multi-wire circuit question

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  #1  
Old 09-25-06, 11:09 AM
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multi-wire circuit question

Quick question. I have a multi-wire circuit, 20A breakers on different phases, one hot feeding the refrigerator, one feeding a kitchen countertop receptacle. They are spliced from a 12/3 whip to two 12/2 branches in the attic.

I need to swap out the receptacle on the refrigerator circuit. If I turn off the breaker for the fridge, obviously the hot will not be energized. But because the neutral is shared, would the neutral be energized? My thinking is no, because no current is flowing thru the receptacle to be returned to the panel.

I could turn off the other circuit, but Iím curious as to why or why not the line would be energized. Obviously if the hots were on the same yolk they would definitely need to be off, but if that were the case they would be on a double pole breaker.

Thanks all.
 
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Old 09-25-06, 11:19 AM
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The neutral will be "energized". It is unlikely that you will get railed by working on it, it can happen.

If, say for example, there were a connection between where the circuits become common and the panel, the current would go through you and the ground wire back to the source.
 
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Old 09-25-06, 11:22 AM
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That was my thinking also. That is would be energized because itís connected to a neutral that has current flowing thru it.

Iíll turn off both breakers. Thanks jwhite !
 
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Old 09-25-06, 11:30 AM
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This is why I only put multi-wire circuits on 240 amp breakers (or 120 volt breakers with handle ties).
 
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Old 09-25-06, 11:38 AM
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While it is less likely to happen on 120/240 volt, I have gotten railed bad on 277/480 volt under these exact same conditions.
 
  #6  
Old 09-25-06, 01:54 PM
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Unfortunately this was the only way to do it. Space limitations and access forced me to put every new circuit on a shared neutral. The breakers are twins, so the hots that share a neutral are not directly above/below each other.

The wires are all numbered, so I plan to create a list of the hots and the shared neutrals, and affix it to the panel door, so I, and the next owner, will know which circuits go with which neutral.
 
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Old 09-25-06, 07:44 PM
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Talking

Turn on the blender, then grab the neutral.
IMO, Disconnect both ckts.
 
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Old 09-25-06, 08:17 PM
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absolutely. Thanks lee.
 
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