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Took me 'till I was installing the

2012-01-09 01:56:11.040037+00 by Dan Lyke 11 comments

Took me 'till I was installing the breakers in the box to realize that single pole GFCI and Edison circuits were incompatible. Duh. Sigh.

comments in ascending chronological order (reverse):

#Comment Re: made: 2012-01-09 09:28:12.665199+00 by: andylyke

Oops! But you can use the receptacle style GFCI, as long as you don't daisy chain them. This only means that you have to buy more GFCI units.

#Comment Re: made: 2012-01-09 15:16:25.803632+00 by: Dan Lyke

The Eaton/Cutler-Hammer literature suggests I can use the double-pole GFCI breakers, which also solves the problem of making sure that all circuits in the box are off when the breaker is thrown. It also kills the other circuit in the box, but: oh well.

#Comment Re: made: 2012-01-09 18:32:05.160198+00 by: TheSHAD0W

I'd strongly recommend using GFCI outlets rather than breakers; they're much less expensive.

#Comment Re: made: 2012-01-09 18:43:49.079625+00 by: andylyke [edit history]

I agree with TheSHADOW in a way - although the receptacle GFCIs may, in the aggregate, be more expensive (you can't daisy chain them in shared neutral circuits, so a run of 5 outlet straps would have 5 GFCIs as opposed to one panel mounted GFCI for the chain), If you have a failure, the individual receptacle GFCI is far less expensive to replace, and you do know conclusively whether it's a device failure or a ground fault.

#Comment Re: made: 2012-01-09 19:55:17.088284+00 by: Mars Saxman

What is an "edison circuit"? Never heard that term before.

#Comment Re: made: 2012-01-09 20:34:04.030893+00 by: Mars Saxman

oh, i see, split neutral.

#Comment Re: made: 2012-01-09 20:34:15.321839+00 by: andylyke

@Mars: I take it to be a shared neutral configuration on a 120/240 3 wire circuit where some receptacles are connected to the A leg, and others to the B leg, but all share the neutral, so the neutral current will be the difference between the loads on the respective A and B legs. I hadn't heard the term before, and particularly since Edison was the DC proponent, and Westinghouse the AC proponent, it seems puzzling.

#Comment Re: made: 2012-01-09 20:38:53.736879+00 by: andylyke

Okay - Edison used the shared neutral on DC circuits.

#Comment Re: made: 2012-01-10 02:29:23.514704+00 by: meuon

As long as A and B are similar loads, sharing a neutral works. Normal residential usage is OK. If I were going to be running inductive motors with varying loads, I'd run hot and neutral as far home (to the panel) as I could. I've got two GFCI breakers in my box, one feeding the hot tub (two phases, 30amp) and one feeding the kitchen (two phases, 20amp) and a GFCI outlet in the bathroom... which I think is currently unpowered.

#Comment Re: made: 2012-01-10 14:01:38.981437+00 by: TheSHAD0W

So long as the shared neutral conductor is the same size as the hot lines, having differing loads on the two hot sides doesn't matter.

#Comment Re: made: 2012-01-10 17:27:06.757176+00 by: Larry Burton

Functionally, sharing a neutral works but it can really cause some problems with lockout procedures.