Using 3-way switches as a 4-way

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.
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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.
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Intermatic makes a Decora single-unit timer module (also a switch) 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

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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.
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I think someone is blowing smoke up your...

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four
done
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.
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
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any chance you still have that book? and could scan the article. I would like to add it to my collection
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that
The
really
would
Sorry, I don't have the set. It was my parents' from when they got 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&item582755746&category (666
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?
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snipped-for-privacy@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

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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.
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snipped-for-privacy@aol.com says...

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 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?
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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.
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snipped-for-privacy@aol.com says...

I said it was ugly, but possible. ;-)
I also don't see the safety issue (thus why would UL care?).
--
Keith


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"Keith R. Williams" wrote:

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.
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snipped-for-privacy@bellatlantic.net says...

Are you saying that the inspector will supercede his authority 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

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"Keith R. Williams" wrote:

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.

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snipped-for-privacy@bellatlantic.net says...

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

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"Keith R. Williams" wrote:

No, Keith, that is NOT what I am saying.

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

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.

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snipped-for-privacy@bellatlantic.net says...

Yes, it essentially is.

Why? Everything on the stitch side is at the same potential, or an open.

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.

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 theyre not paid enough to do it).

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.

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.

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.

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.

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

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"Keith R. Williams" wrote:
<snip>

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>
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