Electrical flash behind light switch plate

[affili...@gmail.com]

I am wondering if this is normal. I can see flashes of light sometimes
when I flick on various light switches around the house. It's
intermitent but most noticeable at night when there is little light in
the room. I am nervous this is going to start a fire. Spoke with the
developer they said it's normal. Any thoughts?

[Toller]

<affili...@gmail.com> wrote in message
news:1150935124.7...@c74g2000cwc.googlegroups.com...

This has to be a troll. Even the worst arc wouldn't be visible with a
switchplate in place.

But just in case it isn't; no, a significant arc when using a switch isn't
normal. It will eventually cause damage or fire.

[PipeDown]

It is normal and as long as the arcing stays within the housing of the
switch it is also safe. Better switches than the cheapest "contractor
grade" have a better chance of not arcing but it still can happen because
thats what electricity does when a circuit is closed when a load is
connected. I bet it dosen't happen on switches that go to receptacles where
nothing is plugged in right now.

Now if it were a loud pop and the light flickered, then I would say go ahead
and replace the effected switches because the contacts have eroded due to
too much arcing.

<affili...@gmail.com> wrote in message
news:1150935124.7...@c74g2000cwc.googlegroups.com...

[RayV]

I put in the cheapos from the depot and can see a spark when I flick on
a light in the dark, you have to be at the right angle to see it. Yes
I have cover plates on.

[RBM]

It is normal. All standard wall switches under load will cause an arc when
making and breaking. In most cases it's small and not noticeable. If its
hissing , crackling,or sparks coming out of the switch body, then change the
switch

<affili...@gmail.com> wrote in message
news:1150935124.7...@c74g2000cwc.googlegroups.com...

[hal...@aol.com]

flash spark normal....

cheap white or biege switch, with cheap cover plate.

just forget about it

[Toller]

"RayV" <Nunya...@comcast.net> wrote in message
news:1150936747.1...@g10g2000cwb.googlegroups.com...

If you say so. My house has "contractors" switches, and I have never seen
an arc.

[mm]

On Thu, 22 Jun 2006 00:18:25 GMT, "Toller" <Tol...@Yahoo.com> wrote:

>
><affili...@gmail.com> wrote in message
>news:1150935124.7...@c74g2000cwc.googlegroups.com...
>>I am wondering if this is normal. I can see flashes of light sometimes
>> when I flick on various light switches around the house. It's
>> intermitent but most noticeable at night when there is little light in
>> the room. I am nervous this is going to start a fire. Spoke with the
>> developer they said it's normal. Any thoughts?

I think God is talking to you. Pay close attention to the lights and
you will understand what he is saying.

>This has to be a troll. Even the worst arc wouldn't be visible with a
>switchplate in place.

No, it's visible through the lever part of ivory colored switches,
especially if it is dark in the room and the switch turns on something
that is not a light or something in the other room. Would God do
this if no one could see it?

>But just in case it isn't; no, a significant arc when using a switch isn't
>normal. It will eventually cause damage or fire.

These are little arcs. I think they're normal.

[Steve in Virginia]

Question: How old is your house?

If it was built in the 70's you might be dealing with aluminum wire.
You could also be dealing with aluminum wire and a light switch rated
for copper, instead of switch with a CO/ALR or the older Al/Cu rating.
Aluminum wire is notorious for loosening because of the warm-cool
cycles with use. If the connections loosen sufficiently they will arc,
and in some cases (like in our bedroom) quite spectacularly.

Steve

[Chris Lewis]

According to Steve in Virginia <chandl...@hotmail.com>:

Aluminum isn't going to make any difference with switch contact arcing.

Minor, sometimes visible (especially when dark at particular
angles) arcing is normal.

_All_ mechanical switches arc. The real question is "how much?"

Seeing it "through" some of the plastic isn't altogether abnormal either -
depends on the plastic.

If you can hear more than a slight snap, or makes prolonged noises/sizzles
etc, produces any visible smoke or smells of ozone, replace it.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.

[mm]

On Thu, 22 Jun 2006 18:03:07 -0000, cle...@nortelnetworks.com (Chris
Lewis) wrote:

>
>_All_ mechanical switches arc. The real question is "how much?"

Evem "arcless" mechanical switches arc. But the whole mechanism is
submerged in oil, so flammable gasses can't get into the switch and
ignite, and then ignite what is outside the switch.

[t]

I believe you this is happening behind a switch in my basement I can see it when the lights are off at night looking down the stairs it flickers over and over. It is a bit worrying but I’m assuming it’s been that way and I just happened to notice now.

--
For full context, visit https://www.homeownershub.com/maintenance/electrical-flash-behind-light-switch-plate-121693-.htm

["\"Re...@home.com]

On 11/20/21 12:01 PM, t wrote:
> I believe you this is happening behind a switch in my basement I can
> see it when the lights are off at night looking down the stairs it
> flickers over and over. It is a bit worrying but I’m assuming it’s
> been that way and I just happened to notice now.
>

Original post at Homemoaners is 15 years old.

New poster, are you sure this is not a switch with a built-in neon
"night light". Neons of this type tend to flicker when on.

If not, then you need to have it investigated by an electrician.

[micky]

In alt.home.repair, on Sat, 20 Nov 2021 12:17:27 -0500,

In the old days, switches were mechanical and made a very noticeable
click. But by the 50's there were also silent switches, which I think
used a capsule of mercury to turn on and off (Since thermostats used
mercury, I assume light switches did too.)

But in the last 40+ years, all the new switches are quiet, they have
little or no detent when going from on to off or vice versa, and I think
mercury is seriously discouraged.
So what is the method of switching inside?
Have they gone back to mechanical but eliminated/without the spring
and the detent?


I used to take them apart but only when they were broken, and I've been
here 38 years and nothing has broken.

[gfre...@aol.com]

On Sat, 20 Nov 2021 17:28:59 -0500, micky <NONONO...@fmguy.com>
wrote:

It is a sliding contact instead of a "snap switch" although that is
still the trade name.
I will break one if you want to see inside.

[Clare Snyder]

On Sat, 20 Nov 2021 12:17:27 -0500, "\"Retired"@home.com wrote:

>
>

Neon will be an orange-red flicker. Electrical arcs tend to be
blue-white

[Clare Snyder]

On Sat, 20 Nov 2021 17:28:59 -0500, micky <NONONO...@fmguy.com>
wrote:

No mercury in silent switches - they just went to a softer detent
and a different type of contact. The old snap switches were rated
almost the same for DC as AC. The new silent ones have a VERY LOW DC
rating because they open and close much more slowly

[TimR]

It seems likely to me that you get more arc when whatever your load is has a significant reactive power factor.

When most loads were an incandescent bulb you probably didn't see much. With LEDs, CFLs, computers, etc. there is likely more.

[bud--]

I vaguely remember long ago some early silent switches had mercury.
Ancient history.

Snap switches use an "over center" mechanism with a spring to force the
fast action. "Microswitches" also use an over center mechanism. There
are some high amp (1000+?) disconnects that use an over center mechanism.

Silent switches use the AC zero crossings to break the arc.

In high school the 50A dimmers on the stage had tiny toggle switches and
switching was very quiet. The contactors had a tube with mercury. When
switched on a solenoid pulled a floating iron cylinder down into the
mercury, which rose to contacts.

[Clare Snyder]

There MAY havebeen a few "early" silent switches - but very few -
and they wouls not work if installed any way otherthan straight
right-side-up vertical. Also, silent switches do NOT use "zero
crossing" as they have no electronics in them. They use a simple
"spring lever contact"- like a set of ignition points with a lightly
spring loaded detent.

The "snap" switches DID use an over-center "knife" switch that
"jumped" open or closed in a millisecond or two.

[Bob F]

I think the idea was that at zero volts the arc stops.

>
> The "snap" switches DID use an over-center "knife" switch that
> "jumped" open or closed in a millisecond or two.
>

And then, there are relays for DC with magnets to blow out the arc.

[gfre...@aol.com]

Clare described them well.
This is 2 styles opened up. The toggle cams the strap with the contact
down against a pretty stiff spring to pop it open when you turn it
off.
http://gfretwell.com/electrical/Snap%20Switch%20.JPG

I agree any arc from any load the switch is rated for will break on
the zero crossing. That is why some say incandescent load only and
others have HP motor ratings.

[bud--]

Yes. The silent switch action is relatively slow and there will be
multiple zero crossings. Slow action is why the DC rating, if any, is
far lower than the AC rating, as Clare said.

>>
>>>
>>> The "snap" switches DID use an over-center "knife" switch that
>>> "jumped" open or closed in a millisecond or two >>>

But not necessarily a "knife" switch

>>
>> And then, there are relays for DC with magnets to blow out the arc.

AC contactors may have multiple horseshoe shaped iron pieces around
where the arc will be (arc chute). The arc current creates a magnetic
field in the pieces that lengthens the arc - blow out.

Haven't seen DC contactors, but I suspect the construction is similar.

>
> Clare described them well.
> This is 2 styles opened up. The toggle cams the strap with the contact
> down against a pretty stiff spring to pop it open when you turn it
> off.
> http://gfretwell.com/electrical/Snap%20Switch%20.JPG
>
> I agree any arc from any load the switch is rated for will break on
> the zero crossing. That is why some say incandescent load only and
> others have HP motor ratings.
>

From the UL White Book
"SNAP SWITCHES (WJQR)
AC GENERAL-USE SNAP SWITCHES [probably includes all the silent switches]
AC general-use snap switches are tested for the control of resistive,
inductive (including electric discharge lamp) and tungsten-filament lamp
loads at 120 V up to the full current rating of the switch, and for
motor loads up to 80% of the amp rating of the switch, but not exceeding
2 hp."

Any garden variety AC-only wall switch should have the HP rating.

UL testing (1991 version) included:
10,000 operations with an incandescent light load [inrush greater than
rated current]
Also testing similar to closing on locked rotor current for a motor at
80% of amp rating.
And quite limited number of tests for opening on locked rotor current
for a motor at 80% of amp rating.
A motor was not used, but an equivalent load including inductance.

[TimR]

On Monday, November 22, 2021 at 10:14:22 AM UTC-5, bud-- wrote:

> >>
> >> I think the idea was that at zero volts the arc stops.
> Yes. The silent switch action is relatively slow and there will be
> multiple zero crossings. Slow action is why the DC rating, if any, is
> far lower than the AC rating, as Clare said.

I vaguely remember debounce circuits being required in some designs (in the equipment, not the switch) because most switches have at least some multiple events, and if timing is critical it has to be prepared for.

I can't remember an example though.

[gfre...@aol.com]

You are typing on one.

[micky]

In alt.home.repair, on Sun, 21 Nov 2021 23:48:31 -0500, Clare Snyder

Around 1960, there were as many silent switches as people chose to buy.

We might have bought one or two except we didn't have any broken
switchers to replace, the noise of the current switches weren't
bothering anyone, and the silent ones were more expensive.

>and they wouls not work if installed any way otherthan straight
>right-side-up vertical.

So what. 99+% off all these 110v toggle switches are mounted that way
anyhow. I think I put one in my model train platform that was
horizontal but's the only one I can think of.

> Also, silent switches do NOT use "zero
>crossing" as they have no electronics in them. They use a simple
>"spring lever contact"- like a set of ignition points with a lightly
>spring loaded detent.

The silent swtiches I refer to had no detent.

[gfre...@aol.com]

On Sun, 28 Nov 2021 05:55:06 -0500, micky <NONONO...@fmguy.com>

Back in the 40s and 50s rich people did have mercury switches that
were completely silent and smooth operating because it was just a tube
of mercury with a couple of contacts in it. They were several bucks
each at a time when Porterhouse steak was 59 cents a pound.
These days a silent switch is just a pair of contact points cammed
together by the toggle handle.

http://gfretwell.com/electrical/Snap%20Switch%20.JPG

They are still called snap switches in the code and the trade even
though there is not much snap in them.

[Clare Snyder]

On Sun, 28 Nov 2021 05:55:06 -0500, micky <NONONO...@fmguy.com>

I meant to say there may have been a very few "early" silent switches
that used mercury - but very few

>
>Around 1960, there were as many silent switches as people chose to buy.
>
>We might have bought one or two except we didn't have any broken
>switchers to replace, the noise of the current switches weren't
>bothering anyone, and the silent ones were more expensive.
>
>>and they wouls not work if installed any way otherthan straight
>>right-side-up vertical.
>
>So what. 99+% off all these 110v toggle switches are mounted that way
>anyhow. I think I put one in my model train platform that was
>horizontal but's the only one I can think of.
>
>> Also, silent switches do NOT use "zero
>>crossing" as they have no electronics in them. They use a simple
>>"spring lever contact"- like a set of ignition points with a lightly
>>spring loaded detent.
>
>The silent swtiches I refer to had no detent.

Without a "detent" they would not stay in the position you put them
in unless they used a "friction break" - but without a detent they
could sit half way between on and off, arcing (in the mercury bulb?)
causing the switch to fail quickly. Virtually ALL switches have a
"detent" of some sort.

>
>>The "snap" switches DID use an over-center "knife" switch that
>>"jumped" open or closed in a millisecond or two.

And I'll correct myself here before Micky or someone else does - not
ALL were "knife" switched - some were not a wiped contact but they
WERE over-center "snap" switches that DID open and close extremely
quickly compared to a "silent"switch

[micky]

In alt.home.repair, on Sun, 28 Nov 2021 16:30:32 -0500, Clare Snyder

I can't remember the last time I argued with you. ;-)

[Marilyn Manson]

Back in the early 80's I moved into an apartment with the loud snap
switches. I bought a bunch of silent switches and replaced them all,
putting the loud ones in a closet.

2 years later I bought a house with the loud snap switches. Before I
moved out of the apartment, I swapped the loud ones back in and
used the quiet ones in the house.

Part of me said "They are mine, I'm taking them with me" and part of
me said "I don't want them knowing that I was messing with wiring." I
doubt the "upgrade" would have impacted my security deposit, but
why take the chance?

[micky]

In alt.home.repair, on Mon, 29 Nov 2021 15:10:03 -0800 (PST), Marilyn

When I moved in here, the shower head was surely the original one, but I
thought it didn't have enough water. Somehow I already had a nicer one
and I put it on. I'm planning to change back before I leave so I can use
the good one at the nursing home I end up in.

>
>Part of me said "They are mine, I'm taking them with me" and part of
>me said "I don't want them knowing that I was messing with wiring." I
>doubt the "upgrade" would have impacted my security deposit, but
>why take the chance?

Some landlords would complain, I think, and you don't know in advance
which ones. I think on the People's Court I've seen landlords complain
about what anyone would call an improvement.

When I lived in NY, the bathtub drain was outside the tub, a separate
pipe in a pipe as high as the water level in the tub was allowed to be.
When you lift the plunger, the inner pipe, the water drains right at
floor level. I taped up the overflow holes in the top of the plunger
(which were much bigger than the ones in the video) so I could fill the
tub another 2 inches, and then I could float with only 2 or 3 square
inches of my rear end touching the bottom. I was afraid I would forget
to untape it when I left but I didn't forget.

Mine was prettier, brass with a white ceramic knob on top. I didn't know
what it was when I first moved in.
https://diy.stackexchange.com/questions/46954/how-does-an-external-tower-style-bathtub-drain-work

https://www.google.com/search?client=firefox-b-1-d&q=standing+waste

https://www.youtube.com/watch?v=ZHM4Ttuqd3Y

Much too long, 24 minutes:
https://www.youtube.com/watch?v=eRKjoOkl_Q4


Here in Baltimore, I took the overflow for the tub and turned it upside
down. I think this gives me one inch more depth. This change is
obvious from the outside and the tub needs remodeling anyhow, and these
overflows seem insufficient anyhow, but I do plan to put it back the way
it ws.