Motor grounding requirement??

[Mporter4]

I have a 3-phase ,480v,10 hp motor in a hazardous location class 1 div 2 and a question was brought up about a secondary ground that is tied from the motor frame to structural steel;Is this an nec requirement or a like to have?

 

[bphgravity]

This is not an NEC requirement, nor will it serve any purpose.

 

[haskindm]

Agreed. For what it is worth.

 

[zog]

Is this an ungrounded Delta system?

 

[Mporter4]

no it is not.

 

[zog]

Then I agree with the 1st two answers you got, not required, no purpose.

 

[don_resqcapt19]

Zog,
Why would it change if the supply was from an ungrounded delta system?
Don