Clients requirments

[IQ Electrical]

i would say you need to calculate the volt drop per phase , using 230V. so max. permitted per phase is 11.5v.

He's right with the 400 Volt calculation-it's based on line-line voltage so you use (assuming a balanced system) per phase VD X 0.866

 

[telectrix]

agreed. 20v line/line or 11.5v line/N. ( 11.5 x sq.rt.3 = 20 )

 

[Graham Coughlan]

Is Cg the conduit factors? if so i think i worked it out to be 474?

 

[Graham Coughlan]

agreed. 20v line/line or 11.5v line/N. ( 11.5 x sq.rt.3 = 20 )

wooah let me catch up... 5% x 230v = 11.5... Right got that...

I dont understand the rest of that

 

[telectrix]

3 phase, mate, 400v is rt.3 x 230

 

[IQ Electrical]

wooah let me catch up... 5% x 230v = 11.5... Right got that...

I dont understand the rest of that

It's using the single phase maximum volt drop figure multiplied by 1.732 (root 3) to get the 3-phase value.

Or to keep it simple, 5% of 400 Volts = 20 Volts