Brain fart, 3phase

[Dylboy]

Hello all!

Hope its a good Tuesday.

I am having a bit of a brain fart and I guess a bit sleep deprived from the little one.

But below image i have drawn is a 3phase supply then supplying 3 x single phase main switches, your typical 3 phase house...

Now my brain is not working on:

- can each phase pull lets say 60Amps each and not trip the CB as it is rated at 80Amps
Or will the combined amps which is over 80A trip the CB. ?

Essentially is the 3phase CB like 3 single pole breakers joined, so each "single pole" has the trip at 80Amps thus allowing each of the phases to pull a max of 80Amps? And if one of them trips it then trips the whole CB ?

Apologies if this is basic but I am having a struggle today.



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[Leecatt]

The three phase breaker is actually three separate breakers joined together mechanically. Unless it has only one handle then it is constructed differently but works the same.

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[Lourens.dL]

Just to add, each of the three beakers is rated at 80A and if one phase overload then all will trip.

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[Dylboy]

Ahhh ok brilliant, I thought as much, thanks gents, really appreciate it !

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[Justloadit]

Just to add, each of the three beakers is rated at 80A and if one phase overload then all will trip.

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You would not have it any other way, switching one phase off on a 3 phase load is detrimental to the equipment, unless it is a heater bank