How do I test to see if a 220 line is energized? Breakers are not clearly marked at the box and I need to be assured of a disconnect before I work on the stove outlet. The wiring is 20-year-old service with two blacks and a ground ending in a outlet that accepts a 3-prong male from the stove. Will a simple outlet tester do the job? Please be specific about the procedure. MK
According to mike korenchuk :
They don't make outlet testers for those outlets.
Important: 220V circuits have _two_ breakers. The breakers _should_ be tied together, but they may not be in older installations.
What you want is a means to test whether there's voltage between either of the two blacks and the ground wire.
At first glance, using a voltmeter or neon tester first between one black and the ground prong, and then between the other black and the ground prong seems adequate. Once both tests yield "no voltage", you're good. If one goes "no voltage", and the other doesn't, at least you've found one of the two breakers.
It really isn't, because voltmeters and neon testers draw so little current that induced voltage beween one energized hot wire and an adjacent non-energized hot wire will show power in both leads. Theoretically, if you got _both_ of them de-energized, the voltmeter or neon should show non-energized both ways.
So, if you used a neon tester and got "dead" both ways, you're okay.
Do, of course, test both ways _before_ turning off breakers to make sure that the tester is working, etc.
If you do all of the testing and you cannot get both tests to show "dead", then you're going to need to replace the neon or voltmeter tester with a "real" load to eliminate induction effects. A 7w bulb (christmas light or nightlight) on short wire probes (be _careful_) will do the job.
i used to test them, a/c 220 outlets to make sure both legs of the circuit was working.. this is what i used.. a 220 volt light bulb in a socket with pig tails on it... checked one hot and ground and the light would light up half way bright--- then checked the other hot side to ground and it would light up half way(as its 120 volts) the checked out both hots with one pigtail to each.. then i would get full brightness with 220 volt bulb... this way i knew the 220 a/c line was working... you can do the same thing with a multi meter.. just check each leg to see if you got 120 volts to each and then go to the two hots and look for 220 volts from it.....
I would revise that to...check between either black and a KNOWN, GOOD ground.
Wishing you and yours a happy Thanksgiving season...
Trent
According to Trent© :
... to take account of the (hopefully unlikely) possibility that the ground is defective.
According to Tony Hwang :
I wouldn't trust a multi-meter for this. Especially the high impedance ones. You could reasonably trust it to be right if there's "no voltage", but not otherwise.
Don't know what you mean by a simple outlet tester, but if you mean a bulb in a socket with two probes the answer is yes. A three prong outlet means two hot legs and a ground. Voltage between the two legs is 240 and voltage between the either leg and the ground is 120. Put a small bulb, e.g.,
40W in your tester and test any two of the outlet slots. You have 3 possibilities a-b, a-c, and b-c. Two possibilities will be 120 volt and on possibility will be 220. Not that you care but you can tell by how bright the bulb is and if you hold the probes in contact for more than a second the on the two hot legs the bulb may burn out.But if you have an outlet and plug, why do you need to make sure the power is off? Just unplug the stove to work on it.
mike korenchuk wrote:
for a floor tile project.
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