3P MACHINE WIRING CHECK

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florida-sparkey

Senior Member
Location
Pinellas Park, Florida
Occupation
Master Electrician
Hello,
I have a 3 phase machine to wire. Please check my calculation if you don't mind.
Unit has lots of small motors and water pumps. I do not intend to 125% the circuit because I assume the engineers did so when creating the data tag. However it does not state MCA so please tell me if I am wrong and should increase the circuit to 125%.

Circuit length is short, about 60 feet.

Control module has internal disconnect and is within sight of the panel. (no disconnect needed)

I am wiring to a 240V delta service (unit has internal xformer for voltage conversion)

Data tag on control module states 208V 120A 60Hz.

I am converting data tag voltage to the applied voltage to size my circuit-
208V x 1.732 x 120A = 43231VA
43231VA / (240V x 1.732) = 104A

104A circuit size.
Circuit size 1/0 AL or #2CU with #6CU EGC

Thank you for your time!!
 

jumper

Senior Member
Math is correct, I did not check wire sizes.

I would be hesitant to assume MCA is built in the data value. RFI the engineering staff who speced it.

Higher voltage does not always mean less current for non resistive loads.
 

florida-sparkey

Senior Member
Location
Pinellas Park, Florida
Occupation
Master Electrician
Math is correct, I did not check wire sizes.

I would be hesitant to assume MCA is built in the data value. RFI the engineering staff who speced it.

Higher voltage does not always mean less current for non resistive loads.

Thanks Jumper! The one wire size also increase my conduit but I think I will just go big or go home. Your non resistive load comment is what did it for me.
 
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