Electrical Management Systems questions
I'm considering installing a hard wired EMS. I recently saw a thread, that I can't find again, that implied these EMS systems will not work with an inverter generator supplying the trailer. I real...
Forum Discussion
cavie wrote:I disagree with this, and will just state why and move on. Both NEC and OSHA regs are pretty clear that the generator's frame replaces a grounding electrode, and the equipment grounding terminals of the generator's receptacles are to be connected to the generator frame. Unless there's an actual break in the equipment grounding conductor (ground wire), the EMS (or 3-light tester) is most certainly connected to the generator frame, yet diagnoses "open ground". Without an independent connection to the actual ground, the tester has no way of making a positive diagnosis.
One slight correction. It is diagnosing the situation exactly correct. Open ground. In a main service panel the ground and neutral are bonded together. Every panel after that is a sub-panel and the neutral and grounds are kept separate.
The generator is the Power Company and is the place that the neutral and grounds are bonded. Since the generator is not bonded, the ground is not connected. Think OPEN. Hence the OPEN GROUND indicator. Someday Gen manufacturers are gonna wake up.
As far as the manufacturers waking up goes, there are plenty of arguments that the floating output lowers the risk of shock in the event of a failure, the obvious example being if the outside case of powered equipment were to become "hot" while the user is in contact with an earth ground. There are opposite arguments, too. It's not a slam-dunk, clear issue for either approach.
