Great video about generators, ground rods, bonding, etc.

[TurnThePage]

I have some ancient electrical training that was navy specific, so I was kind of fuzzy on some of the topics. This made it all easily understandable for me.

https://www.youtube.com/watch?v=viNZV0lyRVQ

[MrWizard]

Do not bond neutral to frame on a portable generator,
Yes use a bonding plug if you have too because of your ems, but physically permanently bonding frame to neutral , makes the generator frame and most likely your rv chassis part of the neutral side of the generator output circuit and creates a shock hazard, portable generators are mostly wired as floating grd unbounded for good saftey reasons

[ktmrfs]

TurnThePage wrote:
My impression is that we should probably always bond ground/neutral on our portable generators when using them to power our RVs. There's always lots of conversation about EMS systems requiring it.

yes, AFAIK ALL EMS systems will detect an open ground/neutral bond and usually not allow power to the trailer. Now depending on the EMS unit, one either needs a bonding plug, or for some units, just bypass the EMS when using a generator. My EMS unit has a switch to bypass. Usually I just plug in the bonding plug.

if you don't have an EMS, non issue. But it has caught many a new generator user trying to power a trailer with an EMS unit.

[TurnThePage]

My impression is that we should probably always bond ground/neutral on our portable generators when using them to power our RVs. There's always lots of conversation about EMS systems requiring it.

[BB_TX]

ktmrfs wrote:

………….
ALL a GFCI requires is an IMBALANCE between the hot and neutral, AND if a GFCI detects a ground/neutral bond downstream of the GFCI it will trip.
……

Ground/neutral bond is UPSTREAM of the GFCI(s), bonded at the source. Yes, the GFCI monitors an imbalance of the current flow between the hot pin and the neutral pin of that GFCI device. Ground fault (imbalance) means there is a connection between neutral and ground DOWNSTREAM of that GFCI device allowing some current flow to be diverted around the GFCI device and going back to the source. That means there is less current flowing thru the neutral pin than thru the hot pin. But the “leakage current” flow requires a closed circuit back to the source neutral. And that closed circuit is via the ground path to the neutral bond at the source, or with both the power source and the load side being independently grounded to earth so that earth provides that path. If there is no path from ground to the source neutral, there can be no “leakage current” flow and therefore no imbalance.

[ktmrfs]

BB_TX wrote:
GFCI is certainly an essential part of the overall power system. But it is secondary to his discussion on bonding and grounding. And GFCI protection requires ground bonding to neutral to function properly since a ground fault must have a path back to the power source for any leakage to bypass the GFCI devices and cause them to detect the fault.

Yes, GFCI is important,

NO GFCI does NOT require a ground bond to neutral or dedicated ground connection, in fact GFCI's are one if not the only) NEC code approved solution to a 3 prong outlet on a two wire (no ground) circuit in older house.

ALL a GFCI requires is an IMBALANCE between the hot and neutral, AND if a GFCI detects a ground/neutral bond downstream of the GFCI it will trip.

GFCI doesn't give a rip about what path the imbalance is taking, just that there is an imbalance which indicates an unintended leakage path. The current could be going through you, back to earth ground, back to the main transformer, it could be going through you to the house ground, between you and another circuit in the system, doesn't make any difference. And a GFCI is NOT a guarantee of protection against a shock. If you are between hot and neutral well insulated with no leakage, your not going to trip the GFCI. For all it cares, the GFCI thinks your just a lightbulb, toaster, TV etc.

In fact in most cases when a GFCI trips if you get across a circuit, it trips because of a ground path other than the installed ground wire. Your likely between the hot leg and a resistance path back through wet ground, etc.

[BB_TX]

GFCI is certainly an essential part of the overall power system. But it is secondary to his discussion on bonding and grounding. And GFCI protection requires ground bonding to neutral to function properly since a ground fault must have a path back to the power source for any leakage to bypass the GFCI devices and cause them to detect the fault.

[CA_Traveler]

X2 On the lack of a GFCI for common kitchen appliances considering his toaster example. And RV transfer switches switch the neutral and hots (not just the hots) and all ground wires are bonded in the transfer switch. A portable generator may have some amout of earth ground connection due to a wet earth area without a ground rod.

[ktmrfs]

He does a good job of outlining the bonded/not bonded and ground rod vs. no ground rod NEC requirements pretty clearly. I do quibble a bit with his implication that in a properly set up system that fault=breaker trip. As long as one doesn't overcurrent a fault won't trip a breaker, now a GFCI may provide that protection.

One thing he does do well is tie into NEC code requirements, especially the requirement that a home system have ONLY one ground/neutral bond and the difference between bonded and unbonded generators.

BTW I do have a transfer swith for our house in case power goes out, and configured for unbonded generators.