Stray voltage

[Handyman John]

I am an above average handyman / do-it-yourselfer. I have run new circuits, and done a lot of basic wiring. I encountered something yesterday that I don't understand and have not seen before. I was re-wiring my ceiling fan with a 3 wire plus ground feed in place of the existing 2 wire plus ground in order to seperate the light and the fan to seperate wall switches. There were 3 sets of 2 wire with ground at the existing switch. The feed came into the bottom of the switch to a screw terminal. The feed to the ceiling fan came out the top of the switch. There was another feed coming out the bottom of the switch. The 3 commons were tied together in the box, as well as 3 the ground wires. Everything was going along fine. I had the breaker shut off and had checked the supply line and it was off. As I was disconnecting the wires from the switch and unhooking the common wires, I got shocked. I tested the lines and found that one of the commons had 46 volts on it. I determined this common went with the black wire that came out of the bottom of the switch. I went to the attic and found that this feed went to a wall switch that controls the hallway light fixtures. It is a setup with 2 fixtures that are controlled in a three way configuration from either end of the hallway. I called a friend who is a maintenance supervisor and he told me that this happens if you have a loose connection somewhere or you may have a slight short. I checked all connections in the breaker box, but the problem still existed. I pulled my new cable and hooked up the fan. With the breaker still off, as I tied the commons together, I got a spark from the offending common and the hallway light came on. When we flipped the hallway switch, the light went off and the spark went away.

Can anyone explain what may be going on here and how I should go about troublkeshooting the problem?

[Rewired]

Question: that 2-wire that goes to the 3-way switches , the one thats causing problems, where is the "hot" connected to at the other end??
It sounds like 2 different circuits are present somewhere in a box (which shouldnt be by code) and someone has crossed the neutrals.. its hard to say really.
I would start by finding where the feed for the hallway lights originates, and tracing it step by step, ( from hot to the common on the 3-way, down the travellers, to the other 3-way, out the common, to both lights, then from the lights to the same neutral where the feed originates, no where else)
I think you may find a crossed neutral somewhere in one of the boxes possibly..

A.D

[kactuskid]

I agree with the part about a separate circuit is present in this box, but, it is not illegal to have 2 different circiuts in the same box. What is illegal is that these 2 different circuits are tied together in this box. I'm guessing that you have a power feed to the 3 way light circiut comming from either the light fixture or the other 3 way switch.

These 2 circuits cannot and should not be tied together in the electrical box. The neutrals and hots must remain separate. The grounds from both circiuts entering the same box should be tied together though. Try turning on your hall light, now find out which breaker controls this circiut. If it is a different circuit than the now you were working on with your fan, then separte them, and figure out why the line feeds from your switch to the hall switch, somethings goofey.

[Handyman John]

I spent the evening doing just what has been suggested. I still have some work to do in order to confirm my suspicions, but as of now, here is what I think is happening:

The feed from the fan circuit is going to the three way switch to the hallway. The black is plugged into the bottom back of the switch. At the same time, a feed is coming from one of the bedrooms into the same 3 way switch (confirmed I have 120 v between the black and white of this feed. The black is hooked into the screw at the bottom of the switch. The commons (whites) for these 2 feeds are tied together with a wire nut. Next, they have run a 2 wire (black and white)from the top terminals on the switch that look like they run to the other 3 way switch. I think this is part of the problem. Instead of using a three wire between the switches, they used 2 double wires and they got mixed up. In the second 3 way switch box, the white and the black come in from the other switch and are attached to the terminals at the top of the switch. There is a black wire feeding the lights. The white associated with this black is tied to another white with a wire nut. The black associated with that white is just in the box, not tied to anything.

What I am planning to do, (once I validate what I suspect) is to disconnect the feed wires coming from the fan circuit. Disconnect those wires from the first 3 way switch. Attach the black from the bedroom feed to the feed terminal of the 3 way switch. Run a 3 wire set between the switches (just temporarily down the hallway), black and red between switches, white connected to white from bedroom feed. At the second 3 way switch box, connect the red and black coming from the other switch to the top terminals. Attach the black that leads to the light fixture to the bottom terminal of the switch. Connect the white from the light feed and the white from 3 3 wire. See if this works and check voltages all around. If it works, physically remove the wires between the fan switch and the first 3 way, fish the 3 wire between the 2 switches, button everything up and call it a day.

Then my attention will go to every other 3 way circuit in my house to see how screwed up they are. Does this sound like a good approach?

Thanks for the good responses. Sometimes the advice from folks like you really solidifies the ideas or intuition that us do it yourselfers have. Thanks again

[kactuskid]

There are multiple ways a 3way circuit can be designed. First make sure you're familiar with how they work. 3way switches have a common (dark screw) screw and the two brass colored screws are for the travelers. These screws are not always in the same location for every 3way switch, so the top screws need to be looked at for their color and not their location.

You first need to know what wire the power comes in on. This wire will always go to the common screw of one switch. The common screw of the other switch will always go to the light fixture. This is always true unless the power comes into the circuit from the light. To find this out you will need to lable and remove all the wires from both switchs, spread them out so they're not touching each other and then close your breaker and test to ground for which wire is supplying your power.


Here's a bunch of links that'll give you details of how a 3 way circuit works and the different connection methods. Let us know what you find out.

http://www.danswiringpage.com/switches.htm

http://www.homewiringandmore.com/switchoutlet/3way/3way.html

http://www.the-home-improvement-web.com/information/how-to/three-way-switch.htm

[Rewired]

WOW!!!
Please let us know how you make out with everything eh! I think it will be an easy fix once you figure out what goes where and get whatever cables you need pulled into the wall. GOOD LUCK!!!!
Instead of looking at only the 3-ways in your house, I would take a look at [u]everything</u>, just to make sure the person that wired the place originally didn't mess up elsewhere that could cause you a problem down the road.

A.D

[Handyman John]

OK, as usual, things are not quite always what they seem. I did get everything wired properly last night and everything works well, but there were a few twists. Physically, the layout of the wiring components is as follows:

The switch box for the ceiling fan is in a bedroom on the west side of the house. There is a switchbox for the hallway lights right on the other side of the wall from the fan switch. The other hallway switch box is at the east end of the house. I shut off the breakers from the 2 circuits involved and disconnected all the wiring. I determined that the power for the hallway lights was coming into the east end switch box and was being fed from a circuit that also controlled lighting in a bedroom at that end. I determined that one 14-2 w/g was being used for the loop between the switches. There was another 14-2 w/g in the east end box, which I assumed was being used as the common somehow for the three way switch since they did not use a 14-3 w/g between the switches. They used oversized plastic boxes and as such, had wire staples holding the wires to the studs up above the boxes. Not knowing exactly what I had, I did not wanty to just start pulling wires out up in the attack, because i was afraid that I might pull something that was good and end up damaging it. So, I ended up breaking the plastic boxes out to get a better idea of what I had going where and to get access to the wire staples that I needed to pull out. When I broke the box out at the west end hallway box, there was a a black and white (no ground) sticking through the wall from the fan circuit. This is where the white was tied in and the black was just there. It suddenly started to make sense. Sincer they only ran a 2 wire w/g between the switces, they did not have a common. Instead of running a common between the hall switches, they just ran one from the ceiling fan box. That is the one that kept biting me. I pulled that out, and determined whick wire set was the one running beyween the switches. I puleed that out and fished a 14-3 w/g in it's place. I figured out the extra wire set in the east end box was a feed to a hall closet light on the hallway/bedroom light circuit. Anyhow, I took metal boxes, drilled a couple holes in the side and screwed them into the studs. I hooked up the wiring and everything worked. I put it all back together and now just have to do a little drywall patching since the metal boxes were smaller than the plastic ones I knocked out.

Thanks for all the advice.

[Handyman John]

As far as relloking at everything, I concur with your assessment. This is not the first rewiring I have had to undertake. I found out the hardway that all the GFI outlets in the house other than the kitchen were on one circuit. From one bathroom to the other bathroom to the front porch to the back porch to the freezer in the garage to an outlet on the wall on the other side of the garage. One night during Christmas season, with outdoor lights running and my wife using hair dryer in bathroom, the circuit went out. I was asleep and she did not know how to reset it, so she just went to another outlet to dry her hair. When I got up to go to work the next morning, she was not awake yet. When i came home that evening, she told me what happened. So I reset the GFI and then started looking at why it tripped. You guessed it, I found the freezer with a nice little puddle on the garage floor. I spent the weekend unhooking connections one at a time to see what the flow was and then added a couple more circuits and split the offending outlets among those circuits. So, I expect I'll find more issues. I feel like the handymen from Green Acres did the wiring !!!!

[mrcaptainbob]

Well, the guy that wired your place had a brother that worked on mine! I had a similar situation. The front half of the house was on ONE breaker! 1.5 baths, master bedroom, foyer,garage, basement sump and of all things too, the KITCHEN! The rest of the panel was divided between a family room, living room and two bedrooms. Oh yeah, and the one plug outlet on the back wall of the garage. We closed on that house today. I feel like I just about had it all done the way we needed, and here we go and sell it!!?

[Rewired]

Is "Green Acres Electric" associated with "Hack 'N Slash Electric" up here in Canada??? I was in the basement of a variety store a few months back,and they had all the new circuits to all the coolers upstairs just laying on the floor, they had circuits to lights just wired with lampcord and in some cases individual pieces of single wire strung through the joists or tied to nails, but what took the cake was this one 3-way switch... it had one 14/2 cable entering the box... When we took it apart we found they used the bare as one of the travellers!! The odd thing is no one got a shock off the metal switch cover, and at the other end where the "bare traveller" went into a properly grounded box, someone took the time and care to make sure it didn't touch ground!!
If only they took time and care to wire the place right the first time!!!

A.D

[mrcaptainbob]

Seems like this thread is turning into one about "electrical horror stories"!