Basic electric service panel questions

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JMingrone

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I'm having a home inspection this weekend on the house I'm selling and I'm a little concerned about the electrical inspection.

A couple quick questions:
1) For a 200 amp service, you draw 200 amps from each leg, right?
2) Is it a problem (does code require) that the breakers on each leg total to less than 200? Or is it only necessary that the actual load being drawn be less than 200 amps? I have a total of 230 amps of breakers on one leg and 200 on the other.

Will this be a problem?

Thanks
 

Murphy625

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Yes.. 200 max on each leg.
No. Breakers can total far more than the mains. The mains are protected by their own breaker. It is assumed that you will never draw the maximum current on every breaker simultaneously. If you did, the main breaker on a mains panel, or the feeder circuit breaker on a main lug panel would trip.

Always remember, breakers are not there to protect the devices. Breakers are only meant to protect the wires.

Hope that helps,
 

Jadnashua

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It might be an issue if the panel was full of breakers and you had lots of heavy use appliances in the home, other than that, not a problem. For example, say you had multiple, big water heaters, big a/c units, a pool heater, a commercial style 8-pot stove and multiple ovens...then 200A may not be adequate. This isn't an issue for the vast majority of people...
 

hj

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It could also be a problem if you had ALL the high draw 120v items, such as microwave, space heaters, blow dryers, etc., all on the same leg of the feed and they all operated simultaneously at the same time as the major 240v ones, such as A/C units, water heaters, pump, and oven, which although unlikely could happen at some time.
 
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DonL

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It could also be a problem if you had ALL the high draw 120v items, such as microwave, space heaters, blow dryers, etc., all on the same leg of the feed and they all operated simultaneously at the same time as the major 240v ones, such as A/C units, water heaters, pump, and oven, which although unlikely could happen at some time.


That is Exactly how a lot of Inspectors Test here, when you are buying a house.

But they are the Good ones, and you pay well for a good inspection.


Good Luck.
 

Murphy625

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It could also be a problem if you had ALL the high draw 120v items, such as microwave, space heaters, blow dryers, etc., all on the same leg of the feed and they all operated simultaneously at the same time as the major 240v ones, such as A/C units, water heaters, pump, and oven, which although unlikely could happen at some time.

Ok.. I'll bite..
The way I'm reading your reply, it seems that you're implying that drawing too many amps on one leg is somehow more detrimental than drawing too many amps equally on both legs.

What difference does it make?

And for the sake of this discussion, lets leave out the theoretical voltage drop issues.
 

ActionDave

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There is no way to draw 200A on one leg of a house unless it was your sole mission in life.
 

Leejosepho

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It could also be a problem if you had ALL the high draw 120v items, such as microwave, space heaters, blow dryers, etc., all on the same leg of the feed and they all operated simultaneously at the same time as the major 240v ones, such as A/C units, water heaters, pump, and oven, which although unlikely could happen at some time.
Ok.. I'll bite..
The way I'm reading your reply, it seems that you're implying that drawing too many amps on one leg is somehow more detrimental than drawing too many amps equally on both legs.
No, I think his point is simply that an overload could happen more easily and trip a main breaker "if you had ALL the high draw 120v items, such as microwave, space heaters, blow dryers, etc., all on the same leg of the feed and they all operated simultaneously at the same time as the major 240v ones, such as A/C units, water heaters, pump, and oven". Balanced loads seem better overall.
 
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hj

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An overload on EITHER leg will trip the main breaker, but it would be more difficult to overload both of them at the same time, unless the service were seriously undersized, (I have seen houses with 400 amp systems). The ideal is to have the two legs so well balanced that you would not need the neutral, but that would only happen in a Utopian system.
 

Speedy Petey

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There is no way to draw 200A on one leg of a house unless it was your sole mission in life.
Completely agree.
It is also nearly impossible to balance the load in a residential application. The loads are so transient that it's not worth trying.
Just fill the panel with circuits and you'll be as balanced as you could ever be.
 

ActionDave

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Completely agree.
It is also nearly impossible to balance the load in a residential application. The loads are so transient that it's not worth trying.
Just fill the panel with circuits and you'll be as balanced as you could ever be.
Completely agree with you on this point. Time for a man hug?
 
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DonL

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I don't think Load Balancing is a big problem in a home, if it is wired correctly.

I have seen 3 phase systems that required it, or it would trip a ground fault.


Be careful playing with electricity, and have fun doing it.
 
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