Cable size for a 3ph 15kw oven

[pkonrad]

Hi guys

Have to install a 3ph 15kw oven. I know to calculate the amps for single phase u divide 150000 by 230 which gives you around 63 amps but how do u calculate it for three phase, simply use 400? And then what size of cable will I need. for 63 amps I know it will b 16 but need to know the difference for three phase. Thanks for any replys

 

[ProDave]

Well it's simple really.

15KW / 400V / (the square root of 3) which gives 21.7A

The alternative "intuitive" method is that the cooker is a total load of 15Kw, so you can think of that as 5KW fed from each phase, which at 230V is surprise surprise the same 21.7A

So depending upon how the cable is erected, you might get away with 2.5mm, but 4mm or even 6mm would be better.

 

[Adrian41uk]

:SaluteThe easy way is to think of this as split evenly across the three phases, so 15/3 = 5kW. 5kW @ 230V ~ 22A.

The full calculation is 15000 / (sqrt(3) * 400) = 21.74A per phase.

You'll need to know about the cable routing before you decide on its size. It might be 2.5mm or it may need to be 4.0mm or bigger.....

 

[batty]

He's fast rename him fast Dave

 

[Graham Lister]

Would go for 6mm depending on length or run, have seen many wired in 10mm, 32A breaker. Depends what else is in the trunking leading to it. If it is commercial will be used all the time so 2.5mm or 4mm is probably best avoided.

 

[pkonrad]

Thanks for the feed bk. Think I mite just go for 10mm to be sure as it's only a 5 meter run so won't b much different in price. Thanks again