Grounding of machinery

[Danny89]

If I have piece of machinery that pulls 20 amps on a three phase 480v motor and a control panel that pulls 120v at 5 amps.

Does the frame of this machine need to be bonded to building steel to properly ground the equipment?

If so what size wire?
The building steel is bonded to ground via water pipe and ground rod.

My question is the equipment fine without frame being directly bonded to building steel? The motor does have a terminated ground in the peckerhead.
The controls box also has a terminated ground inside it's box also.

Those grounds ties into a main controls cabinet and that main controls cabinet at some point is bonded to building steel also.

Sent from my Moto Z (2) using Tapatalk

 

[tom baker]

Your equipment needs an Equipment Grounding Conductor -EGC- run with the circuit conductors.
Please review section 250.122 in the NEC.

 

[tom baker]

Moving to Grounding and Bonding

 

[Family man]

Are you saying that there is a transformer in the mix that would cause you to think that you need to ground a separately derived system to the building steel?


Sent from my iPhone using Tapatalk

 

[petersonra]

If I have piece of machinery that pulls 20 amps on a three phase 480v motor and a control panel that pulls 120v at 5 amps.

Does the frame of this machine need to be bonded to building steel to properly ground the equipment?

Simple answer is "No".

It does require an equipment grounding conductor as another poster mentioned.