Have a 35k generator on a fire truck.
We use a grounding rod, but have been told that it is not required.
Would like to know if it is required.

Thanks
Bill

According to the NEC Section 250.34 (B) a rod is not required only if the following conditions are followed:

1. The generator frame is bonded to the vehicle frame.
2.Gen only feeds the vehicle or corded devices from the receptacles on the vehicle.
3.The equipment ground for the receptacles are bonded to the generator frame.

I suspect all three conditions are in place, so no ground rod is needed.

You may want to check with the truck or genset manufacturer, and OSHA.