I am changing an outside light with a inside wall switch there is 2 cables going to the outside box. ( 3 wires -white w/red line wire and black wire and green ground wire ) other cable 3 wires is white wire and black wire and green ground wire.On the inside switch is 3 wires white wire a black wire a green ground wire.for some reason it is not working, can any one tell me how to wire and or test for power. thank you
Sounds like, cable #1 is coming from the Service Panel. The white ( with red line?) is the Neutral and connects to the white wire coming from the light fixture. The black is the Hot and connects to the black of the other cable set. The grounds all connect together and a pig tail should be fastened to the box if it is metal. The white wire from the other cable set should have black tape wrapped around the end to re-identify it as Hot and it should connect to the black wire coming from the light fixture. At the switch, connect the black to one terminal and wrap black tape on the white wire end and connect it to the other terminal. The ground should connect to the green ground terminal and if it has a metal box,pig tail to that.
In a normal 120V system you will have Black(hot) White( neutral) Green or bare copper(ground). So the green wire are wired together with a pig tail to the ground on the switch (if grounded) the white wire, if neutral, should be wired together also and no connection to the switch. The black wire should be wired to the switch and the other black wire to the other side or pole of the switch. But I think you are wiring to an existing switch, meaning it controls another light already. In that case the three wires will be White(hot) Black(to the existing light) green or bare copper (ground). To find out check the switch wires white to ground If you get 120V on the white that means you do not have a neutral at the switch, or what is commonly called light wiring. With out a neutral the out side light will not work. So you have to pull wire to the switch to get a neutral. Good Luck.
Assuming the inside wire is proper - separate the wires at the outside box (so they cannot touch anything - turn on the switch - touch one lead of a circuit tester to the black wire outside the other to the ground (should light) - try again to the white wire (again - should light) If neither works the switch or the wire is bad.
I changed my outside light and sounds like the wires were similar to yours. Make sure you have the power turned off. And, connect and twist the wires (same colored) together, and use the caps, and connect the green ground wire and turn on the power to test it again. Might want someone near the power switch and someone to watch the light to make sure sparks don't fly. And, make sure you have a bulb that works in there. Otherwise might want to contact someone knowledgeable (family member/electrician) with help.
IF switch and bulb are good, have you tested the light socket? Black is the HOT lead. Power (hot) goes from box, to switch, to light, to neutral (power.) THIS puts the switch in the HOT lead. Green (ground) connects to ALL points.
