Maximum load in a 100 amp box???

Old 11-30-09, 11:08 AM
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Maximum load in a 100 amp box???

I have a 100 amp load center that has all the slots filled. My question is can I use mini breakers and what is the total number of amps allowed? I have read that you can not exceed the 100, but that sounds incorrect because they sell the boxes with more than 100 amps total.
Old 11-30-09, 11:24 AM
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What is the make and model number of your box? It should be printed on the panel label. This will determine if mini (skinny, tandem) breakers are allowed in that panel.

The total amps of the breaker handles added up does not matter.
Old 11-30-09, 03:05 PM
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The amperage is the maximum you can use at any one time.

Your main panel may be 100 amps, and everything in the house totals up to 200 amps, but you may only be using 50 amps at any one time!

For example you may have an electric heater which is 20 amps and a window air conditioner which is 20 amps. Do you have both of these turned on at the same time? No.

Also these may actually only use about 11 amps each even though they are on 20 amp breakers.

Pretty much the same throughout the house. You may have a 20 amp breaker for a bedroom, but might only use one light and only at night. And that might be using only 1 amp!

So don't count the amperage on the breakers, rather count only what you have turned on all at the same time. (For if you are exceeding the capacity of the main panel breaker.)

And if your main breaker never trips, you could assume you are not using more than 100 amps at any one time.

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