Faulty 3-Way wiring


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Old 08-04-06, 07:00 PM
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Faulty 3-Way wiring

I have recently moved into an 18-year-old house and have been doing some remodeling. I noticed a consistent wiring technique on all of the 3-way light switches in the house that has me troubled and baffled.

1) After turning of the breaker servicing a receptacle I disconnected the wires in a receptacle and noticed the lights in the room (3-way) went out.
2) Investigating further I realized that other receptacles in the room were reading “HOT/GND reverse” on my “cheapy” tester.
3) To see what was going on, I reconnected the receptacle I was working on and turned the breaker back on and the lights functioned normally. Strangely enough the receptacles indicating “HOT/GND reverse” now were showing “CORRECT”.

My conclusions (rightly or wrongly) are that I have faulty wired 3-ways and separate breakers feeding the same circuit. Since this is a two-story home, I have virtually no way of running additional wiring to fix this mess. Does anyone have suggestions of what I can do to be both safe and functional?

Thanks,
Matt
 
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Old 08-04-06, 08:06 PM
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It is possible you have a double feed, but my bet is on phantom voltage tricking your tester. You can check the actual voltage, if any, with a meter at the receptacle to see how much it is. Most likely will be about 30 volts, but still phantom voltage.
Post back with results of a metered check.
 
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Old 08-05-06, 09:53 AM
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Hot grnd reverse is an indication of an open neutral. It is possible this is a multiwire circuit. It could take two breakers to kill all the power to this circuit.
 
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Old 08-06-06, 09:24 AM
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I agree with Joed. The receptacle you removed was part of the return (neutral) path for the receptacle that read "Hot/Gnd Reverse".

If the lights are on the same circuit as the "Hot/Gnd Rev." receptacle, then they would go out as well, without the neutral in place.
 
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Old 08-07-06, 10:52 AM
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A little more info, and a question

Everything you guys said is right on. The lights function correctly as long as all wires in both circuits are connected. In addition, the hot/neutral condition goes away as well.

Since it appeared to have something to do with 3-way light switches, I checked other locations in the house that had 3-ways and they were all wired the same way. It looks like what happened is the original electrician didn't want to send a 3 conductor (plus ground) from one switch to the other. Since he only sent a 2 conducter (plus ground) there was no neutral return from the switch that wired the light. He simply used another (close by) neutral to do the job instead. What a way to save a few bucks!


My question for the experts is this:

Since this has occurred all through the house and none of it can be fixed easily, do I really have a concern? I am now cognizant of the situation, so I will carefully check each conductor in a box I am working on even though I killed the circuit. My real concern is for potential fire hazard or something of that nature.

Thanks,
Matt

BTW – Is this an accepted practice of wiring 3-way switches or did this electrician fly under the radar of the inspector? Sharing a neutral in this manner just doesn’t seem to be a good idea.
 
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Old 08-07-06, 10:59 AM
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Have you verified that these are not multi wire circuits? Properly done multi wire circuits are safe. Improperly done, sharing a neutral is bad.


If the neutral is shared improperly then yes, you have a real concern. If the neutral carrying the return current gets overloaded (which it can do because it is not protected by a fuse or circuit breaker), then a fire could develop.

Please determine if a multi wire circuit is present or not. In other words, does the wiring leaving the panel for the shared circuits leave on a single 3 conductor cable (plus ground) or on two 2 conductor cables (plus grounds)?
 
 

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