Honda generator and electrical grid
Might I ask a question here unrelated to motorhomes? The topic of portable generators often comes up here and on other forums. I am thinking of buying the Honda "Companion" portable generator, and I a...
Forum Discussion
JaxDad wrote:
No, it does NOT do the same thing.
The ground and the neutral are bonded in the breaker panel and meter base. Backfeeding the house without breaking that bond means there is potential in the neutral wire beyond the meter base and back out into the grid.
A typical breaker doesn’t kick over with enough force to trip a second breaker, add to that the fact that it requires a massive overload to trip a breaker on a short circuit condition, not just a simple overload, like 5 times the normal load to trip.
If you haven’t transferrred the neutral, that massive overload could, and likely will, pass through the meter base and out into the grid.
I think you don't understand how the interlock works. It doesn't do anything to impede the tripping of a breaker. Rather, it makes it physically impossible to turn on or reset more than one of the interlocked breakers at any time. Before the generator one can be reset, the main must be disconnected, and vice-versa. It doesn't prevent or impede them from both being tripped simultaneously.
What you say about surges doesn't make any sense to me. Yes, the panel will typically bond neutral to ground (or, if not the panel, someplace at the service entrance they will be bonded together). That is the only place they get bonded; the generator output is floating otherwise. Any surges would be between the legs and the neutral, not between neutral and ground, and as the legs are disconnected from the rest of the grid (since the main breaker is off), they will not backfeed anything. Neutral will just sit at ground potential; indeed, it can't do much else since it's bonded to ground.
Incidentally, transfer switches for standby generators for houses do not typically switch the neutral line. Transfer switches for RV generator installations do because the RV panel doesn't bond the neutral and ground (as it acts as a subpanel when connected to campground power) and the RV generator does (so they are bonded when operating under generator power); it's needed there to maintain the standard that they are bonded at only one location.
The circuit breaker interlock systems are approved transfer switching mechanisms. The NFPA and UL accept them as safe for this application, and many of the dedicated manual transfer switch panels sold for household use employ circuit breaker interlocks as their switching mechanism. I'm very willing to believe that those organizations collectively have a better idea of what's safe and what isn't than you or me or any other posters here.
