HMI Cabinet Grounding Requirement

[philly]

I'm designing a new metal enclosed HMI cabinet which will contain 120V circuits brought to the cabinet. The cabinet is in an industrial site and will either be mounted on wall inside electrical room or just outside of room on a unistrut rack.

Besides the Equpment Ground Conductor (EGC) brought to the panel from the source of the 120V supply and tied to ground bar in cabinet, are there any other additional grounding requirements for a panel like this? Does it need to have a specific grounding electrode or any other connection to earth ground? Does it need to be externally bonded between cabinet exterior and any other ground reference points in E room or exterior?

 

[don_resqcapt19]

The code does not require anything other than the EGC. The instructions may require additional things, even a remote grounding electrode system, but no matter what, the HMI grounding electrode system and the power grounding electrode system must be connected together.

 

[JoeStillman]

Whatever you do, don't let anyone persuade you to install an "isolated ground" i.e. a grounding electrode that's not connected to the EGC.

 

[jim dungar]

In the old days we tried to do single point grounding instead of daisy chaining.

Start with a single ground bar at your source, run a dedicated grounding conductor to each remote panel. Do not run a grounding conductor from one remote panel to another.