ECN Forum Forums Code Related Discussion NEC & other Code issues Motor Loads (check it out)

250 hp 480 volt three phase
302A
302x125%= 377.5 = 3-500mcm &Gr(per 250.122). 3 inch conduit
Breaker 600A.
125 Hp480 volt 3 phase
156 A
156x125%=195amps = 3-3/0 plus gr. 2 inch conduit
Breaker 250 amp
both either soft starts or VFD.
Wanna check my work guys.
Hair line between Pride & stupidy Right!!!

Numbers look OK to me.

Can you send me some Pasties? I could send you some Pepperoni rolls in return.

Tom

You mean the ones that go on yer Nipples.
:)))))

80-95% of the time my preference is to use soft starts for starting only applications and to save the VFD's for speed control.

Yoopersup,

I thought you were a uper, not a loper & I mean the ones you eat.

Tom

What kind of breaker?
What environment? Wet? Dry?
What ambient temperature?
What type of insulation on the conductors?
No mention of overloads.
Details, Ernie, details- You know how I am.