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

 

[D Skelton]

but if i'd put the brackets in properly....

SQRT ( I²A + I²B + I²C - (IA x IB) - (IB x IC) - (IC x IA)) it would be the same. n'est pas?

Yes indeedy

 

[D Skelton]

Who cares what the formular is? the neutral Conductor does not need to be three times bigger than the phase conductor LOL

Agreed entirely.

Biff hit the nail on the head. Epic fail of a thread!

 

[44ALLAN]

mmmm - Bishop's Finger....

...nice, but what a whammer headache in the morning lol

Bitter and Twisted

 

[Engineer54]

Just makes me wonder what the hell is being taught these day's at colleges?? Seems not much in the way of 3 phase distribution and theory!!

Pretty sad state of affairs when you think about it!!

 

[Darkwood]

The OP has asked a good question that often confuses alot of the newby sparkies out there for a very good reason that it relies on maths and angle of phase.. now seen as we are bottom of the world league in education for Maths, Science and English its no surprise we are seeing this kind of misunderstanding and not the fault of those asking the question but the system under which they were taught...

What does really surprise me is many regular established members not understanding the theory here.... if you have doubt and think i may be pointing the finger at you then your doubt is most likely correct .... as many members have pointed out a common N of a 3ph supply only has to be sized to the max load of 1ph (excluding Harmonics to simplify the point) the more the phases are in load unity the less current will flow in the common N.