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Silly question, but how much can a 63amp breaker pull?

Darkslcie · 2022-02-13 11:55:29

I know I know, it should be obvious. No more than 15.2kw. ( breaker is a 63amp c120n B63-18340) But the breaker is B rated, so allows surges of 3 to 5 times that. So can anyone explain to me why I was able to pull 18.9kw when doing a stress test? (And not trip the breaker, had it at that for a minute or two

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13-02-2022 12:55pm

#1

Darkslcie

Registered Users Posts: 114 ✭✭

Join Date: August 2007

Posts: 92

I know I know, it should be obvious. No more than 15.2kw. ( breaker is a 63amp c120n B63-18340)

But the breaker is B rated, so allows surges of 3 to 5 times that.

So can anyone explain to me why I was able to pull 18.9kw when doing a stress test? (And not trip the breaker, had it at that for a minute or two

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#2 13-02-2022 12:57pm
Darkslcie

Registered Users Posts: 114 ✭✭

Join Date: August 2007

Posts: 92

Hmmm I wonder if the the 4kw to charge the solar battery via the inverter is bypassing the breaker as it's on its own breaker.... ?

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#3 13-02-2022 1:24pm
10-10-20

Registered Users Posts: 7,169 ✭✭✭

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Posts: 6992

Look at the graphs for B class.
https://www.electricalclassroom.com/b-c-d-k-and-z-mcb-trip-curves/#1-class-b-trip-curve
They won't trip instantaneously on a sustained overload, they need time or a higher pull current.

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