Short circuit protection for Soft Starters

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arts

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If two 50hp, 480 volt soft starters are to be installed in a single enclosure, what does the NEC require in terms of protection of the panel or connected loads?

My thoughts:
Provide a single fused disconnect for both motors and use time delay fuses sized at 125% of the total FLA of both motors with the disconnect switch installed in the enclosure with a through-the-door disconnect handle. Both soft starters being in the same electrical enclosure will be within inches of each other. I am not sure if the wire going from the soft starters will be within 10 feet of the enclosure but if they are I would size the wire for the 125% of the FLA of each motor. If it is greater than 10 feet I would size the wire for the total of the two motors' FLA.

Your comments are welcomed.
 
Are you asking if two interiors of soft start applications are to be installed in one enclosure and are they to be fed with one feeder?
 
ptonsparky said:
The installation instructions usually have pretty clear requirements for size & type of fuse.

You might look at Art 409 Industrial Control Panels.
Click to expand...

Exactly, the instructions have specific requirements on branch-circuit short-circuit and ground fault protection. They will list the acceptable type and size of the device.
 
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