View Full Version : Okay to bond ground to neutral on Honda eu3000is generator?
08-24-2012, 07:35 PM
The surge protector I have to protect my inverter and other electronics gives me an error message and shuts down when I power it from my portable generator, a Honda eu3000is. The problem is that the Honda has a floating ground. If I remember right, ABYC doesn't contemplate bonding of the ground to neutral at any place but the power source. The most simple fix I can think of is to jumper the outlet on my generator. Can anyone think of anything wrong with this approach?
08-24-2012, 09:38 PM
IMHO your boat can follow RV practices. In short you might consider bonding the ground and neutral inside the generator case for use on your boat. Read the blog listed below as his explanation makes sense to me.
The green grounding wire and white neutral wire should already be connected inside the generator. This is standard practice. As you said the are supposed to be connected at the source of power. I would do some continuity tests to see if they are. It may be that you have somehow lost the connection (broken wire, bad connections, etc) If you have lost the connection that would explain the problem with the surge protector because it doesn't have a connection on the grounding wire back to the source.
08-29-2012, 02:49 PM
Thanks OHB and Ike. I spoke with an engineer at American Honda. He said that Honda portable generators are, by design, manufactured with a floating ground. With no pun intended, I told him that shocked me. I asked what would happen if there were a malfunction with a grounded device that put 110v to the device's case and I touched that device while standing on the ground, or worse, in the water. I get that maybe I would be okay if the neutral didn't make it to ground, but the whole thing made me uneasy. I explained that with a "ground to nowhere," the device would have no chance to trip a breaker. He got a little defensive and told me that a floating ground is the "standard of the industry" for portable generators.
The concern has to be that someone will plug a portable into a house's panel, which would create an unsafe situation with a bond at the house's panel as well as at the generator. My guess is that Honda's lawyers told Honda that they are better being sued by RV and boat owners than homeowners. They may be right. Homeowners are more plentiful and are smart enough to avoid buying the hole in the water we call a boat.
I settled on a new plan to fix my situation. I will build a 12" long cord with a male Marinco plug on one and and a female Marinco receptacle on the other. I will create the white-to-green bond at the male end where I plug it into my generator's twist-lock outlet and plug my 30 amp extension cord into the female plug. Since the 12" cord will remain at my houseboat, no one can inadvertently plug my bonded generator into their house. The ends will cost me $100 or so, but it should be more idiot-proof than just putting a jumper in my generator.
I'm thinking that any safety-minded boat owner using a portable generator should consider this $100 modification.
08-30-2012, 08:24 AM
I did a little more investigation into why recent portable generators have floating grounds. This gentleman came up with the most understandable explanation.
If your portable generator is new enough it likely has GFCI (ground fault) protection on its outlets. HERE'S THE ISSUE with Bonded-Neutral: A GFCI functions by comparing the outgoing current on the HOT to the current coming back on the NEUTRAL. A difference of as little as 6/1000 of an amp will trip it out. If you have the NEUTRAL and GROUND bonded at 2 points (also called a loop), the current will SHARE the return path to the generator between the GROUND wire and the NEUTRAL wire. Since the GFCI sees less current on the NEUTRAL than on the HOT, it will trip out, rendering your generator useless for household backup. So, do NOT attach the generators ground wire to the transfer switch at all, but DO use a ground rod to attach to the generators frame. Hope that helps, Richard. (journeyman electrician).
Keep us informed of your results. Since the EU3000 doesn't have GFCI outlets your method should work.
Using portable generators on boats is IMHO an iffy proposition and just for the reasons you stated above, lack of a ground. Most of them have a provision for attaching a ground wire and a ground rod. But who does that? Supposedly if you set it on the ground or on bare concrete it is grounded, but how about on a boat? I have been asked this question for many years while working in the USCG Office of Boating Safety and have always replied DON'T. The only place for a portable generator is ashore, in an open well ventilated area, where they are safe. Manufacturers of these things do not recommend them for marine use. But I know what you are going to say, a lot of people do. A lot of people smoke while gassing up their cars too, would you?
see Portable Generators On Boats: Pro and Con http://newboatbuilders.com/docs/portable.pdf that I wrote in 2006. I might add that both the USCG and ABYC recommend you do not use portable generators on boats. It involves both a CO and a shock hazard. http://www.uscgboating.org/assets/pdf/recalls/BSC80.pdf#generator