Min sizing of Motor Termination Box per NEC and or MG-1

[Dale001289]

I've got a large induction 460V, 3Ph AC motor that is being fed by 3-1/C 600kCMIL cable. The motor term box from the Vendor seems to be vastly undersized. What is the best way to calculate the min size required

 

[infinity]

I don't see how the NEC would apply to the peckerhead. The box is part of a piece of listed equipment.

 

[Dale001289]

But there should be something to address sizing - perhaps MG-1?

 

[infinity]

But there should be something to address sizing - perhaps MG-1?

MG-1? I would guess that NEMA standards would apply to some motors.

 

[Dennis Alwon]

Does 430-12 apply

 

[infinity]

Does 430-12 apply

I think that you may be on to something.

What wouldn't apply is the dimensions required for boxes in Article 314.

 

[jim dungar]

As infinity said, if the motor is a Listed device then NEC does not apply to its termination box.
If the motor is not listed the NEC should be used, as there is no other governing standard, as most of them, like MG-1, are voluntary.

 

[tom baker]

Can you order oversized motor junction box?
Are motors listed? I seem to recall only hazardous location motors were?

 

[retirede]

Can you order oversized motor junction box?
Are motors listed? I seem to recall only hazardous location motors were?

Oversized junction boxes are (used to be) available. I’ve even field-retrofitted one.

 

[Dale001289]

Can you order oversized motor junction box?
Are motors listed? I seem to recall only hazardous location motors were?

Tom, the motors are rated 841XL, Severe Duty for Class I, Division 2 locations but they're being used ONLY in unclassified areas.