Electrical Wiring in the Home/Low voltage on circuit


This circuit involved One bathroom light above the sink, one  receptacle at the sink (it is not GFI) And one Light above a built in vanity.
Both the receptacle and light at the bathroom sink are wired into a wall switch.   
When the switch is in the "on" position, both the light and the receptacle read 102V between neutral and hot wires. The reading between hot wire and ground is 120V at the receptacle. The reading between the hot wire and the neutral bar in the breaker box is 120V. The light over the vanity is on another switch that is wired off the switch for the bath light and receptacle. However, the reading on the light bar is 120v. Does this mean that the wire running from the switch to the bath receptacle is bad...since the light bar over the vanity is at 120v and is wired to the same receptacle?


When you get readings like that, it means that some things are in series with each other.  There are two causes. 1) It was wired incorrectly. or 2)There is a wire loose, usually a white neutral. (if you get 120 between ground and hot, and less between neutral and hot, it is definitely a neutral wire)

If you recently added something, then it was probably wired wrong.  Many people make the mistake of trying to tap off of a switch.  If there are only 2 wires in one cable at the switch, you can't tap off of that.

If the things have been there and worked, then a wire has come loose.  Most likely it is either in a wire nut, or at an outlet where the wires are pushed into the back rather than connected to the side screws. To make matters worse, it could be at a device is working, since it could be the wire leaving the device that is bad.  So check everything on the circuit. Move the wires to the screws of the outlets, if they are in the back. Remove the wire nuts and make sure all of the metal parts of the wire are touching.

You should replace the outlet with a GFCI for safety.
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Electrical Wiring in the Home

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Bob Sponaugle


Just about any home wiring question. (not appliance repair) I have done all kinds of home wiring for myself, including adding a new breaker box, etc. Please, questions from North America only. Please be specific with details.

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