Using 3-way switches as a 4-way
reactancexl
way. How is that wired? I always use a four way, but I think it is done
for cost reasons.
Harry Bloomfield
> I heard some contractors hooking up three 3-way switches instead of a four
> way. How is that wired? I always use a four way, but I think it is done
> for cost reasons.
For what exactly?
--
Regards,
Harry (M1BYT)...
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SQLit
"reactancexl" <react...@cox.net> wrote in message
news:nTtRb.635$IF1.517@fed1read01...
> I heard some contractors hooking up three 3-way switches instead of a four
> way. How is that wired? I always use a four way, but I think it is done
> for cost reasons.
I for the life left in me do not understand what you are talking about.
3ways are used in pairs to switch from 2 locations.
4ways in the middle of the circuit add another location depending on the
number of 4 ways.
I await the lords of electricity to explain this one.
Are you sure someone is not pulling your leg?
Mike Lamond
showed
how to wire _two_ three-way switches to work as a four-way switch. The
handles
were ganged by runnning a screw through them to make the switches
operate
together. Electrically, you have same thing, but I don't think it really
meets
code.
What the contractors may have been talking about is rearranging a
lighting
circuit with three or more switches into several circuits with only two
switches on each one. Why they might need or want to, I have no idea.
Mike
indago
Maybe he's thinking on the basis of two 3-ways make a 6-way...
Keith R. Williams
news.ops.worldnet.att.net>, m.ABC...@XYZworldnet.att.net says...
>
> "reactancexl" <react...@cox.net> wrote in message
> news:nTtRb.635$IF1.517@fed1read01...
> > I heard some contractors hooking up three 3-way switches instead of a
> four
> > way. How is that wired? I always use a four way, but I think it is
> done
> > for cost reasons.
> >
> >
> I remember an article, in a 1960 vintage homeowner's encyclopedia, that
> showed
> how to wire _two_ three-way switches to work as a four-way switch. The
> handles
> were ganged by runnning a screw through them to make the switches
> operate
> together.
Sure, simply gang two SPDT switches to make one DPDT switch:
o o
| |
| |
+--------|---+
| | |
| +----+ |
| | | +
+ + + |
o /o o /o
/ /
/--------/
o o
| |
| |
o o
created by Andy´s ASCII-Circuit v1.22.310103 Beta www.tech-chat.de
> Electrically, you have same thing, but I don't think it really
> meets
> code.
IANALEB, I'm not sure why it wouldn't meet code. There's no safety
issue that I can see. Kinda kludgy though.
> What the contractors may have been talking about is rearranging a
> lighting
> circuit with three or more switches into several circuits with only two
> switches on each one. Why they might need or want to, I have no idea.
OTOH, Any number of X10 "three way" switches can be ganged together.
They use one runner for power and the other for signaling.
--
Keith
Brian
"reactancexl" <react...@cox.net> wrote in message
news:nTtRb.635$IF1.517@fed1read01...
Brian
"indago" <elin...@earthlink.net> wrote in message
news:BC3C441D.5FBF%elin...@earthlink.net...
SQLit
"Mike Lamond" <m.ABC...@XYZworldnet.att.net> wrote in message
news:8uARb.122004$6y6.2...@bgtnsc05-news.ops.worldnet.att.net...
>
> I remember an article, in a 1960 vintage homeowner's encyclopedia, that
> showed
> how to wire _two_ three-way switches to work as a four-way switch. The
> handles
> were ganged by runnning a screw through them to make the switches
> operate
> together. Electrically, you have same thing, but I don't think it really
> meets
> code.
any chance you still have that book? and could scan the article. I would
like to add it to my collection
Johan Lexington
> way. How is that wired? I always use a four way, but I think it is done
> for cost reasons.
Use two 3-way switches on the beginning and end of the run and
switches in the middle will be 4-way. Otherwise, you can't do it.
Harry Conover
> way. How is that wired? I always use a four way, but I think it is done
> for cost reasons.
Beats the heck out of me.
As you probably already know, you need two 3-way (SPDT) switches to
totally control power to a load from two different locations. They
accomplish this dual control by selection which of two wires is
("runners"?) is currently in use.
To add additional switches requires that the runners be reversed as
determined by the settings of as many additional 4-way (DPDT)
reversing switches as desired at intermediate run locations.
A 3-way (SPDT) switch alone is incapable of reversing the runners.
Are you sure that what you heard wasn't that they were using three
4-way switches, rather than two 3-way and a one 4-way? This could
save the contractor money, at least if he was buying large quantities
of all the same type switch.
Harry C.
Keith R. Williams
SQLit...@cox.net says...
Easy. See my reply (threaded right above in my reader).
Basically it's making two SPDT switches into a DPDT switch.
Cross-connect the two "ends" of a DPDT switch and you have a "4-
way".
--
Keith
Greg
>Basically it's making two SPDT switches into a DPDT switch.
>Cross-connect the two "ends" of a DPDT switch and you have a "4-
>way".
A am not really sure why you would do this. 2 3ways can't be cheaper than 1
4way. I am also not sure where you would find a UL listed handle tie.
Keith R. Williams
gfre...@aol.com says...
> >Easy. See my reply (threaded right above in my reader).
> >Basically it's making two SPDT switches into a DPDT switch.
> >Cross-connect the two "ends" of a DPDT switch and you have a "4-
> >way".
>
> A am not really sure why you would do this. 2 3ways can't be cheaper than 1
> 4way.
Don't be so sure. 4-ways can be expensive (3-ways aren't $.49
either). THought I agree, it's stupid for other reasons.
> I am also not sure where you would find a UL listed handle tie.
I don't see why UL would care. There is nothing dangerous here.
Stupid, sure. Dangerous? ...at least I don't see it. Perhaps
you have a scenario where there is a danger?
Greg
you can get the double box, two 3 ways and the cover for much less and I am not
sure how you explain that duct tape and rusty nail handle tie to the customer.
Keith R. Williams
gfre...@aol.com says...
> Dale Electric will sell you a 4 way commercial grade switch for $6.80. I doubt
> you can get the double box, two 3 ways and the cover for much less and I am not
> sure how you explain that duct tape and rusty nail handle tie to the customer.
I said it was ugly, but possible. ;-)
I also don't see the safety issue (thus why would UL care?).
--
Keith
Mike Lamond
news:8sRRb.20594$F15.14745@fed1read06...
married and bought their first house. Over the years it got pretty
much beat up and was finally tossed out.
There's a 1962 edition, virtually identical, on eBay:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3582755746&category=28666
I'd forgotten earlier that the illustration showed the switched mounted
outside on a pole next to the driveway, with no weatherproof cover and
the happy homeowner reaching from his car to turn on the front porch
light. Code violations, anyone?
eh...@bellatlantic.net
It's not that UL would care. The inspector uses
UL (or other recognized testing group) listing
as a major factor in approving things. He/she
would not approve the use of 2 3-ways as a four
way, without UL listing. Whether you or I think
it is safe or not is irrelevant. And imagine
the poor homeowner who decides to replace
that "4-way". Many homeowners get into trouble
replacing a 3-way. This "wack-o" 4-way setup
would make it even worse.
Beachcomber
that has a single lead that can be used with a simple spst switch at a
different location. Thus, you can have 3-way operation in effect with
one less traveler wire. I believe the instructions for the timer also
indicate how to wire it up for three location control with one timer
and two three-way switches.
This might work for you if you're doing outdoor lighting or one of the
control points needs to be a timer.
The Intermatic model SS8 Decora Timer Switch also has a cool
"astronomic dial" feature so that your lights go on at local sunset,
whatever time of the year it happens to be.
Beachcomber
Keith R. Williams
eh...@bellatlantic.net says...
and require something that is not called for in the code? I know
some do; been there :-(. (A building inspector I had once was a
putz.) It's still wrong.
Note that I'm not saying it's a good idea. It'll look like hell
and there is no good reason to make such a kludge, but I don't
see anything about it make such a thing unsafe. "Unsafe" is all
code is worried about (the NEC is written in blood).
--
Keith
Greg
switch can be installed this way (NEC 110.3(B)) and if it is "suitable" (NEC
110.3(A)(1))
There is also the old catch all, NEC 90-4 that allows the inspector a lot of
latitude in what they accept if it isn't specifically addressed in the code.
Certainly a homeowner can do damn near anything after the inspector leaves but
he inspector does have a responsibility to see that the installation meets
certain minimum safety requirements and that it follows industry practice while
it is still on a permit.
eh...@bellatlantic.net
No. It does not meet code. No way the inspector is
superseding his authority to fail the thing when it
has been modified from its intended use and from
normal industry practice, and with unlisted products
used in the modification, and in a manner not included
in the manufacturer's instructions.
Keith R. Williams
gfre...@aol.com says...
> The inspector can simply ask to see the manufacturers instructions that say the
> switch can be installed this way (NEC 110.3(B)) and if it is "suitable" (NEC
> 110.3(A)(1))
It's installed in a 120V circuit according to recommended
practices. It's function should *not* be in the realm of the
electrical inspector. What the hell does he know?
> There is also the old catch all, NEC 90-4 that allows the inspector a lot of
> latitude in what they accept if it isn't specifically addressed in the code.
Latitude? There should be *no* latitude! Of course reading the
inspection nonsense here about arc-fault breakers and fire
alarms, it's no wonder we aren't all broke, or dead.
> Certainly a homeowner can do damn near anything after the inspector leaves but
> he inspector does have a responsibility to see that the installation meets
> certain minimum safety requirements and that it follows industry practice while
> it is still on a permit.
Fine. Leave the inspector to rule *BY THE BOOK*. He should have
no other option. Wierd switches are simply weird. Would you
have an installation with X10 switches failed because the
inspector didn't understand them on his 10 minute inspection?
Please. House wiring isn't rocket-surgery.
Let me repeat; it's a dumb way to wire things and I cannot
understand why one would do it this way. I don't see why it
should be illegal, immoral, or on down the line to an inspector
getting his hackles raised. Inspectors don't make the rules.
--
Keith
Keith R. Williams
So you're saying that the inspector is perfectly within his
rights to make up the rules as he goes along? The switches *are*
being used within their ratings and as designed. If the
inspector doesn't understand the logic, well...
Understand, I'm not saying this is a good idea. Rather, I'm
saying that an inspector has no business telling me how I use
switches that are being used within their design parameters, even
though it's unconventional. There *is* no safety issue here.
Yes, I've had an inspector that was a PITA. He cost me a couple
of grand that he had *no* business forcing on me (again not
electrical). Inspectors should go by the code, not their dreams
of what the code should be.
--
Keith
eh...@bellatlantic.net
No, Keith, that is NOT what I am saying.
> The switches *are*
> being used within their ratings and as designed.
The switches have a hole drilled through their
toggles, and the tie is a nail, a paper clip,
who knows - but it is not a listed product. The
switches are NOT designed to have a hole drilled
through their toggles or ganged in any other way,
nor were they listed or tested for ganging.
They have NOT been tested in the suggested configuration
to ensure that they do not create the invalid scenario
of A connected to B and C connected to B simultaneously,
due to one switching before the other:
A B
-----0-0-----
/
-----0 0-----
C D
They also have not been tested for the mirror image
of that - a connection from A to D simultaneous with
a connection from C to D
> If the
> inspector doesn't understand the logic, well...
>
The logic is this: the inspector understands that
if he approves this, he does so without the backing
of the manufacturer or any testing laboratory, or
standard industry practice.
He understands that he is negligent in enforcing
110-3 (a) 1 (see FPN quoted below), 2 and 8 and
110 (b) if he allows this. He understands that he
is failing to follow 90-7, which directs him to
look for alterations or damage to listed devices.
He understands that there is absolutely no need for
the modification, since standard listed parts are
available to provide the function achieved by the
jury rigging.
After all of that, whether or not he understands
the circuit logic is irrelevant. He has no valid
reason to approve the installation, and numerous
code reasons to fail it.
FPN: "Suitability of equipment use may be identified
by a description marked on or provided with a product
to identify the suitability of the product for a
specific purpose, environment, or application.
Suitability of equipment may be evidenced by listing
or labeling."
Yes, I understand (your paragraph below) that you
are not saying it's a good idea.
Keith R. Williams
Yes, it essentially is.
> > The switches *are*
> > being used within their ratings and as designed.
>
> The switches have a hole drilled through their
> toggles, and the tie is a nail, a paper clip,
> who knows - but it is not a listed product. The
> switches are NOT designed to have a hole drilled
> through their toggles or ganged in any other way,
> nor were they listed or tested for ganging.
Why? Everything on the stitch side is at the same potential, or
an open.
> They have NOT been tested in the suggested configuration
> to ensure that they do not create the invalid scenario
> of A connected to B and C connected to B simultaneously,
> due to one switching before the other:
> A B
> -----0-0-----
> /
> -----0 0-----
> C D
So what? Either the traveler is open or it's energized. ...and
who cares if two are energized momentarily? There is no
possibility of a short across the switch.
> They also have not been tested for the mirror image
> of that - a connection from A to D simultaneous with
> a connection from C to D
Again, who cares? The travelers aren't going anywhere. Even if
you short them no magic smoke will be released. THere is *no*
safety issue here.
Again, it's dumbness to the extreme, but you're going to have to
try a *lot* harder to try to convince this engineer that there is
a safety issue here. The only excuse I can see is that the
inspectors shouldn't have that job (which I can accept, given
they’re not paid enough to do it).
>
> > If the
> > inspector doesn't understand the logic, well...
> >
>
> The logic is this: the inspector understands that
> if he approves this, he does so without the backing
> of the manufacturer or any testing laboratory, or
> standard industry practice.
Nonsense! There is nothing on these switches that is beyond the
manufacturer's specs. There is *no* possibility of shorting the
hot/neutral/ground. ...at least no more than any other
installation.
> He understands that he is negligent in enforcing
> 110-3 (a) 1 (see FPN quoted below), 2 and 8 and
> 110 (b) if he allows this. He understands that he
> is failing to follow 90-7, which directs him to
> look for alterations or damage to listed devices.
> He understands that there is absolutely no need for
> the modification, since standard listed parts are
> available to provide the function achieved by the
> jury rigging.
I disagree. Are you stating that a 4-way switch cannot be used
as a 3-way? Come on! The switches are used in the live side.
There is *no* possibility of anything "bad" happening.
> After all of that, whether or not he understands
> the circuit logic is irrelevant. He has no valid
> reason to approve the installation, and numerous
> code reasons to fail it.
Sure. He has reason because he's dumb. There is nothing
inherent in the safety of such a lashup. If the inspector fails
such nonsense (they won't even look), I'd like to see the
justification. ...your cites don't do it for me, since these
switches *are* designed for this function, even if the logic
escapes the inspector.
>
> FPN: "Suitability of equipment use may be identified
> by a description marked on or provided with a product
> to identify the suitability of the product for a
> specific purpose, environment, or application.
> Suitability of equipment may be evidenced by listing
> or labeling."
These switches are designed for 120V lighting circuits. If I
decide to do some strange switching, so be it. I've seen wired-
ANDs (single-pole, multiple switches) too.
> Yes, I understand (your paragraph below) that you
> are not saying it's a good idea.
We understand that, then.
I *am* saying that such weird switching isn't dangerous in any
way. The inspector should just get out of the way. Heavy-handed
inspectors just piss me off! Safety is one thing. Rules for
rules sake, are less than useful. e.g. the discussion about
failing inspection for smoke detectors not on arc-fault breakers.
DUMB, DUMB, DUMB!
--
Keith
Greg
saving money on materials and labor will be a lot more.
Can you honestly say the CUSTOMER would stand for this ugly mess when there is
a perfectly appropriate switch available?
Even if the electrician could get the inspector to hold his nose and OK this,
the field manager for the general contractor would insist you get the right
part.
If not, I wouldn't buy a house from them because I would expect there were
other short cuts (and bribes for inspectors) taken in the construction.
Keith R. Williams
gfre...@aol.com says...
> This has really degraded to an exercise in silliness. To start with you are not
> saving money on materials and labor will be a lot more.
Agreed, but the specifics aren't my point. The devices *are*
used as designed, in perhaps an unusual circumstance, for
*whatever* reason. The reason (stupid, or not) should not be
reviewed by inspectors.
> Can you honestly say the CUSTOMER would stand for this ugly mess when there is
> a perfectly appropriate switch available?
Nope. But, the customer may want some funky switching. It
shouldn't be up to the inspector to tell the owner what he wants.
My issue is not about this particular screwy lashup. It's about
dumb (and over-zealous) inspectors. I've been there, as a home
owner.
> Even if the electrician could get the inspector to hold his nose and OK this,
> the field manager for the general contractor would insist you get the right
> part.
> If not, I wouldn't buy a house from them because I would expect there were
> other short cuts (and bribes for inspectors) taken in the construction.
That's not my issue. My issue is about the inspectors not
following the rules, and enforcing *obviously* stupid rules (like
arc-faults on smoke detectors, as has been reported here).
--
Keith
eh...@bellatlantic.net
"Keith R. Williams" wrote:
<snip>
>
> Again, it's dumbness to the extreme, but you're going to have to
> try a *lot* harder to try to convince this engineer that there is
> a safety issue here.
I wasn't trying to address it as a safety issue. I
dismissed it from our discussion as a safety issue
in my first post in the thread:
"Whether you or I think it is safe or not is irrelevant."
The entire thrust of my posts was about inspecting
the thing, and not once did I say the inspector
should reject it because it was unsafe. I pointed
out reasons that he/she would reject it with code
references: suitability for use 110-3 (a) 1 FPN and
110-3 (a) 2 and 8; modification of the product 90-7;
lack of manufacturer's instructions for using the
product the way you suggest 110-3 (b)
No more trying - I can't convince you. Sorry to
have wasted your time.
<snip>
Keith R. Williams
eh...@bellatlantic.net says...
>
>
> "Keith R. Williams" wrote:
>
> <snip>
> >
> > Again, it's dumbness to the extreme, but you're going to have to
> > try a *lot* harder to try to convince this engineer that there is
> > a safety issue here.
>
> I wasn't trying to address it as a safety issue. I
> dismissed it from our discussion as a safety issue
> in my first post in the thread:
> "Whether you or I think it is safe or not is irrelevant."
I understand that. My argument goes to the next level. How much
power should bureaucrats have? They have way too much, IMO.
> The entire thrust of my posts was about inspecting
> the thing, and not once did I say the inspector
> should reject it because it was unsafe. I pointed
> out reasons that he/she would reject it with code
> references: suitability for use 110-3 (a) 1 FPN and
> 110-3 (a) 2 and 8; modification of the product 90-7;
> lack of manufacturer's instructions for using the
> product the way you suggest 110-3 (b)
...and I disagree. The unit *is* used within its capability.
There is no possibility of a short (as someone suggested).
> No more trying - I can't convince you. Sorry to
> have wasted your time.
No, you've been arguing a different issue. I believe the code,
and inspectors by extension, should care only about safety. What
they "like" should have no bearing on the issue.
--
Keith
Ben Miller
news:MPG.1a8b7cb74...@enews.newsguy.com...
> Nope. But, the customer may want some funky switching. It
> shouldn't be up to the inspector to tell the owner what he wants.
> My issue is not about this particular screwy lashup. It's about
> dumb (and over-zealous) inspectors. I've been there, as a home
> owner.
> That's not my issue. My issue is about the inspectors not
> following the rules, and enforcing *obviously* stupid rules (like
> arc-faults on smoke detectors, as has been reported here).
But that is exactly the point. In order to prevent what you are talking
about, the Code calls for listed devices installed in accordance with
manufacturers instructions. This eliminates the need for inspectors to look
into every internal detail of every wired device. They just look for the UL
(or ETL) label, and how it is installed. If the inspector sees mechanical
modifications that are obviously not a factory installation kit, he or she
can rightfully suspect that there might also be electrical modifications or
damage (ie. was the switch affected by the drilling operation?)
It is better for them to follow a consistent set of rules rather than
individually evaluating every Rube Goldberg design that they find.
Ben Miller
--
Benjamin D. Miller, PE
B. MILLER ENGINEERING
www.bmillerengineering.com