. We took out a FPE Stabloc, and put in something modern. Probably saved his life. And his wife and two kids. I could have sprayed all the neutrals and aluminum connctions with that stuff. Well, next time....

Lps1 and Lps2 are lubricants. One dries wet, the other dries dry.
.
Christopher A. Young
Learn more about Jesus
www.lds.org
.
.
"The Daring Dufas" <the-dari...@stinky-finger.net> wrote in message news:kqhmf4$u19$1...@dont-email.me...

[The Daring Dufas]

On 6/27/2013 11:32 AM, Stormin Mormon wrote:
> Thanks for the head up. I can get LPS3 at a hardware some what near me. I replaced a circuit panel box for a friend, a couple years ago. We took out a FPE Stabloc, and put in something modern. Probably saved his life. And his wife and two kids. I could have sprayed all the neutrals and aluminum connctions with that stuff. Well, next time....
>
> Lps1 and Lps2 are lubricants. One dries wet, the other dries dry.
> .

The LPS 3 dries to a waxy film that can be easily removed. I've used it
in motor connection boxes on cooling towers to prevent corrosion. ^_^

TDD

[Stormin Mormon]

I wonder if that would slow down the rust that
eats our vehicles. From road salt.

Would it be suitable to spray on aluminum high
amperage feeder wires, in circuit panel boxes?

I did try Noalox on small .250 push on terminals,
but it ate them away. Sigh. Now I use dielectric
grease for push on terminals.

.
Christopher A. Young
Learn more about Jesus
www.lds.org
.
.

"The Daring Dufas" <the-dari...@stinky-finger.net> wrote in message news:kqi7cf$6j8$1...@dont-email.me...

[Mitt Romley]

On 6/27/2013 12:32 PM, Stormin Mormon wrote:
> Lps1 and Lps2 are lubricants. One dries wet, the other dries dry.

How does something dry wet? If it remained wet, it didn't dry, no? ;-)

[gregz]

LPS3 lasts a year outdoors so they claim. I spray boiled linseed oil on
some auto parts on vehicles. I don't how that would stack up on electrical
connections. Might catch fire.

Greg

[cl...@snyder.on.ca]

On Thu, 27 Jun 2013 00:43:06 -0500, The Daring Dufas

Just saying - over 40 years with "series 2" aluminum wiring and
standard devices (not CoAlr or the previous version of "aluminum
compatible" )and not a single sign of corrosion, degradation, or any
other problems when replacing all the devices with CoAlr to satisfy
insurance inspection. Never a single problem other than 2 outlets that
lost contact tension and were replaced about 7? years ago.

[cl...@snyder.on.ca]

Or the brushes "bounce" on ANY brush motor. I've heard of problems
running vacuum cleaners, older sewing machines, handheld mixers, and
food processors, among other devices. Anything that can produce
multiple sparks. Even unplugging a lamp while it is turned on - if
you don't pull the plug quickly - can trip an AFCI

[cl...@snyder.on.ca]

Just remember - if you use LPS and there IS an arc, you have a fire.
That stuff is pretty flammable. It is a light petroleum base. A bit
of a "catch 22".

[Stormin Mormon]

Oh, that puts my brain in spain, in pain. Far too philosiphical for me.

.
Christopher A. Young
Learn more about Jesus
www.lds.org
.
.

"Mitt Romley" <mi...@romley.gop> wrote in message news:51ccb016$0$63229$c3e8da3$3a1a...@news.astraweb.com...

[gregz]

<a@b.c> wrote:
> My neighbor just suffered a serious fire. His house had an enclosed
> porch at the rear, with an open, roofed desk connected to the porch
> rear. He had several GFI breakers out there, including one on the
> rear porch wall. Around one AM, when he and family were asleep,
> a fire started at that GFI switch (according to Fire Marshall), and
> got going pretty good before their dog started barking. That saved
> their lives for sure. Almost killed their dog and cat, though. The
> fire badly burned the rear half of the house and sent black soot
> throughout the rest of the house. The house is pretty well totaled.
>
> That's what happened. I have to wonder how a GFI could do that!
> I heard the Fire Marshall actually say that what happened was the GFI
> wires arced, but that was not a 'short' to the GFI. Hence it didn't
> trip. So, the GFI presented no protection did it! The arcing just
> continued until it started the fire!
>
> All this makes me think that my GFIs are not providing me the
> protection I always thought they did. I'm not sleeping as well these
> days.
>
> Anyone have an opinion about this?
>
> Thanks
>
> me

A gfi has a circuit. Circuits can catch fire. I saw one circuit with a MOV,
which can catch fire. They should have fusing on the circuits, which I
doubt many have. The real question is the quality of the box, but if the
front flares up, what are you going to do.

Greg

[micky]

On Thu, 27 Jun 2013 06:27:09 -0700 (PDT), "tra...@optonline.net"
<tra...@optonline.net> wrote:

>
>>
>> Even after looking it up last year, I never did understand what an
>>
>> Edison circuit is or how it's different from any other circuit.
>>
>>
>
>An Edison circuit allows you to save running one neutral wire.
>Let's say I'm putting in new outlets, a long run from the
>panel. There are enough outlets that I would need to pull
>two romex cables, ie one hot, one neutral, one ground. Each
>cable would serve half those outlets.
>
>With an Edison, I can pull one romex with two hots, one neutral,
>one ground. The one neutral is shared by the two groups of
>outlets. I've traded two cables for one and reduced the
>number of conductors by one, all of which save some $$.

Thanks. This all seems so simple now, I wonder why I didn't
understand it the last time. ~~~~~!
>

[Tomsic]

<cl...@snyder.on.ca> wrote in message
news:r2qps81tasp7g7pgj...@4ax.com...

All are certainly possibilities. So, there's some way in the AFCI sensing
circuit to adjust the level of RF that trips the AFCI. I wonder if there
are any AFCI products out there where that adjustment can be changed within
a range to maintain a level of protection while minimizing nuisance tripping
on noisy systems.

Tomsic

[John Grabowski]

*About a year ago a customer called me about a circuit breaker that kept
tripping when they used their treadmill exercise machine. The breaker was
an arc fault type and the problem only occurred when the machine was shut
off . Long story short, I found that by using an extension cord to power
the treadmill from the same receptacle and circuit, the problem stopped.

[bud--]

On 6/26/2013 3:41 PM, RBM wrote:
> On 6/26/2013 6:01 PM, bud-- wrote:
>> On 6/26/2013 8:47 AM, a@b.c wrote:
>>> On Wed, 26 Jun 2013 10:12:30 -0400, "John Grabowski"

>>> <jgra...@optonline.net> wrote:
>>>
>>>>
>>>>>>>> My neighbor just suffered a serious fire. His house had an enclosed
>>>>>>>> porch at the rear, with an open, roofed desk connected to the porch
>>>>>>>> rear. He had several GFI breakers out there, including one on the
>>>>>>>> rear porch wall. Around one AM, when he and family were asleep,
>>>>>>>> a fire started at that GFI switch (according to Fire Marshall), and
>>>>>>>> got going pretty good before their dog started barking. That saved
>>>>>>>> their lives for sure. Almost killed their dog and cat, though. The
>>>>>>>> fire badly burned the rear half of the house and sent black soot
>>>>>>>> throughout the rest of the house. The house is pretty well totaled.
>>>>>>>>
>>>>>>>> That's what happened. I have to wonder how a GFI could do that!
>>>>>>>> I heard the Fire Marshall actually say that what happened was
>>>>>>>> the GFI
>>>>>>>> wires arced, but that was not a 'short' to the GFI. Hence it didn't
>>>>>>>> trip. So, the GFI presented no protection did it! The arcing just
>>>>>>>> continued until it started the fire!
>>>>>>>>
>>>>>>>> All this makes me think that my GFIs are not providing me the
>>>>>>>> protection I always thought they did. I'm not sleeping as well
>>>>>>>> these
>>>>>>>> days.
>>>>>>>>
>>>>>>>> Anyone have an opinion about this?
>>>>>>>>
>>>>>>>> Thanks
>>>>>>>>
>>>>>>>> me
>>>>>>>>

>>>>>>> GFCI devices don't provide short circuit protection. They provide
>>>>>>> ground
>>>>>>> fault protection. The device that would have, should have
>>>>>>> prevented this
>>>>>>> is the circuit breaker, or better still, an arc fault circuit
>>>>>>> breaker
>>>>>>
>>>>>>

>>>>>> Right, the usual GFCI does not against electrical arcs. The National
>>>>>> Electrical Code now requires arc fault circuit interrupters (AFCI) in
>>>>>> certain rooms of homes to reduce such fires. Wikipedia has a good
>>>>>> summary
>>>>>>


>>>>>

>>>>> So it seems like the ground fault is especially useful near water
>>>>> faucets and wet places.
>>>>>
>>>>> But the arc fault seems especiallly useful everywhere, not just
>>>>> bedrooms. Does that mean every circuit breaker should be arc fault?
>>>>
>>>>
>>>> *Article 210.12 in the 2011 National Electrical Code requires them for
>>>> almost every circuit in a home.

In general, if a house circuit does not need GFCI protection it needs
AFCI protection.

AFCIs include ground fault protection at about 30mA (GFCIs are 5mA).
I suspect that without the ground fault protection the neutral wouldn't
have to be wired through an AFCI.

>>>
>>> That's great for new houses. But my house was built back in 1998.
>>>
>>> me
>>
>> You can likely add them one way or another. If circuits are multiwire
>> branch circuits with a common neutral that is a problem.
>>
> I don't advise trying to use current technology on older wiring systems.

> Aside from Edison circuits, you find anomalies caused by mixed neutrals

> and the like. You certainly could test each circuit with an AFCI, and if
> it holds, you're good to go

Mixed neutrals and "anomalies" can cause other problems.

If someone wants to add AFCI protection, another option is AFCI
receptacles - Leviton is supposed to have one (maybe other
manufacturers?). Like a GFCI receptacle, an AFCI receptacle will protect
what is plugged into it, and what is wired downstream through the
receptacle. If all the load is at the receptacle or downstream it should
protect the upstream wiring from series arcs (loose connections) but not
parallel arcs (H-N & H-G arcs).

Under the 2011 NEC, for new circuits protection can be an AFCI
receptacle installed as the first device with the rest of the circuit
wired through it, but the code is rather restrictive about the wiring
method from the panel to the AFCI receptacle. The AFCI receptacle can be
mounted next to the panel (which can protect fused circuits).

For extensions to existing circuits, where the extension is in areas
that require AFCI protection, that protection must be provided. It can
be done with an AFCI breaker, or an AFCI receptacle can be installed
where the extension takes off (or upstream from that point).

AFCIs look at the arc "signature", which is more than just RF content.
Last I heard detection is for arcs 5A or higher.

[Tomsic]

"John Grabowski" <jgra...@optonline.net> wrote in message
news:51cd73d4$0$21169$607e...@cv.net...

Great idea. Add a little "R", "L" and "C" with an extension cord or line
filter on a noisy load and attenuate the RF before it gets back to the AFCI.

Tomsic

[cl...@snyder.on.ca]

A 10 foot extention cord coiled up beside the treadmill makes a
pretty good choke.

[Robert Green]

"Tomsic" <N...@no.net> wrote in message news:kqh8bp$d8g$1...@dont-email.me...

<stuff snipped>

> Frankly, I expected more nuisance trips based upon what I had been hearing
> and reading when the installation was new since, at that time, I was
working
> with one of the NEC code panels and there was a lot of discussion about
it.

I agree that the "scuttlebutt" was not favorable regarding nuisance trips.
I was thinking about installing them, too, a while back but after all the
bad luck I had with the first CFL's to hit the market, I decided to wait out
being a pioneer for arc fault technology.

> As I understand it, AFCIs react to an electrical arc by sensing the radio
> frequencies that the arc generates.

That's fascinating. I just learned that the local water authority monitors
the rebar in their 60"+ concrete water mains acoustically. When one of the
reinforcing bars snaps, it sends out a unique sound that is monitored by a
series of microphones throughout the system and they then replace the pipe
section.

The only problem is that the most recent break occurred where there was no
rebar in one of the large joints. Who would have thunk of monitoring the RF
emissions of an arc or the sound of snapping rebar? As for the AFCI, it
makes sense because the wire leading to the arc must act as a fairly
efficient antenna. I always wondered how an AFCI could differentiate
between normal current draw and the creation of a dangerous arc. Does that
mean you can't use an arc welder on an AFCI protected circuit?

>But opening/closing a switch can
> generate such an arc (usually very small) and the same thing can happen
when
> an incandescent lamp filament fails or electric motors with brushes or
> inertia switches power up.

I can live with a breaker popping when a light bulb pops. I've had normal
breakers do that. I assume that like GFCIs (Clare used the term CFCI - is
there a difference?) as they get more feedback from users, they tweak the
design to handle those false triggers better. My first GFCI used to trip
like crazy for no reason. The most recently bought ones hardly ever trip.
I got so suspicious I even bought a GFCI plug-in tester to make sure they
were working. (They were.)

Somewhere out there there's information about nuisance trips and whether
they were over-hyped to begin with or whether the earlier units just
couldn't detect them as well as the newer units do. Our resident sparkies
should know.

As for AFCI's, my understanding (from way back when) is that they were
recommended for bedrooms and bathrooms where a high current device like a
space heater or a hair dryer could create an arc big enough to start a fire
very quickly. I can attest that a space heater plugged in only partially
can create enough heat to melt plastic. DAMHIKT. (-:

I once took apart a six-outlet extender that was getting warm to discover
the copper cross bars were press-fit and had become loose and were starting
to blacken at the place they were joined. I also noticed that these old
press-fit six way outlet extenders had two copper bladed plugs and were
electrically cross-connected. The one I bought to replace the burned-up one
had only one live plug. The other was plastic and just acted as a
stabilizer. I suppose that's to prevent someone from plugging the extender
into an extension cord and not an outlet. That would make the second plug
electrically live and exposed.

There's really no need I can see to cross-connect the two plugs to the six
outlets. It could be set up so that each plug feeds only three of the six
outlets and then you could plug it into an extension cord without creating
an electrocution hazard. Maybe it was an economy thing. After all, not
putting a second copper plugs has to be cheaper if you're making 10,000 of
these things. The best design would be to use two isolated plugs because
that way something like a remotely switched lamp outlet would still work as
it should.

--
Bobby G.

[bud--]

On 7/1/2013 7:59 AM, Robert Green wrote:
> "Tomsic"<N...@no.net> wrote in message news:kqh8bp$d8g$1...@dont-email.me...
>

>> As I understand it, AFCIs react to an electrical arc by sensing the radio
>> frequencies that the arc generates.
>

> <...>

>
> Who would have thunk of monitoring the RF

> emissions of an arc ...? As for the AFCI, it

> makes sense because the wire leading to the arc must act as a fairly
> efficient antenna. I always wondered how an AFCI could differentiate
> between normal current draw and the creation of a dangerous arc. Does that
> mean you can't use an arc welder on an AFCI protected circuit?

AFCI look for current components that are higher than power line
frequencies. Wires are not antennas. And it is not just the higher
frequencies. AFCIs look for arc "signatures" to separate normal arcs
from "bad" arcs. My guess is they use digital signal processing but I
don't know.

The inductance of a welder transformer might hide a welding arc.

>
> <...>

>
> As for AFCI's, my understanding (from way back when) is that they were
> recommended for bedrooms and bathrooms where a high current device like a
> space heater or a hair dryer could create an arc big enough to start a fire
> very quickly. I can attest that a space heater plugged in only partially
> can create enough heat to melt plastic. DAMHIKT. (-:

The NEC originally required AFCIs only for bedrooms. Those AFCIs could
only detect "parallel" arcs - H-N & H-G. Arcs might have to be 60A to be
detected (series arcs would be 15 or 20A max). The idea, I believe, was
largely to detect arcs between wires in extension cords which were
walked on or abused in other ways.

AFCIs now detect arcs at a 5A level. That can detect a series arc (loose
connection).

And AFCIs include ground fault detection at about 30mA. If there is a
ground present in a cord an arc is likely to include leakage to ground
soon. Arcing at a receptacle can also wind up with leakage to ground.

[Ashton Crusher]

On Wed, 26 Jun 2013 06:37:26 -0400, a@b.c wrote:

>My neighbor just suffered a serious fire. His house had an enclosed
>porch at the rear, with an open, roofed desk connected to the porch
>rear. He had several GFI breakers out there, including one on the
>rear porch wall. Around one AM, when he and family were asleep,
>a fire started at that GFI switch (according to Fire Marshall), and
>got going pretty good before their dog started barking. That saved
>their lives for sure. Almost killed their dog and cat, though. The
>fire badly burned the rear half of the house and sent black soot
>throughout the rest of the house. The house is pretty well totaled.
>
>That's what happened. I have to wonder how a GFI could do that!
>I heard the Fire Marshall actually say that what happened was the GFI
>wires arced, but that was not a 'short' to the GFI. Hence it didn't
>trip. So, the GFI presented no protection did it! The arcing just
>continued until it started the fire!
>
>All this makes me think that my GFIs are not providing me the
>protection I always thought they did. I'm not sleeping as well these
>days.
>

I may never sleep again.

[Robert Green]

"bud--" <remove....@isp.com> wrote in message
news:51d2ef35$0$1758$c3e8da3$14a0...@news.astraweb.com...

> On 7/1/2013 7:59 AM, Robert Green wrote:
> > "Tomsic"<N...@no.net> wrote in message news:kqh8bp$d8g$1...@dont-email.me...
> >
> >> As I understand it, AFCIs react to an electrical arc by sensing the
radio
> >> frequencies that the arc generates.
> >
> > <...>
> >
> > Who would have thunk of monitoring the RF
> > emissions of an arc ...? As for the AFCI, it
> > makes sense because the wire leading to the arc must act as a fairly
> > efficient antenna. I always wondered how an AFCI could differentiate
> > between normal current draw and the creation of a dangerous arc. Does
that
> > mean you can't use an arc welder on an AFCI protected circuit?
>
> AFCI look for current components that are higher than power line
> frequencies. Wires are not antennas.

I'm not sure I understand the last sentence. Do you mean that the AFCI's
don't use the powerline to transmit the "noise" created by an arc to the
detector/signal processor in the AFCI? From what I've been reading at least
some part of the detection process is based on detecting the RF noise from
an arc. I also read that detecting an arc is difficult because it may not
be drawing detectibly larger amounts of current than a normal device might.

One of my CCTV cameras is badly shielded an acts as an arc detector.
Whenever I run a motor with brushes near it, the image starts to show random
blips across the screen. It's really noticeable when an old power drill is
operated anywhere near the camera. I've been assuming that noise is one
part of what an AFCI "looks" for in trying to determine if arcing is
present.

I'm asking because I've got three different items that appear to use the
home powerline as "antennas" although perhaps that's not the right term.
Each devices uses the powerlines in a slightly different way. X10 home
automation controllers inject a 120kHz RF signal onto the powerlines to
communicate commands. My Netgear Ethernet adapter sends networking signals
over the home powerlines with plug-in adapters (sometimes - it's not very
reliable):

http://www.netgear.com/home/products/powerline-and-coax/

I've seen numerous discussion refer to the HomePlug technology as
"transmitting" ethernet signals over the powerline. Is the powerline acting
as an antenna in those cases or is their a better terminology for what's
happening?

> And it is not just the higher
> frequencies. AFCIs look for arc "signatures" to separate normal arcs
> from "bad" arcs. My guess is they use digital signal processing but I
> don't know.

I would also guess that the AFCI's are looking for several parameters to
determine if there's an arc fault. I would suspect that sort of detection
has improved greatly since the first units hit the market.

This site (from 1999!) claims:

http://ecmweb.com/content/using-arc-fault-circuit-interrupters-reduce-residential-fires

<<Enormous progress has been made recently by manufacturers of AFCIs and
engineers/scientists developing the standard in understanding the variety of
conditions an AFCI must respond to in order to be effective. A reflection of
that understanding is in the variety of tests and conditions under the three
categories of the draft standard. These address the majority of arcing
conditions known to lead to fire.>>

> The inductance of a welder transformer might hide a welding arc.

Haven't been able to find information about how AFCIs and arc welders
interact but it seems most run off 240VAC and would have their own circuit,
probably without an AFCI.

> > As for AFCI's, my understanding (from way back when) is that they were
> > recommended for bedrooms and bathrooms where a high current device like
a
> > space heater or a hair dryer could create an arc big enough to start a
fire
> > very quickly. I can attest that a space heater plugged in only
partially
> > can create enough heat to melt plastic. DAMHIKT. (-:
>
> The NEC originally required AFCIs only for bedrooms. Those AFCIs could
> only detect "parallel" arcs - H-N & H-G. Arcs might have to be 60A to be
> detected (series arcs would be 15 or 20A max). The idea, I believe, was
> largely to detect arcs between wires in extension cords which were
> walked on or abused in other ways

This site talks about the original bedroom requirements and says it's
because that's where many home electrical fires start:

http://www.peterspirito.com/afci_faq.htm#12

<<Why do the 1999, 2002, and 2005 versions of the NEC® require AFCI
protection for only bedroom circuits?

NFPA fire statistics show that a high percentage of electrical fires occur
in bedrooms. There are many appliance cords in bedrooms, for example,
radios, clocks, blankets, air conditioners, heaters, TVs, vacuums, as well
as, lamp cords. All of these cords can be trapped/abused leading to arcing
faults. Further, there are long runs of installed wiring (M-B, "Romex")
between the loadcenter and the bedroom outlets. The wiring can be abused
during installation (e.g. stapling) and after installation (driving nails
into the wall etc.) Therefore, the most logical room to start with would be
the bedroom. >>

The same site also implies that arc welders do not generate nuisance trips
with the newer AFCIs.

> AFCIs now detect arcs at a 5A level. That can detect a series arc (loose
> connection).
>
> And AFCIs include ground fault detection at about 30mA. If there is a
> ground present in a cord an arc is likely to include leakage to ground
> soon. Arcing at a receptacle can also wind up with leakage to ground.

The same site has a good roundup of arc fault types and possible causes:

What is an arcing fault?

According to UL 1699, Standard for Arc Fault Circuit Interrupters, an arcing
fault is an unintentional arcing condition in a circuit. Arcing is defined
as a luminous discharge of electricity across an insulating medium, usually
accompanied by the partial volatilization of electrodes.

There are 3 basic types of arcing faults: line-to-neutral, line-to-ground,
and series arcing.

What causes an arc fault?

Arc faults may occur anywhere in the electrical system and may be a result
of the following:

a.. worn electrical insulation or damaged wire
b.. misapplied or damaged plug in appliance cords and equipment
c.. loose electrical connections
d.. drill bits, nails, or screws driven into the wire
e.. wire staples driven too deep
f.. furniture pressing against electrical cords
g.. broken wires
h.. frayed wires
More reading is in order before I bite the bullet and begin replacing the
rather new <sigh> breakers I installed in the panel just recently. Does
anyone reading this know if AFCI's come in "dual skinny" formats? One of
the site above talks about how AFCI's run warmer than normal breakers
because of the built-in power supply for the electronics. I wonder if they
can squeeze all the required electronics into the dual space-saving
breakers?

Thanks for your input, Bud!

--
Bobby G.

[Robert Green]

<gfre...@aol.com> wrote in message

<stuff snipped>

> The science of AFCIs is proprietary and they are not all the same but
> they look at current, detecting short duration spikes

I'm confused now. Do the AFCI's use RF at all to detect arcing conditions?
I've been trying to find some descriptions or patents that detail how they
work without much success. One interesting site I found:

http://electronicdesign.com/electromechanical/arc-fault-circuit-interrupters-spark-controversy

said that one user, who thought his AFCI was "nuisance tripping" discovered
that it was actually tripping because of a dangerous condition in his
bathroom.

<<"I read all the available information on the Web running into all manner
of grousing, but I also saw an article explaining what the breaker is and
what it does. Encouraged, I started looking for the culprit. On and off it
took me two weeks to separate the circuits to discover that an improperly
installed GFCI socket in the bathroom (on the bedroom socket circuit)
compressed the hot wire against the grounded socket box," he said.
"Old Romex insulation fractured, crumbled, and allowed arcing to the box. I
do not know how long this condition lasted, but now it is fixed," he added.
"In six months, neither of the two breakers disconnected. I am a convert and
I would encourage retrofitting AFCI breakers, especially in older
installations.">>

Maybe it IS time to switch to AFCIs!

--

Bobby G.

[bud--]

On 7/3/2013 3:55 AM, Robert Green wrote:
> "bud--"<remove....@isp.com> wrote in message
> news:51d2ef35$0$1758$c3e8da3$14a0...@news.astraweb.com...
>> On 7/1/2013 7:59 AM, Robert Green wrote:
>>>
>>> Who would have thunk of monitoring the RF
>>> emissions of an arc ...? As for the AFCI, it
>>> makes sense because the wire leading to the arc must act as a fairly
>>> efficient antenna. I always wondered how an AFCI could differentiate
>>> between normal current draw and the creation of a dangerous arc. Does
> that
>>> mean you can't use an arc welder on an AFCI protected circuit?
>>
>> AFCI look for current components that are higher than power line
>> frequencies. Wires are not antennas.
>
> I'm not sure I understand the last sentence. Do you mean that the AFCI's
> don't use the powerline to transmit the "noise" created by an arc to the
> detector/signal processor in the AFCI?

RF from the arc is not picked up by circuit conductors acting as antennas.

AFCIs look at the current on the conductor. The arc "signal" is created
by current variations through the arc.

> From what I've been reading at least
> some part of the detection process is based on detecting the RF noise from
> an arc.

That is the current variations created by the arc.

> I also read that detecting an arc is difficult because it may not
> be drawing detectibly larger amounts of current than a normal device might.

A "series" arc (loose connection) is limited by the normal load that is
on the circuit. The AFCIs that are used now may detect a 5A or larger arc.

Parallel arcs (H-N and H-G) can be a lot larger. The current can be up
to the available short circuit current at the point of the arc. If I
remember right, an investigation found that is very likely over 60A out
to 6 ft of line cord in a house.

>
> One of my CCTV cameras is badly shielded an acts as an arc detector.
> Whenever I run a motor with brushes near it, the image starts to show random
> blips across the screen. It's really noticeable when an old power drill is
> operated anywhere near the camera. I've been assuming that noise is one
> part of what an AFCI "looks" for in trying to determine if arcing is
> present.

The signal from the camera isn't very large so a small noise can be
quite visible.

AFCIs need a 5A or larger "noise" on power wiring that runs at much
higher voltage and current than the camera.

[bud--]

On 7/3/2013 4:07 AM, Robert Green wrote:
> <gfre...@aol.com> wrote in message
>
> <stuff snipped>
>
>> The science of AFCIs is proprietary and they are not all the same but
>> they look at current, detecting short duration spikes
>
> I'm confused now. Do the AFCI's use RF at all to detect arcing conditions?

Looking at the current in the wire, a "spike" is made up of frequencies
that are much higher than 60 Hz. My guess is AFCIs look at the low end
of RF and what is in the audio frequencies. I would also guess AFCIs
pick up the current signal with a current transformer on the hot wire.
(GFCIs use a current transformer around both the hot and neutral.)

[Nate Nagel]

In my limited experience with them, I haven't had any issues. Every
time it's tripped it's been because of a legitimate problem.

Also, the amount of improper wiring that I found in my last house,
combined with simple age and the tendency for old 60C wiring to become
brittle in ceiling light boxes, makes me think that in general they're a
good idea. I lived in my last place for almost a year before going up
in the attic and doing a serious investigation of the wiring, what if
something had happened before I started fixing everything? And since
everything was working, a homeowner less inclined to do it themselves
could have lived there a decade or more unaware of any potential issues
(as I believe to be the case of the previous owners.)

No, they're not a replacement for proper wiring products and methods,
but in a structure where the wiring is apparently in good shape but
known to be old and not up to today's code, it makes sense. For newer
houses where everything's right, it might be overkill, but won't hurt
anything either.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

[Robert Green]

<gfre...@aol.com> wrote in message

<stuff snipped>

> >"Old Romex insulation fractured, crumbled, and allowed arcing to the box.
I
> >do not know how long this condition lasted, but now it is fixed," he
added.
> >"In six months, neither of the two breakers disconnected. I am a convert
and
> >I would encourage retrofitting AFCI breakers, especially in older
> >installations.">>
> >
> >Maybe it IS time to switch to AFCIs!
>

> Most nuisance trips can be traced to a ground fault, not an arc,
> usually in the neutral.

I wonder if it's really fair to call them nuisance trips if there's a real,
underlying electrical fault causing the breaker to open? (-: The more case
studies I read, the more I am convinced that installing AFCI's is a good
thing if only because there almost always *is* a problem of some sort that
they've revealed if they do seem to start tripping for no reason. While
that may not have always been the case - I believe that the first AFCI's did
trip too easily from what I am reading - it seems that now when people
install them and they trip with regularity there's a good reason.

Now the question is - who makes the best AFCIs and do they make them in a
format I can use (dual skinnies)? I can replace the bedroom breakers, which
are mostly single, with full-sized AFCI breakers, but I'd like to protect
other circuits that can carry northward of 10A regularly to be protected as
well.

More Googling required. (It's hard to remember a time when if you wanted to
look something up, you had to go to the library!)

--
Bobby G.

[Robert Green]

"Nate Nagel" <njn...@roosters.net> wrote in message

<stuff snipped>

> In my limited experience with them, I haven't had any issues. Every
> time it's tripped it's been because of a legitimate problem.

It seems that's the case for many people who have installed them.

> Also, the amount of improper wiring that I found in my last house,

You wouldn't believe the things I discovered when I ripped out the poorly
finished basement's walls and ceiling. The additional wiring was done with
equal disrespect. Neutrals pulled from separate circuits, wires nicked by
bad stripping, grounded outlets installed without any grounds, wire nuts
improperly installed, speaker wire instead of Romex, etc.

> combined with simple age and the tendency for old 60C wiring to become
> brittle in ceiling light boxes, makes me think that in general they're a
> good idea. I lived in my last place for almost a year before going up
> in the attic and doing a serious investigation of the wiring, what if
> something had happened before I started fixing everything? And since
> everything was working, a homeowner less inclined to do it themselves
> could have lived there a decade or more unaware of any potential issues
> (as I believe to be the case of the previous owners.)

I have an old house, too, built when WWII was just starting and all sorts of
compromises had to be made because of war shortages (no building paper
between the floors, for example). I can see great benefit in installing
AFCI's to help detect any concealed faults in the wiring system.

I've added a number of new circuits for high-current devices over the years
because I didn't feel comfortable taxing the old, cloth covered wiring with
loads it wasn't designed for, but those circuits are still active. If I
switched them to AFCI's and they started tripping, I would probably just
disconnect them and put in a new circuit with Romex because tracing a fault
through the old wiring would be very hard. The old wiring runs up to the
attic and then down again and everything's behind plaster and lathe walls
and ceilings.

In any event, I agree with you that with old wiring, installing AFCI's could
be a lifesaver.

How much work was involved when you checked/rewired the attic, Nate? I
decided that is was far easier, although slightly more expensive, to just
put in new, grounded 20A circuits from the basement up wherever I could to
replace the 15A cloth-covered wires going up in the attic. I found that the
cloth-covered wires were still mostly OK, except around ceiling junction
boxes and switches that had been replaced. Considerably fraying occurred
wherever the wire had been disturbed for any reason.

> No, they're not a replacement for proper wiring products and methods,
> but in a structure where the wiring is apparently in good shape but
> known to be old and not up to today's code, it makes sense. For newer
> houses where everything's right, it might be overkill, but won't hurt
> anything either.

Agreed.

--
Bobby G.

[gregz]

I installed arc fault breakers on two legs, which included both bedrooms.
This was old wiring. One leg would trip on occasion. I called that leg the
big mess, because if you saw it, that's what yo would call it. Most if that
has been replaced, so far so good.

An arc fault breaker is not also a ground fault is it. Are there some ?

Greg

[Robert Green]

<gfre...@aol.com> wrote in message
> On Thu, 4 Jul 2013 11:02:49 -0400, "Robert Green"
<stuff snipped>

> A ground fault on the neutral will not open the overcurrent device but
> it will trip anything with ground fault protection. A common suspect
> is that big kludge of white wires under a wirenut in a ceiling box.
> That is a common cause of the "fan"problem. The fan vibrates the box
> and a bare ground bumps into an exposed part of a white wire.
> This is a case where taping up a wirenut may be a good idea.

Yes, many sites I've scanned talk about vibration loosening connections in
junction boxes. When a wire pops out of a wire nut it can really create
havoc.

> The size of the AFCI precludes them being in a skinny format ... so
> far.

It looks like my options are not good for replacing all the current breakers
with AFCI's. They're expensive, too, at least the list prices I've seen
are. In most of the new lines I've run, I know where the first outlet in
the circuit is located and I can replace it with a AFCI outlet instead of a
breaker except that most of those outlet boxes are occupied by GFCI's. )-:
I am not fond of using outlet protection devices because it means you have
to go all over the house when a GFCI/AFCI outlet "pops" - been there, done
that. That reminds me to annotate the breaker box legend with the location
of all the GFCI outlets . . .

Besides, it's not the new circuits I am worried about. It's the old,
cloth-covered wire circuits that I am most concerned about. I'll have to
review the circuit panel and decide which ones regularly carry more than 5A
and will consider replacing those regular breakers with AFCI units. From
what Bud has said, an AFCI requires at least that much current to trip.

--
Bobby G.

[Robert Green]

"bud--" <remove....@isp.com> wrote in message

news:51d4287d$0$7154$c3e8da3$b135...@news.astraweb.com...

60A through a 14GA cord is going to do some damage. I remember when I was a
kid an electrician working on the circuit panel with a screw driver shorted
it out inside the box with a huge spark that spattered molten metal inside
the circuit panel. I still have that screw driver around somewhere. He
just tossed it in the trash because the tip was cratered but I retrieved it
because I thought it made a great souvenir and reminder to be careful.

> > One of my CCTV cameras is badly shielded an acts as an arc detector.
> > Whenever I run a motor with brushes near it, the image starts to show
random
> > blips across the screen. It's really noticeable when an old power drill
is
> > operated anywhere near the camera. I've been assuming that noise is one
> > part of what an AFCI "looks" for in trying to determine if arcing is
> > present.
>
> The signal from the camera isn't very large so a small noise can be
> quite visible.

It's clear now from what you've said and what I've read that it's not a
"radio" process but a monitoring of the instantaneous current draw that
detects the arc. I wonder if the radio telegraphs used in the Marconi era
would work today with all the background RFI that exists today?

> AFCIs need a 5A or larger "noise" on power wiring that runs at much
> higher voltage and current than the camera.

The camera is only of use in detecting things like motors with brushes that
need replacing. It even detects when a gasoline-powered leaf blower is
nearby.

--
Bobby G.

[Robert Green]

"gregz" <ze...@comcast.net> wrote in message
news:1093161559394683402.882372zekor-

<stuff snipped>

> I installed arc fault breakers on two legs, which included both bedrooms.
> This was old wiring. One leg would trip on occasion. I called that leg the
> big mess, because if you saw it, that's what yo would call it. Most if
that
> has been replaced, so far so good.

Yeah, I had a similar circuit in the basement that had been hacked into by
hack amateurs so many times that yanking it was the only thing to do. It
was the circuit that had speaker wire coming out of one junction box and
going into a flourescent shoplite without any strain relief. The wires went
right into a sharp-edged sheet metal hole that had already begun to saw
through the insulation. Yikes!

> An arc fault breaker is not also a ground fault is it. Are there some ?

Good question. I seem to recall reading something about one, but I can't
recall whether it was an actual product or a prediction. I also came across
someone who's promoting a scheme whereby all outlets and all plugs have RFID
chips in them so they can communicate with each other and establish what the
normal current load should be. That would make it easier to detect way
out-of-bounds over-current draws, but the scheme sounds too complicated to
ever be adapted universally. If I find a combo AFCI/GFCI unit, I will let
you know. I suspect if it's available, it would only be in an outlet
form-factor.

--
Bobby G.

[Robert Green]

"bud--" <remove....@isp.com> wrote in message

news:51d42b22$0$1355$c3e8da3

> On 7/3/2013 4:07 AM, Robert Green wrote:

<stuff snipped>

> > I'm confused now. Do the AFCI's use RF at all to detect arcing
conditions?
>
> Looking at the current in the wire, a "spike" is made up of frequencies
> that are much higher than 60 Hz. My guess is AFCIs look at the low end
> of RF and what is in the audio frequencies. I would also guess AFCIs
> pick up the current signal with a current transformer on the hot wire.
> (GFCIs use a current transformer around both the hot and neutral.)

It's interesting that in all my research I've yet to come across a circuit
diagram or anything technically detailed about how AFCIs actually work. I'm
going to bite the bullet and order an AFCI outlet to run some tests with.
They ain't cheap!

http://www.amazon.com/Leviton-AFTR2-GY-SmartlockPro-Interrupter-Receptacle/dp/B009ZZCKG8

runs $33 from Amazon. If anyone knows of a cheaper vendor, please advise.
Also, how would one go about creating a deliberate arc for testing purposes?
I've got some carbon rods lying around somewhere that I used to create a
carbon-arc light with. I suppose that should work . . .

--
Bobby G.

[TimR]

I found this quote on a Inspectapedia, home inspection site:

"As of September 2008 we have found no test tool that reliably and completely tests the function of an AFCI. Only the integral test button tests the circuitry of the device as well as the trip mechanism. UL classes these "test" devices not as "testers", but as "indicators".

A problem is that some devices used to "inspect" an AFCI, in trying to produce a simulated arc fault condition, may fail to cause the AFCI device to trip even though it is perfectly fine.

Literature from the manufacturer of a popular "test tool" tells the user of the tool to go to the electric panel and use the test button on the AFCI device to make sure it trips. In other words the inspector cannot rely on the separate test tool. For this reason you will see such tools referred to as "indicators" rather than "testers": they are not a complete and reliable test instrument for AFCIs"

So, trust the test button, because there is NO external way to verify the device works? Huh? Does that make sense?

[Robert Green]

"bud--" <remove....@isp.com> wrote in message

news:51d4287d$0$7154$c3e8da3
<stuff snipped>

> AFCIs need a 5A or larger "noise" on power wiring that runs at much
> higher voltage and current than the camera.

I've noticed that almost all the AFCI breakers I've been looking at have
pigtails attached. Those are going to make for a very messy looking
installation in my cramped box, IMHO. I see that one of the newer circuit
panels has accommodations for the AFCI pigtails but now we're talking
serious expense and time to replace my old panel with an AFCI compatible
one.

One of the sites I browsed made an interesting comment:

<<The new arc fault breakers cost about $25 - $50 each depending upon
manufacturer, but it is a very small price to pay for peace of mind. An
experienced electrician can install a new arc fault breaker in a matter of
minutes. It actually takes longer to remove and replace the cover to the
circuit breaker panel than it does to switch out the breaker>>

The breakers, to my surprise, all seem to be more expensive on the whole
than a OBC (Outlet Branch Circuit) outlet-format protector. So $50 x 20
breakers is $1,000. The real problem is that now I know that the AFCI's
require pigtails and full breaker slots, it means I would feel compelled to
pull the old box, replace any cloth-wired circuits coming into back to their
source (that's the long pole in the tent) and put in a new box designed for
AFCI's and then probably have to heavy-up the service to the pole. So the
math isn't quite as clean as $50 by 20. I'd think that's a multi $K job for
a licensed electrician and at least $2K for a homeowner DIY'er if everything
listed is done.

What do electricians charge to run a new branch circuit in old plaster/lathe
construction? I've always done it myself so I confess, I have no idea.

The question now is how much is piece of mind worth? Is the money better
spent on a panel full of GFCIs or on smoke, heat, CO detectors or other
safety technology? AFCI's, once perfected, could just as easily ride the
main breaker, couldn't they? The arcing "information/signature" should be
detectable at the service entrance, shouldn't it? Admittedly nuisance trips
that bring the whole home "grid" down aren't going to be pleasant, but I
know that the new home industry would rather not have to add over $1000 in
AFCI costs to new homes if there's a cheaper way to do it.

One site said that there are at least 111 arc-fault based fires in the US
each year. Statistically, that's really not a light. Can't vouch for the
accuracy of the number. Seems like it should be higher. Could be CRS or
the webmaster took a WAG. (-:

Is it time to switch out the old breakers or will there be combo AFCI/GFCI
breakers sometime down the line? I see that some of the AFCI's incorporate
a form of GFCI, but the trigger appears to be 30mA and GFCI's appear to
operate at a more life-saving 5mA level.

I did notice that more than one site (Leviton and Eaton/CH, I think) took
pains to point out that they are continuously improving their arc detection
capabilities. Cynical people might take that as an acknowledgment that they
feel they are "not quite there yet" in terms of 100% reliability.

--
Bobby G.

[Robert Green]

"TimR" <timot...@aol.com> wrote in message
news:03e728ca-4bc3-441d...@googlegroups.com...

>I found this quote on a Inspectapedia, home inspection site:

"As of September 2008 we have found no test tool that reliably and
completely tests the function of an AFCI. Only the integral test button
tests the circuitry of the device as well as the trip mechanism. UL classes
these "test" devices not as "testers", but as "indicators".

Funny you should bring that up because the Eaton/CH site I was reading
mentioned using a circuit analyzer *before* installing an AFCI to help scan
for potential problems that would cause a nuisance trip. So I started
looking at circuit analyzers that could tell me if there was a problem with
the in-wall wiring. The cheapest I found was $90 for this:

NEEWER® TRMS Voltage GFCI RCD Tester Circuit Analyzer MS5908A but it doesn't
appear to test AFCIs although it does test for Residual Current Devices
which turn out to be like a GFCI, but speak with a British accent <g>. From
Mike Holt's forums:

< RCD is the term normally used in the UK, and the most common trip rating
is 30ma though many other ratings exist. A UK type RCD normaly only protects
against leakage to earth/ground, and does not protect against overload or
short circuit, a fuse or MCB must also be employed to protect against short
circuit or overload. A combined earth leakage and overload protective device
is available, these are known as RCBOs. A UK RCD built into an outlet does
NOT protect downstream outlets. The common 30ma trip current does in
practice give good (but not total) protection against shock, especialy as
they normally trip at about 20/25ma, and are faster acting than USA GFCIs.>

http://forums.mikeholt.com/showthread.php?t=122329

The other tester they just got pricier from there: Amprobe INSP-3 Wiring
Inspector Circuit Tester Was almost $300 and folks on Amazon had some
complaints about it.

The Ideal Industries 61-165 SureTest Circuit Analyzer weighed in at over
$330 but deals with both AF and GF CI's but users complained that it was
"short" some necessary adapters.

So it looks, at first glance, like a circuit analyzer that can "test" AFCI's
will set me back the cost of at least 6 AFCI breakers. The question now is
will testing all the circuits reveal the same sorts of problems that
nuisance tripping of AFCIs would also "detect?" Is money better spent on
the AFCI's themselves or on a tool that can reveal potential hazards?

> A problem is that some devices used to "inspect" an AFCI, in trying to
produce a
> simulated arc fault condition, may fail to cause the AFCI device to trip
even though it is
> perfectly fine.

Gives you that "warm, fuzzy" feeling about their overall effectiveness,
doesn't it? That's precisely why I've been thinking of buying a single OBC
outlet AFCI unit and testing it under real world arcing conditions that I
create - the kind of testing that drives SWMBO mad. (-:

> Literature from the manufacturer of a popular "test tool" tells the user
of the tool to go
> to the electric panel and use the test button on the AFCI device to make
sure it trips.
> In other words the inspector cannot rely on the separate test tool. For
this reason you will
> see such tools referred to as "indicators" rather than "testers": they are
not a complete and
> reliable test instrument for AFCIs"

Great. This AFCI investigation is rapidly spreading out into a murky
wamp. )-;

> So, trust the test button, because there is NO external way to verify the
device works?
> Huh? Does that make sense?

Only in Bizzaro land. (-: What bothers me most about the lack of testers
that can actually TEST and not just INDICATE is that I would always be
suspicious that the AFCI's might not react to a real arc. There's something
just not scientific about not being able to create a reliable, repeatable
tester for a device intended to save your life. Sometimes, when
manufacturers have problems like nuisance trips, their first corrective
attempts overshoot the mark.

I guess I had just better order a single AFCI and start testing while I try
to decide whether a $300 circuit tester would be a good investment.

--
Bobby G.

[Robert Green]

"RBM" <r...@noemail.com> wrote in message news:51cbad44$0$25618

<stuff snipped>

> I think you'd be OK, it's houses that predate the 50's where I find all
> manner of rube wiring. In your case the only probable issue would be 3
> wire circuits, which are two circuits which share a common neutral. AFCI
> breakers can't be connected to these circuits. If you open your panel
> and find any cables that have a red, black, and white wire, you won't be
> able to protect them with an AFCI.

Are you sure that's still true?

http://w3.usa.siemens.com/powerdistribution/us/en/product-portfolio/circuit-breakers/residential-circuit-breakers/2-pole-afci/pages/2-pole-afci.aspx

<<The 2-pole device can reduce wiring costs and installation time by
enabling contractors to use multi-wire branch circuits, commonly known as
"shared neutrals". When using single pole CAFCIs, a dedicated neutral is
required for each circuit. The new 2-pole CAFCI allows electricians to share
neutrals between the two circuits fed by the breaker.>>

--
Bobby G.

[Robert Green]

<tra...@optonline.net> wrote in message news:6de381a1-ed1f-4c06-9d38-

<stuff snipped>

> With an Edison, I can pull one romex with two hots, one neutral,
> one ground. The one neutral is shared by the two groups of
> outlets. I've traded two cables for one and reduced the
> number of conductors by one, all of which save some $$.

From my understanding of MWC's (which could easily be wrong) if the shared
neutral fails for any reason, you can potentially end up with much more than
120VAC where you don't want it. If a neutral fails in normally wired pair
of outlets, there's usually no risk of voltage escalation or imbalance.
However a failer neutral in a MWC can play out like this:


http://www.ecmweb.com/images/archive/205ecm18fig1.gif

There are a couple of other considerations that affect the cost analysis,
too. I have always been able to buy 12/2 w/g Romex on sale for much less
than 12/3 w/g. So much less, in fact, that there was no difference in the
price between running two 12/2 cables and using a MWC using 2/3. I assume
that's a function of how much more 12/2 is manufactured than 12/3. It took
a little longer to install and staple, but I really prefer separate
neutrals. I assume that the different in installation time is a much bigger
concern to builders of large tracts of homes.

MWC's require (at least I am pretty sure NEC and CEC say so) a double pole
breaker requiring de-energizing both circuits to do repairs. Not a big
issue, but at times it's been nice to have a nearby live outlet to plug
tools into when I am working on a different circuit in the room. Not sure
if the DP breakers with a single handle for MWC's come in "dual skinny"
format, either, which is another concern for folks wanting to add new
circuits to an older box.

I do have one multiwire circuit in the panel to power my XTB X10
repeater/coupler/amplifier but nothing else is plugged into that outlet,
which has about 6' of wire running to the nearby circuit panel. Even that
outlet is wired with two separate runs of 12/2 w/g Romex.

I am sure there are labor cost savings for developers building a series of
houses, but in my case MWC's didn't make much sense except for the special
case of the X10 device that by design has to straddle both hots to
communicate between the phases.

--
Bobby G.

[Robert Green]

"micky" <NONONO...@bigfoot.com> wrote in message
news:3l9ns8hviahar6eq3...@4ax.com...
> On Wed, 26 Jun 2013 22:09:37 -0400, cl...@snyder.on.ca wrote:
>
> >
> >>That's great for new houses. But my house was built back in 1998.
> >>
> >>me
> > So you live in a "pretty new" house. Almost 30 years older than mine
> >- which is also a "relatively new" house.
>
> I know how you feel. My house was built in '79 and I think it's
> pretty new.
>
> Old is 1930.,

I tend to classify houses by technology. Really old is K&T wiring, pretty
old is cloth covered wiring, newer is grounded circuits and newest is
GFCI/AFCI protected.

--
Bobby G.

[bud--]

On 7/5/2013 5:56 AM, Robert Green wrote:
> "bud--"<remove....@isp.com> wrote in message
> news:51d42b22$0$1355$c3e8da3
>>

>> Looking at the current in the wire, a "spike" is made up of frequencies
>> that are much higher than 60 Hz. My guess is AFCIs look at the low end
>> of RF and what is in the audio frequencies. I would also guess AFCIs
>> pick up the current signal with a current transformer on the hot wire.
>> (GFCIs use a current transformer around both the hot and neutral.)
>
> It's interesting that in all my research I've yet to come across a circuit
> diagram or anything technically detailed about how AFCIs actually work. I'm
> going to bite the bullet and order an AFCI outlet to run some tests with.
> They ain't cheap!

I dug into my archive of downloads. Of particular interest is
http://www.cpsc.gov/volstd/afci/AFCIFireTechnology.pdf
why have AFCIs
available fault current on a branch circuit
AFCI detection - block diagram
"bad" arcs and normal arcs
30mA ground fault detection
It might answer some of your questions.
Details of detection, as gfretwell wrote, are probably proprietary.

Likely of less interest is:
http://web.archive.org/web/20080516051937/http://www.iaei.org/subscriber/magazine/03_a/magazine_03_gregmanche.htm
includes info on 5A trip
Note that "branch/feeder AFCIs" were the original ones that did not
detect series arcs and are no longer available.

Prices likely will decline like GFCI prices did. But AFCIs are more
complicated.

>
> http://www.amazon.com/Leviton-AFTR2-GY-SmartlockPro-Interrupter-Receptacle/dp/B009ZZCKG8
>
> runs $33 from Amazon. If anyone knows of a cheaper vendor, please advise.
> Also, how would one go about creating a deliberate arc for testing purposes?
> I've got some carbon rods lying around somewhere that I used to create a
> carbon-arc light with. I suppose that should work . . .
>

You can also use mechanical pencil leads wired in series with a load
that runs at higher than 5A. Pencil leads give a pretty smooth arc. Is
it a "bad" arc or a "normal" arc?
Check the cpsc.gov link for some info on good and normal arcs.

I would just assume that if the test button works the AFCI is OK.
There is a page at UL that says about what TimR got from inspectapedia.
I do not find it surprising that testers are not available.

[bud--]

On 7/4/2013 8:13 PM, gregz wrote:
>
> An arc fault breaker is not also a ground fault is it. Are there some ?
>

AFCIs include ground fault protection. I believe it is required at 50mA
or less and is provided at 30mA. The cpsc.gov link I posted has
information on ground fault protection and why it is included.

GFCIs will trip with a ground fault of 5mA, so AFCIs don't replace
GFCIs. Another difference is that GFCIs have a couple additional
components that will trip the GFCI whenever there is a downstream N-G
connection, load or no-load. AFCIs will trip with a N-G downstream
connection (as gfretwell wrote) but there has to be a load to produce a
voltage drop on the neutral wire.

I don't think the NEC requires both GFCI and AFCI protection at the same
location. GFCI wire-through receptacles can be used downstream from AFCIs.

[bud--]

On 7/5/2013 5:22 AM, Robert Green wrote:
> <gfre...@aol.com> wrote in message
>
>

>> The size of the AFCI precludes them being in a skinny format ... so
>> far.
>
> It looks like my options are not good for replacing all the current breakers
> with AFCI's. They're expensive, too, at least the list prices I've seen
> are. In most of the new lines I've run, I know where the first outlet in
> the circuit is located and I can replace it with a AFCI outlet instead of a
> breaker except that most of those outlet boxes are occupied by GFCI's. )-:
> I am not fond of using outlet protection devices because it means you have
> to go all over the house when a GFCI/AFCI outlet "pops" - been there, done
> that. That reminds me to annotate the breaker box legend with the location
> of all the GFCI outlets . . .

I have a post that covers receptacle-type AFCIs, including that you can
install them adjacent to the panel and use them to protect the circuit
downstream (about the same as an AFCI circuit breaker). For new
circuits, the NEC is particular about the wiring method from panel to
AFCI receptacle.

>
> Besides, it's not the new circuits I am worried about. It's the old,
> cloth-covered wire circuits that I am most concerned about. I'll have to
> review the circuit panel and decide which ones regularly carry more than 5A
> and will consider replacing those regular breakers with AFCI units. From
> what Bud has said, an AFCI requires at least that much current to trip.
>

AFCIs will be most useful when the new circuits they are installed on
become old circuits.

[cl...@snyder.on.ca]

Split circuit receptacles were required by code in kitchens before
GFCIs were required - and the ONLY way to put GFCI protection on these
split kitchen outlets is to use a 2 pole panel mounted device.

Current code prefers non-split 20 amp GFCI outlets within a 59 inch
radius of the sink, but still allows split 15 circuits

[bud--]

On 7/4/2013 8:13 PM, gregz wrote:
>

> An arc fault breaker is not also a ground fault is it. Are there some ?
>

AFCIs include ground fault protection, but it is at about30mA. GFCIs

will trip with a ground fault of 5mA, so AFCIs don't replace GFCIs.

I don't think the NEC requires both GFCI and AFCI protection at the same

location. I haven't seen AFCI+GFCI devices. GFCI wire-through

[Tekkie®]

The Daring Dufas posted for all of us...

And I know how to SNIP

>
> On 6/27/2013 11:32 AM, Stormin Mormon wrote:
> > Thanks for the head up. I can get LPS3 at a hardware some what near me. I replaced a circuit panel box for a friend, a couple years ago. We took out a FPE Stabloc, and put in something modern. Probably saved his life. And his wife and two kids. I could have sprayed all the neutrals and aluminum connctions with that stuff. Well, next time....
> >
> > Lps1 and Lps2 are lubricants. One dries wet, the other dries dry.
> > .
>
> The LPS 3 dries to a waxy film that can be easily removed. I've used it
> in motor connection boxes on cooling towers to prevent corrosion. ^_^
>
> TDD

Doesn't solder well then? ;)

--
Tekkie

[Guv Bob]

Girl Friend Interruptus will definitely cause a fire.

[Stormin Mormon]

What does GFCI do, then?
.
Christopher A. Young
Learn more about Jesus
www.lds.org
.
.
"Guv Bob" <guvbo...@yahooooooooooooooo.com> wrote in message news:MoCdnelr_dDZKEbM...@earthlink.com...

[Nate Nagel]

In my case, not any more than doing it any other way - I didn't have a
good path to the basement and the house was wired the old school way
with the primary wiring paths going from ceiling box to ceiling box so
ripping everything out and starting over was easy. I reused the homerun
to the panel because it was BX and would have been hard to repull. I
did have to pull one run from a wall recep to a ceiling box behind a
plaster (exterior!) wall which if I'd missed it would have required me
to open the wall... but fortunately I didn't mess that one up.


nate

>
>> No, they're not a replacement for proper wiring products and methods,
>> but in a structure where the wiring is apparently in good shape but
>> known to be old and not up to today's code, it makes sense. For newer
>> houses where everything's right, it might be overkill, but won't hurt
>> anything either.
>
> Agreed.
>
> --
> Bobby G.
>
>

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

[Nate Nagel]

On 06/27/2013 09:38 PM, cl...@snyder.on.ca wrote:
> On Thu, 27 Jun 2013 07:45:46 -0400, "Tomsic" <N...@no.net> wrote:
>
>>
>> <cl...@snyder.on.ca> wrote in message
>> news:ru6ns8hqog0f3ch2g...@4ax.com...
>>> On Wed, 26 Jun 2013 04:17:15 -0700 (PDT), thekma...@gmail.com
>>> wrote:
>>>
>>>> Now the question is, did that GFCI preclude the circuit breaker's ability
>>>> to do its job?
>>> No. It was NOT a short. In most cases it is a loose, intermittenr, or
>>> high resistance connection that causes a fire - not a short.
>>>
>>> In order for this to happen there MUST be a load of some sort on the
>>> circuit. A normal breaker will not respond to an "arc fault" of this
>>> type, and nor will a CFCI - an "arc fault detector" breaker is
>>> designed to trip under those conditions. Not sure how effective they
>>> are in real life - or if they are more likely to false trigger.
>>
>> I can add some comments about your last point from experience over the last
>> 12 years. I've had circuit-breaker AFCIs on several house circuits during
>> that time and have had maybe 4-6 nuisance trips overall. A couple happened
>> when we switched ceiling fan speeds using the fan's wall-box control. The
>> others happened unexpectedly for no obvious reason.
>>


>> Frankly, I expected more nuisance trips based upon what I had been hearing
>> and reading when the installation was new since, at that time, I was working
>> with one of the NEC code panels and there was a lot of discussion about it.
>> As I understand it, AFCIs react to an electrical arc by sensing the radio
>> frequencies that the arc generates. But opening/closing a switch can
>> generate such an arc (usually very small) and the same thing can happen when
>> an incandescent lamp filament fails or electric motors with brushes or
>> inertia switches power up.
>>
>> Tomsic
>>
> Or the brushes "bounce" on ANY brush motor. I've heard of problems
> running vacuum cleaners, older sewing machines, handheld mixers, and
> food processors, among other devices. Anything that can produce
> multiple sparks. Even unplugging alamp while it is turned on - if
> you don't pull the plug quickly - can trip an AFCI
>

To be fair, I would be hard pressed to describe the difference between
an undesirable arc and one caused by a plug being withdrawn slowly under
load, so it is hard to fault the breaker for not being able to determine it.

nate

[abdul saleem]

http://Cash4Visits.com/ref.php?refId=267381

[Nate Nagel]

yes they are but not at the same level as a GFCI. A GFCI intended for
personnel protection will trip at 5 mA of fault current, the ones in an
AFCI breaker are a higher threshold, I think 30 mA? so while they do
pretty much the same thing you cannot rely on the AFCI to provide GFCI
protection where required.

[Nate Nagel]

OK, I see that the question was already answered... sorry...

I actually had a situation where I was required to use AFCIs and GFCIs
together. In my last house while I was in the process of rewiring the
upstairs, I had half of the floor properly grounded and half still using
the original cloth covered ungrounded NM cable. Unfortunately the PO of
the place had installed grounding type receptacles anyway throughout
even though there was only originally one box with a proper ground.
Strictly reading the code at that point I could not install ungrounded
receps (I did order some but never installed them - my eventual goal was
to rewire the rest of the floor including the original wiring that was
still reasonably acceptable, but we sold the place first) alternately I
could provide GFCI protection. So that is what I did, I installed a
GFCI recep at the first box on the circuit and an AFCI breaker in the
panel (since it was a floor with three bedrooms.)

It seemed like a Mickey Mouse setup, but I never had any trouble with it.

One concern I did have though was what if someone were living in a house
that needed some kind of life support equipment? Could not a nuisance
trim be potentially fatal? I'm guessing people more knowledgeable than
I have already run the numbers on this and have determined that AFCIs
are less of a net risk than not having them.

[Nate Nagel]

On 06/26/2013 05:41 PM, RBM wrote:
> On 6/26/2013 6:01 PM, bud-- wrote:
>> On 6/26/2013 8:47 AM, a@b.c wrote:
>>> On Wed, 26 Jun 2013 10:12:30 -0400, "John Grabowski"
>>> <jgra...@optonline.net> wrote:
>>>
>>>>
>>>>>>>> My neighbor just suffered a serious fire. His house had an
>>>>>>>> enclosed
>>>>>>>> porch at the rear, with an open, roofed desk connected to the porch
>>>>>>>> rear. He had several GFI breakers out there, including one on the
>>>>>>>> rear porch wall. Around one AM, when he and family were asleep,
>>>>>>>> a fire started at that GFI switch (according to Fire Marshall), and
>>>>>>>> got going pretty good before their dog started barking. That saved
>>>>>>>> their lives for sure. Almost killed their dog and cat, though. The
>>>>>>>> fire badly burned the rear half of the house and sent black soot
>>>>>>>> throughout the rest of the house. The house is pretty well
>>>>>>>> totaled.
>>>>>>>>
>>>>>>>> That's what happened. I have to wonder how a GFI could do that!
>>>>>>>> I heard the Fire Marshall actually say that what happened was
>>>>>>>> the GFI
>>>>>>>> wires arced, but that was not a 'short' to the GFI. Hence it didn't
>>>>>>>> trip. So, the GFI presented no protection did it! The arcing just
>>>>>>>> continued until it started the fire!
>>>>>>>>
>>>>>>>> All this makes me think that my GFIs are not providing me the
>>>>>>>> protection I always thought they did. I'm not sleeping as well
>>>>>>>> these
>>>>>>>> days.
>>>>>>>>
>>>>>>>> Anyone have an opinion about this?
>>>>>>>>
>>>>>>>> Thanks
>>>>>>>>
>>>>>>>> me
>>>>>>>>
>>>>>>> GFCI devices don't provide short circuit protection. They provide
>>>>>>> ground
>>>>>>> fault protection. The device that would have, should have
>>>>>>> prevented this
>>>>>>> is the circuit breaker, or better still, an arc fault circuit
>>>>>>> breaker
>>>>>>
>>>>>>
>>>>>> Right, the usual GFCI does not against electrical arcs. The National
>>>>>> Electrical Code now requires arc fault circuit interrupters (AFCI) in
>>>>>> certain rooms of homes to reduce such fires. Wikipedia has a good
>>>>>> summary
>>>>>> of what GFCIs can and cannot do at:
>>>>>> http://en.wikipedia.org/wiki/Arc-fault_circuit_interrupter Arcing
>>>>>> that
>>>>>> results from loose connection at outlets and switches or broken
>>>>>> wires are
>>>>>> a
>>>>>> major cause of house fires.
>>>>>>
>>>>>> Tomsic
>>>>>
>>>>> So it seems like the ground fault is especially useful near water
>>>>> faucets and wet places.
>>>>>
>>>>> But the arc fault seems especiallly useful everywhere, not just
>>>>> bedrooms. Does that mean every circuit breaker should be arc fault?
>>>>
>>>>
>>>> *Article 210.12 in the 2011 National Electrical Code requires them for
>>>> almost every circuit in a home.

>>>
>>>
>>> That's great for new houses. But my house was built back in 1998.
>>>
>>> me
>>

>> You can likely add them one way or another. If circuits are multiwire
>> branch circuits with a common neutral that is a problem.
>>
> I don't advise trying to use current technology on older wiring systems.
> Aside from Edison circuits, you find anomalies caused by mixed neutrals
> and the like. You certainly could test each circuit with an AFCI, and if
> it holds, you're good to go

If there's a mixed neutral on a non-Edison circuit, that's a code
violation, potentially a hazard, and should be fixed!

[Nate Nagel]

On 06/26/2013 09:39 PM, micky wrote:

> Even after looking it up last year, I never did understand what an
> Edison circuit is or how it's different from any other circuit.

It's basically a 120/240 two-phase circuit with two hots and a neutral.
The advantage of using it is that it requires two less wires to be
pulled than two separate 120VAC circuits, because only one neutral and
one ground is required rather than two of each. The reason that you can
get away with it is that if you are only using 120VAC loads, but they
are evenly split between the two hot legs, the current in the neutral
will actually be zero! This is because the two 120VAC hots are 180
degrees out of phase (they add to a potential of 240VAC) it's very
similar to the way a three phase system works with 480VAC/277VAC if you
are familiar with that but with only two "phases."

Apparently this was devised by Edison as a means to provide two DC
circuits with only three wires (I guess the two "phases" in that case
would have been one wire at the positive nominal voltage relative to
ground and the other would be at negative nominal voltage relative to
ground) and someone appropriated the terminology to include the
analogous AC configuration... which makes sense as we all know that
Edison was a proponent of DC not AC. (Tesla and Westinghouse were the AC
guys...)

The problem with using an AFCI on an Edison circuit is that you would
need a two pole breaker, which do exist but are unsurprisingly more
expensive than a single pole unit (or even two single pole units!) An
alternative would be two single pole breakers, but the manufacturer
would have to list them as being acceptable to use with a handle tie and
I haven't researched it enough to determine if there are any like that
or not.

https://www.platt.com/platt-electric-supply/Circuit-Breakers-Residential-Arc-Fault-Breakers/Eaton/CH220AF/product.aspx?zpid=473677

>
>> you find anomalies caused by mixed neutrals
>> and the like. You certainly could test each circuit with an AFCI, and if
>> it holds, you're good to go
>

> I know approximately what a mixed neutral is. I don't think my home
> described below is likely to have the anomalies you speak of.
>
> My house is from 1979, has quite a bit of empty space in the breaker
> box, and there has only been one change, one added circuit, to the
> attic to power the attic ceiling light (with receptacle), the roof
> fan, and the outdooor floodlight. Along the way it goes by the far
> wall of the laundry room where it powers a ceiling light and 5 double
> receptacles (no more than 2 sockets are used at any one time, a lamp
> and one power tool or another.) The circuit breaker has never
> tripped.
>
> Do you think it's likely I'll have problems changing to AFCI?
>

I'm assuming what he means by a "mixed neutral" is one where neutrals
from one circuit are cross-connected to another circuit. That would be
a code violation and has been for ages - when neutrals from different
circuits are connected together you can no longer assure that the
currents in a cable sum to zero which has been a requirement for a very
long time.

So... you shouldn't have that situation, and if you do, might as well
find out about it now and fix it (should not require opening any walls
unless you have hidden splices which would be another violation...)

[Nate Nagel]

That's a Canadian thing... it is not required in the US and appears not
to be common practice although it would still make sense to do it that
way in many situations.