3-wire feeders

Old 10-02-04, 06:06 PM
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3-wire feeders

I have a question. I have been doing electrical work for several years now and was explaining to an apprentice how 3-wire feeders work, and that you have to have the hots on different phases in the panel. Well i was wondering if you were pulling the exact same load on each phase, in theory there is no load on the nuetral right?. So if you loosened the nuetral in the panel would you get some arcing?. Thanks from the knowledge!!!
Old 10-02-04, 06:23 PM
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If the load is exactly the same on each of the hot wires, then the neutral is carrying no load and is completely superfluous. You could disconnect it with no ill effect. And of course there would be no arcing when you loosened it, since there is no current flowing on it.

The paragraph above is just theoretical of course. It isn't practical to disconnect the neutral because the loads are rarely perfectly balanced. If you have loosened or disconnected the neutral, and the load becomes unbalanced, then you've got trouble. The voltage drop across some loads would rise above 120 and the voltage drop across other loads would fall below 120. The difference might be dramatic, and serious damage and hazardous conditions would occur.

These hazards, of course, are why the code imposes additional conditions on the neutral connections on a multiwire circuit.
Old 10-03-04, 04:48 AM
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I agree with John. Also consider, if the neutral was lifted, the voltage accross a single 120V rated device, may be as high as 240V.

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