To be absolutely correct the white wire in this situation should be the wire that is always hot and the black wire goes to the light and is made hot when the light is turned on using the switch you are installing this very moment but once in awhile you find the wires reversed. I have an old 2 way 1 gang light switch to replace but the one currently fitted has 2 red wires 1 black wire as opposed to the three different wires as shown on most sites that i checked out.
Adding A Receptacle
Light switch with only one black wire. You have to have a common and i did was run a single wire from a box that uses a common wire. Ive decided to put this faq together to help those with questions about installing ge 3 way switches. Run white wemo to this common wire you add. The hot wire from the breaker usually black neutral. After some help if possible. The hot wire in a 120 volt residential ac circuit usually is coated with black insulation while the return or neutral wire is white.
Run 2nd wemo black wire to black wire from old switch. One is the power coming into the box the other black is power going to the light. My apologies if this has been tackled before but im trying to replace an old light switch in my bathroom and the old one only had two black wires connected to it. I have 4 installed like this. Connect the black wire to the other brass screw. My old light switch in my bathroom only has two black wires connected to it.
Wiring a three way switch. So usually a standard single pole dumb switch has two blacks. With only 1 black and 1 white they are both black as far as hooking up wemo. I would check that the load wire probably black is securely connected to the screw labeled load. If you have a ground wire connect the ground wire to the green screw. For the ground on the wemo just cap.
The return wire for circuits usually white load. Thinking about it it may have been 2 blacks and 1 red but either way there are only the two colours. When there is just one white wire and just one black wire altogether both are to be treated as hot. In existing 3 way wiring this wire toggles hot between two. Wemo black wire to the white wire from old switch. This is a typical wiring setup for a 3 way light switch with black white red and ground wires.
A single pole single throw switch such as a light switch. Smart switches use a neutral and a ground wire in addition to the line and load black wires. The wire that will be hot when the circuit is completed to your light usually black traveler. If you dont have a ground wire leave the green screw unconnected.