Added light switch and voltage doubled

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Old 02-26-13, 01:08 PM
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Added light switch and voltage doubled

Older home wired in early 60's had a single existing ceiling light switch and an unrelated 110V wall outlet. Wanted to make outlet switchable.

Installed a duplex switch and transfered wiring from existing switch to one of the new duplex switches. Connected new length of romex to other light switch and ran to existing 110V outlet.

Just to check I had voltage I tested the switched outlet with 2 different testers and both show 220V. Didn't think this was possible. How can I correct back to 110V?
 
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Old 02-26-13, 01:33 PM
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Your house has a nominal voltage of 120/240v. The only way too get 240v on a receptacle is if you used two hots, one from each leg of the 240 going to your house instead of the neutral and one hot.

My best guess is the receptacle you used is on one leg of your 240 and the switch is on the other. A switch may have a white wire but a white wire is not always a neutral. In this case I'd be willing to bet you had a black and white wire on the switch. If so then it was a switch loop and the white was a hot that was not remarked hot as required by code.
 
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Old 02-26-13, 04:55 PM
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Well I've never tested the voltage at the light itself which has never been used. I just tested it and to get any power requires both switches on and I then get 120V. So I'm guessing what you suggested is correct. Seems like a lot of the non-appliance outlets are on one circuit and maybe one leg and maybe the lights are on the other leg.

I also believe the new switch must be faulty. If the outlets are on one leg and the lights on the other then I would think there has to be some fault in the switch itself to get 240V. The 2 switches of the duplex should be completely independent of each other.

In this case, as I mentioned previously, I transfered wiring from existing light switch to one of the new duplex switches. When I turn only that new switch on I get nothing and when I turn only the other switch on I get nothing but when both are on I get 120V. So its all messed up.

I'm not sure how delicate the internal workings of currently made switches are but it may be possible it got damaged when it was installed. It got a bit tweaked and I noticed the switch body opened a bit along where 2 pieces came together. I removed and thought I had straightened it up but maybe not.

I'll buy another switch and try again. This is a pretty simple task. Even though lights may be on one leg and outlets on the other I should be getting only 120V at either switch. I'm not sure how safe that is or how it is regarded by code to have ability of 240V in one box that should only be 120V max. But the wiring in the house is what it is and I'll just have to work with it that way.
 
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Old 02-26-13, 05:32 PM
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added light switch

If you want to have 2 circuits on a duplex outlet. you need to break the brass "tab"connection between the "brass" terminals so that the 2 hot lines are seperated. You only need 1 (usually the white) return line. I hope this helps.
 
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Old 02-26-13, 05:34 PM
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A broken switch would never produce 240 volts if properly wired. It is not the switch. Did you break the tab between the two switches?
 
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Old 02-27-13, 11:09 AM
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I'm just stabbing at stuff here to understand whats going on so I can fix.

Going by what was said earlier. If a hot wire from each leg of service was connected to a separate switch in the duplex and there was some kind of fault in the switch seems that would be only way to get 240V which I have at the outlet. Should be 120V.

As I mentioned earlier, both switches need to be on in order to have power (120V) at light but light is only wired to one switch. There is a tab on outlets which can be removed but on a duplex switch I don't believe so.

Attached is what I came up with for a schematic. Maybe there's a problem there?
 
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Old 02-27-13, 11:54 AM
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Nice diagram and it looks correct. Again did you break the tab between the two switches in the duplex switch? also have you checked the meter on other circuits to be sure it is accurate. Also if it is digital have you changed the battery.
 
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Old 03-01-13, 10:08 AM
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Ticket Closed

I guess I can say "ticket closed". Got it working. Thanks for the help.

Yeah, there was a tab I wasn't aware of on duplex switch. I removed it and now all is working correctly. It's funny but I purposely looked for a tab before I initially installed switch but I looked at the other side, didn't see one and thought, why would there be a tab connecting the switches anyway?

So it appears the original wiring, outlets were on one leg of service and lights on the other and with the tab in place, allowed the 240V to happen, which led me to thinking there was "something wrong or broken" with switch.

I actually did more than break out the tab. I had done the project with a length of #10 romex I had laying around and was it ever a bear to work with attaching to screws and pushing switch and outlet into boxes. I re-wired with #12 which was so much easier. The existing wiring in the house in most places is #10.

Also thanks for reviewing my diagram. I feel much more at ease now that it's working properly and knowing it's done correctly. Thanks again.
 
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Old 03-01-13, 10:25 AM
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The existing wiring in the house in most places is #10.
Is it aluminum? If so we may have an other problem. Aluminum can't be directly connected to copper even with antioxidant paste.
 
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Old 03-01-13, 10:41 AM
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All wiring in house is copper.
 
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