Grounding - NEC Standards

It will be difficult to make this pass. The extra connection will add resistance between the equipment and the ground. Even a straight wire will fail if it is too long.

The NEC code is based on a specific ohm maximum between the equipment and the ground plate.

Assumption from examples given is that the application is an equipment ground and not the power supply ground or neutral.

If so, both methods are acceptable.

If you route the ground as in example "A", you should CADWELD "T" bond the two conductors together with a correctly sized "pigtail" extension and then attach the pigtail to the enclosure grounding connection/bus. This will ensure that a "high-resistance" connection is not created and the conductor then will be able to maintain the required "low-impedance" (<.7ohm) equipment grounding path.

If you choose to use example "B", both conductors must be either "bonded" (CADWELD or similar method of welded connection) or bolted together at the common point with crimped or welded terminals if attaching to an existing grounding grid connection.

Why would the manufacturer provide a ground lug and a ground pad and not connect them? Ask the manufacturer what they recommend.

I think it depends on how your grounds are actually protection grounding. It looks like your controller probably separates itself from the main power system before it sends power to your motor. I vote for A because it would be the shortest grounding wire for the power system input and the controller output.

Earth ground is terminated at the service entrance or distribution point. The equipment ground is run with the circuit wiring and bonds all equipment along it's path. Don't hesitate to ask ths inspector how he wants the ground designed. He will appreciate the request and things will go much smoother.

250.24C1 "shall be routed with the phase conductors..."

Good luck,

James