Bain Posted May 30, 2009 Report Posted May 30, 2009 I'm in the middle of a little, uh, spat with a builder who pulled a 100-amp sub-panel off a 200-amp main panel in new construction. I was always told that the sub shouldn't exceed 30% of the capacity of the main. Nevermind that the service should have been appropriately sized in the first place, obviating the need for the sub-panel. Is the 30% rule a common sense thing, or is it supported by the NEC?
Neal Lewis Posted May 30, 2009 Report Posted May 30, 2009 Never heard of the 30% rule, and I don't think it's in the NEC. I see that same situation quite often. Why do you say the service isn't large enough just because of the need for a subpanel?
Jim Katen Posted May 30, 2009 Report Posted May 30, 2009 I'm in the middle of a little, uh, spat with a builder who pulled a 100-amp sub-panel off a 200-amp main panel in new construction. I was always told that the sub shouldn't exceed 30% of the capacity of the main. Nevermind that the service should have been appropriately sized in the first place, obviating the need for the sub-panel. Is the 30% rule a common sense thing, or is it supported by the NEC? I've never heard of such a rule. It certainly isn't in the NEC. Where did you hear it? - Jim Katen, Oregon
Bain Posted May 30, 2009 Author Report Posted May 30, 2009 I honestly don't recall. I assume I heard it from an electrician back when I was a builder . . .
Billy_Bob Posted May 30, 2009 Report Posted May 30, 2009 I've seen plenty of 200 amp main panels outside feeding 200 amp subpanels inside. Quite common.
msteger Posted May 30, 2009 Report Posted May 30, 2009 I've never heard of that rule, either. When I subpanels off 200 Amp mains, the subpanels are normally either 100 Amp or 60 Amp rated.
Bain Posted May 30, 2009 Author Report Posted May 30, 2009 Mmmm, so it appears I've been operating on faulty information. Thanks for setting me straight.
Chad Fabry Posted May 31, 2009 Report Posted May 31, 2009 Mmmm, so it appears I've been operating on faulty information. I hate when that happens to me. Mmmm, so it appears I've been operating on faulty information. Thanks for setting me straight. Being set straight is gratifying but it doesn't completely ease the pain of being wrong in the first place..
Bain Posted May 31, 2009 Author Report Posted May 31, 2009 Mmmm, so it appears I've been operating on faulty information. I hate when that happens to me. Mmmm, so it appears I've been operating on faulty information. Thanks for setting me straight. Being set straight is gratifying but it doesn't completely ease the pain of being wrong in the first place.. Yeah, but at least I'm showing progress. Twenty years ago, you could have tied me to a tree, soaked me with gasoline, and held a Bic a few inches from my nose . . . I still wouldn't have admitted I was wrong.
hausdok Posted May 31, 2009 Report Posted May 31, 2009 Yeah, but at least I'm showing progress. Twenty years ago, you could have tied me to a tree, soaked me with gasoline, and held a Bic a few inches from my nose . . . I still wouldn't have admitted I was wrong. In the modern home inspector vernacular, that's known as being somewhat peckish. [:-graduat ONE TEAM - ONE FIGHT!!! Mike
John Dirks Jr Posted May 31, 2009 Report Posted May 31, 2009 I get to learn from others being wrong so hey ya'll, keep stickin your neck out would ya. Thanks....[:-graduat
Bob White Posted May 31, 2009 Report Posted May 31, 2009 Yeah, but at least I'm showing progress. Twenty years ago, you could have tied me to a tree, soaked me with gasoline, and held a Bic a few inches from my nose . . . I still wouldn't have admitted I was wrong. In the modern home inspector vernacular, that's known as being somewhat peckish. [:-graduat ONE TEAM - ONE FIGHT!!! Mike I don't care who you are --- that's funny.
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