3 phase 63A

[dave-gardiner]

Hi
we have a 3 phase 63A isolator.
i have been asked to supply from this 3 x single phase 63A sockets. I have said this cannot be done because the neutral is only sized for the 63A supply. But now i am questioning myself. Help please

 

[Plonker 3]

How do you think the neutral would cope of a 3 phase machine was connected to the isolator?

 

[guest119]

How do you think the neutral would cope of a 3 phase machine was connected to the isolator?

How is that relevant to the question?

Boydy

 

[dave-gardiner]

Need help not more questions. Ha ha

 

[Plonker 3]

Because the neutral would still be the same size, yet potentially could be carrying 63 amps from each phase!!!!

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The answer is yes you can do it, but ensure each single phase socket is fused individually.

 

[dave-gardiner]

Cannot guarantee a balanced load

 

[Plonker 3]

But neither can a 3 phase DB

 

[spark 68]

Or a sub-main, I feel a sense of deja vu, lol

 

[MDJ]

Hi
. But now i am questioning myself. Help please

Why? what suddenly made you stop and question yourself?

 

[Guest 004]

sorry must disagree, as the op states he wants 3 x 63A Single phase supplies. Fully loaded you can have a current of 180 Amps flowing down the neutral. 3 phase machines are different, because any unbalanced currents just flow down the neutral.

 

[Plonker 3]

sorry must disagree, as the op states he wants 3 x 63A Single phase supplies. Fully loaded you can have a current of 180 Amps flowing down the neutral. 3 phase machines are different, because any unbalanced currents just flow down the neutral.

What!!!!!!

Do you over sizer all your neutrals on sub mains to compensate for that?

 

[MDJ]

sorry must disagree, as the op states he wants 3 x 63A Single phase supplies. Fully loaded you can have a current of 180 Amps flowing down the neutral. 3 phase machines are different, because any unbalanced currents just flow down the neutral.

What if you had a 3 phase 63 amp Distribution board with every circuit in it single phase and it was full to capacity?

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What!!!!!!

Do you over sizer all your neutrals on sub mains to compensate for that?

Yeah why not :sifone:

 

[Silly Sausage]

sorry must disagree, as the op states he wants 3 x 63A Single phase supplies. Fully loaded you can have a current of 180 Amps flowing down the neutral. 3 phase machines are different, because any unbalanced currents just flow down the neutral.

Hahaha....GOOD thinking Sir!!!

 

[spark 68]

sorry must disagree, as the op states he wants 3 x 63A Single phase supplies. Fully loaded you can have a current of 180 Amps flowing down the neutral. 3 phase machines are different, because any unbalanced currents just flow down the neutral.

Yes that is the worst case scenario, if only two phases were fully loaded simultaneously, and it is actually 1.73 X, every other combination would cancel out to a degree.

 

[dave-gardiner]

So 3 x 63A single phase sockets taking full load with neutral potential 189A is ok?