Just replaced a bathroom light and now it won't turn off. Comeing from the wall were the old light was is 2 white/ 2 black/ and 2 green wires. Can someone please help me figure this very frustating matter.

Usually white is "neutral" (the return leg for the voltage), black is the "line" (main voltage), and green is "ground".

1. Did you try to replace the switch with an identically functioning one?
2. Does only one switch control the light, or are there two (or more)?
3. How many terminals on the old switch? How many on the new switch? Is there a ground screw on both the old switch and the new switch?
4. Did you or someone else disconnect the white wires in the box?
5. Are the white, black and green wires coming from two, separate cables (look in the box for the outer cover)?

Re-reading your question, I think you're saying that in the box on the wall, where the light is, there are two greens, two blacks, and two whites. Correct? One black is "live". You can use a tester light or a voltmeter to determine which one. I'll bet that a white and black pair go to a switch. You should use a continuity tester to determine which pair. The white coming in with the "live" wire should be tied to the light (light-colored terminal if the screws are different colors). The "live" black wire connects to the white that goes to a switch. The black wire comes back from the switch. The white wire coming from the switch should be connected to the other terminal of the light (darker-colored terminal).

The greens should be tied together and a pigtail should be run from the two greens to the light's ground screw or ground wire.

I bet you unwired all the splices in the box and didn't label anything... right?

Perito has got it with this. It's called a witch loop:

Quote:

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Originally Posted by Perito

Re-reading your question, I think you're saying that in the box on the wall, where the light is, there are two greens, two blacks, and two whites. Correct? One black is "live". You can use a tester light or a voltmeter to determine which one. I'll bet that a white and black pair go to a switch. You should use a continuity tester to determine which pair. The white coming in with the "live" wire should be tied to the light (light-colored terminal if the screws are different colors). The "live" black wire connects to the other black wire and that goes to a switch. The white wire comes from the switch and should be labeled with a piece of electrical tape around its end (if it's not, you do it). That's to differentiate it from a neutral. The white wire coming from the switch should be connected to the other terminal of the light (darker-colored terminal).

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The only thing wrong is the bold part. The white must carry the power to the switch and the black is the switch leg back up to the light.

Quote:

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Originally Posted by stanfortyman

The white must carry the power to the switch and the black is the switch leg back up to the light.

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Thanks for that. I appreciate it. I corrected my post.

1. Turn the circuit breaker off. Wire the light fixture into ONE set of black and white wires.
2. Separate the other set of wires, and cap them off with wire nuts.
3. Turn the breaker on. If the light comes on, you have it connected to the power from the breaker box. The other two wires are the "switch loop."
(Repeat steps one and two until you find the two wires from the breaker box.)

Once you have determined the power wires, turn the breaker off and proceed as follows:

1. Wrap a piece of electrical tape around the white Switch Loop wire.
2. Connect the white switch loop wire to the black power wire.
3. Connect the black switch loop wire to the "hot" side of the light fixture. (Either a black wire, or a brass colored screw)
Connect the white power wire to the neutral side of the fixture (White wire, or silver colored screw)

Remember the next time you replace a device, you probably don't have to take apart all the wires in the box, just disconnect the ones going to the ting you are replacing!

If you do have to take something completely apart, make a diagram of how it is hooked up BEFORE you start.