3 way switch question

12 years ago

Hi Everyone:

I will try to make this as clear as possible but it might be long, so my apologies in advance!!

____________________________________________

I rewired one of the two old 3-way switches in my house recently but may have a problem.

The switch is setup S1--Light--S2 in a long hallway.

The switch I rewired was at the end of that chain (marked 's2' above). It had typical nm-3 cable with white, black, red, and ground wires present.

I wired it as per the instructions on http://www.acehardware.com/info/index.jsp?categoryId=1284746 (step #9) as that is what the situation appeared to be. I was too dumb to take a picture of the old switch and have since learned my lesson...so I followed the instructions above thinking it would be a simple job.

Anyways, long story short; red wire went to the black screw marked common, black and white wires to the other two terminals, and the ground to the green.

Problem is the switch in the beginning of that chain (S1) now must be on for the switch I rewired (S2) to function.

If S1 is turned to off, then the light wont go on or off when toggling S2. Conversely, if S1 and S2 are both on, and I turn OFF S2, the light goes off but now the first switch does nothing instead.

So basically I have a case of one switch doing nothing independently of the other one, and probably some crossed wires in there.

I'm guessing this is because my common wire is not actually the red wire, but one of the other two - is this the likely culprit? I do not know if the power is going to the switch or coming from the light, is there a way to tell using a volt meter?

MOST IMPORTANTLY, how dangerous is it to leave it like this for a few days? The switches are both turned 'off' (circuit panel is still on) and the house is unoccupied for a few days, so I'm mostly nervous about an electrical fire here. No sparking or smells or anything while I was there, but still pretty uneasy about it knowing something is mixed up.

I'd like to get an electrician in there next week if necessary but I just want some piece of mind the place isn't going to burn down in the meantime. Any thoughts?

Thanks for any help!

jay

Featured Answer

rubenmoore123

8 years ago

I'll be honest I didn't read your entire post, but the solution is simple. It sounds like you only have three conductors and a ground in the box you replaced. In this case the electrician sent the hot back to that switch box through one of the conductors in that single wire. Most likely the white or neutral wire. Try putting the white wire onto the common screw and see if that fixes it. Make sure you turn off the breaker first and test all of the conductors for power before sticking your hands all over them. A sure fire method to find out which conductor has been dedicated as a hot or common wire, would be to dismantle the first switch and see which wires are jointed together with the hots in that box. (I.e. if you see two or three black wires wire nutted together with a white wire, then that's the designated hot.) Your original electrician most likely pulled the conductor to the light from the wrong side of the circuit. To answer your question if it is dangerous....I wouldn't say it's "safe" to leave it how it is, but I have been on service calls a thousand times where the customer claims their three ways operated incorrectly for years without incident. If it's an older dwelling, the hots and joints may be made up in the box the light hangs from, in this case the solution will be the same. The only difference is you wont be able to see what wire is designated to send the hot back to the right side of the circuit by looking in the other switch box.. I would advise you to have an electrician rewire the switches eventually. Those neutrals are designated as neutrals to balance the load on the circuit. Designating one as a conductor is common practice, but imo is lazy and incorrect.

Comments (10)

lj987
Original Author
12 years ago
Well, after a little more reading it sounds like I just dead ended it, would you agree? Could there be another explanation?

Much better understanding of what is going on now, but I'd still like a little reassurance if anyone can let me know if there is / is not a problem here!
bus_driver
12 years ago
The first thing I would do is swap the red and black wires on the switch screw positions. See if that solves the problem.
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linesman
12 years ago
Hello lj987 :

Hope this helps

Let us know how you made out with your wiring project

Have A Nice Day

Linesman
lj987
Original Author
12 years ago
Hi Linesman:

Isn't there any danger or issues with putting the hot wire on the wrong terminal though?

What's the worst that could happen if the wires on this switch are are wired to the incorrect terminals and I switch it on - is it like I blow a fuse/trip the breaker bad; or is it I get the shock of a lifetime bad?

Thanks!
bus_driver
12 years ago
Amazing!!! lj987 had no concerns about the wrong wire when he/she was doing the switch change out. But is concerned about the requested responses. And apparently has not put into action any of the advice offered. I keep asking myself why I even bother to try to help people who ignore advice given. Neither my suggestion nor that of the linesman will create any problem. My next suggestion is to call an electrician.
linesman
12 years ago
Hello lj987

If you turn OFF the breaker before you move the
wires one screw clockwise you will be OK.. There will be no sparks when you turn the breaker back on..or while your flipping
the switch(s) up and down.

Hope this helps

Let us know how you made out with your wiring project

Have A Nice Day

Linesman
hendricus
12 years ago
Isn't there any danger or issues with putting the hot wire on the wrong terminal though?

Well, after a little more reading it sounds like I just dead ended it, would you agree?

Yep, that's all you are doing till you follow directions given.
lj987
Original Author
12 years ago
bus_driver;

I asked twice if there was any danger in my initial two posts and you did not respond to those concerns. I also stated that I am not at the property currently and thus, have not put any of the suggestions into action.

Simply telling someone to switch wires based on color when it's unknown what is being used as the common and hot sounded pretty sketchy to me, especially when one individual suggests moving the black wire and the other one suggests moving the red.

My apologies for this concern, I DO appreciate everyone's advice, and am glad to know now that it will not cause any problems or pose any threats should the wrong wires be in place at the wrong terminals. As someone trying to learn as much as they can about simple wiring I think safety should be paramount, especially as this was a mistake on my part, and I hope you can sympathize with my initial concerns.

I will make the changes this weekend and report back.
lj987
Original Author
12 years ago
I considered myself lucky for not having problems with the initial wiring, and am trying to be safer / much more educated on what I'm doing the second time around, hopefully learning my lesson and gaining an understanding of what's actually going on here instead of relying on wire colors.

Thank you all for your advice and response.