I don't know

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Well, if you are trying to wire a fixture and you are trying to determine which is hot: get a simple circuit tester (usually an led attached to two probes), touch one probe to the jbox and touch the other probe to each wire in turn. The hot wire will light the circuit tester when it makes contact. mark the hot wire by adding black tape to the insulation.
 
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Well if they are power to a light the switch is on, one will be hot and one not. If the switch is off both won’t have power. That’s when the power comes to the switch first like this one. The box looks like its plastic so you won’t see a good ground there with a tester that has two probes.

You could take a knife and scrape some of the paint off and see what color is below.
 
You guys are awesome! I built a tester with a led, then also scraped a bunch of crap off of the wire jackets. Works great now

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You need a known good ground to check which wire is hot. Use one conductor of an extension cord and clip leads as a test lead to a water pipe or BX shield or load center cover.

BTW, with the LED tester drawing so little current, a 'good ground' might be a screwdriver shaft stuck in the earth or water flowing out of a faucet.
 
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:rofl: :rofl:

I thought of giving you a homework assignment involving calculating the current draw of LED testers but I think this assignment will do you much more benefit.

Using this search
http://www.google.com/search?client...+denial+"defense+mechanism"&ie=UTF-8&oe=UTF-8
figure out the connections between my post and your conduct.

It's an open-book test and you can ask others if you need.

Post back if you want a grade on your comprehension of this concept.
 
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You do realize that your wires could be backwards and the light will still work ?
For a safe installation, you need to know which one is hot.
 
I think the OK was for the use of water for ground, water has questionable coductivity and with pipes made out of plastic. You will just get a false reading.
 
I'm taking the weekend off and I'll forward my calls to Mr. Peedy. :D
 
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