Portable generator question (electrician)

shoelaceike · Mar 13, 2020

I got a 3000 watt generator years ago but never used it because I wasn't sure if it needed to be grounded and if it did, how to do it.

Now that I'm back in the hobby I would like to make sure I can use it if need be. Does it need to be grounded? There is a grounding nut on it.

redfishbluefish · Mar 13, 2020

OSHA Requirements for Portable Generators

****link fixed****

P-Dub · Mar 13, 2020

Per OSHA as I couldn't get that link to work @redfishbluefish
Under the following conditions, OSHA directs (29 CFR 1926.404(f)(3)(i)) that the frame of a portable generator need not be grounded (connected to earth) and that the frame may serve as the ground (in place of the earth):

The generator supplies only equipment mounted on the generator and/or cord and plug-connected equipment through receptacles mounted on the generator, § 1926.404(f)(3)(i)(A), and
The noncurrent-carrying metal parts of equipment (such as the fuel tank, the internal combustion engine, and the generator’s housing) are bonded to the generator frame, and the equipment grounding conductor terminals (of the power receptacles that are a part of [mounted on] the generator) are bonded to the generator frame, § 1926.404(f)(3)(i)(B).

Thus, rather than connect to a grounding electrode system, such as a driven ground rod, the generator’s frame replaces the grounding electrode.

If these conditions do not exist, then a grounding electrode, such as a ground rod, is required.

If the portable generator is providing electric power to a structure by connection via a transfer switch to a structure (home, office, shop, trailer, or similar) it must be connected to a grounding electrode system, such as a driven ground rod. The transfer switch must be approved for the use and installed in accordance with the manufacturer’s installation instructions by a qualified electrician.

Mine is connected to the structure via a transfer switch and the unit is grounded via a buried grounding electrode.