Industrial Grounding of Equipment and Enclosures

[dbuschor]

After reading section 250, I get confused as to what is required for grounding.

Case: 480V Main Control Panel (MCP) with a PLC, 2 VFDs, 3 full voltage starters, and 110V AC & 24V DC instruments. The MCP services modular skids containing motors and instruments. The MCP to be fed with 3/C with ground rated for 200 Amp service.

Can the ground above be carried out to the skids (via a ground buss in the MCP) for grounding the motors and instruments? Or do the motors and instruments have to be grounded via a separate building ground?

What about non-current carrying equipment such as vessels, tanks, machine frames etc mounted on concrete pads. Can the ground above be used? or is a separate building ground required?

 

[don_resqcapt19]

Re: Industrial Grounding of Equipment and Enclosures

The grounding for all electrical equipment must originate at the power source for the equipment and be run with the circuit conductors. The other equipment should be tied to the electrical grounding system to avoid any potential differences. If a second grounding system is installed for the nonelectrical equipment, it must be bonded to the electrical grounding system.
Don