Load center terminology confusion


Old 09-02-16, 07:51 AM
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Load center terminology confusion

Can someone explain what 40 circuit 30 space or 40 circuit 20 space means?
Never mind, I found my answer.
For others wondering:
in the case of 40 circuit - 30 space, you have a total of 30 breaker slots. 10 of those slots are able to accept tandem breakers. or in the 40 circuit - 20 space, all 20 slots can accept tandem breakers.

Tandem breaker picture[ATTACH=CONFIG]70379[/ATTACH]
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Last edited by Jon Mullins; 09-02-16 at 08:11 AM.
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Old 09-02-16, 08:10 AM
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40-30 means 30 full size breakers for 30 circuits or 20 full size breakers and 10 tandem breakers for 40 circuits. Usually only 10 spaces are designated for tandems. Tandems aren't allowed and/or won't fit in the other spaces.

40-20 means you can have 20 full size breakers (20 circuits) or up to 20 tandem breakers for a total of 40 circuits.

Some panels also take quads but the explanation is similar. Quads allow for a pair of single pole breakers and a two pole breaker in the same device or four single pole..
Old 09-02-16, 08:13 AM
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Thanks for the answer ray2047

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