Re: Running a generator on a boat?
Coincidentally, I have a friend out on a gig today where they are using (or at least trying to use) a Honda EU6500 generator, which comes unbonded, apparently like the rest of the EU series. The reason for this is that they are designed for standby power for home use, and can be connected to your electrical panel, where ground and neutral are bonded inside your house. If neutral and ground are bonded on the generator as well, then the ground wire between the generator and service panel becomes a current carrying conductor, as half the neutral current will flow over the ground path.
This is also why the receptacles aren't GFCI. If they were, the current flowing through the ground wire in the above situation wouldn't be counted by the GFCI device, and it would immediately trip.
NEC 445.20 requires all portable generators with 120v outlets to be GFCI protected, however OSHA Article 29 CFR 1926.404(b)(1)(ii) exempts generators less than 5.5KW, which is apparently how the Hondas get away with not being GFCI protected.
Throwing more stuff into the soup, portable generators not used for standby power SHOULD have their ground and neutral bonded (not to mention they should have GFCI outlets), however the EU generators don't have an easy means of doing this internally - it apparently requires fairly significant disassembly to get to the location where bonding takes place.
There are different interpretations as to whether an external distro is a suitable place to bond neutral and ground together. One company in the film industry sells an isolation transformer where the secondary is to be grounded, providing the bond without modifying the generator.
Lots of interesting info here:
ScreenLight & Grip's E-Newsletter
and here:
Actual Continuous load of EU6500is
and here:
http://www.nfpa.org/assets/files/pdf/rop/70-a2010-ropdraft.pdf (generator section is article 445, grounding is article 250)
It would be really nice if this were a little more straightforward, and/or there was another choice of quiet, inverter-style generator that could be bonded without voiding the warranty or using third-party components. I would guess that Honda EUs are deployed incorrectly much more often than correctly.
The bottom line, as always, is the inspector wins.
