1

I have already installed a interlock kit and reliance 30 amp inlet with 10/3 wire and a two pole 30 amp breaker. I also see there are pigtails you can buy to jump the single 120 volt wire coming from the Honda so the inlet and panel configuration would meet code. I don’t have any MWCB in the panel.

I do have two double pole breakers one to power the dryer and the other for the stove.

I will buy another generator if this plan won’t work but I really like the idea of not spending money on a new generator when the Honda is almost new.

Also I almost forgot to mention I have natural gas heat and water heater.

Well will it work?

4
  • Did a quick look, and this is a really expensive way to do things (except of course that it sounds like you already have this generator). EG4000 gives you 4000W instead of 3000W and it is 240V, and it costs ~ 30% less. The only catch is that it is not an inverter generator. Feb 28, 2021 at 5:55
  • 2
    I have about a hundred bucks invested in the inlet wire and breaker. I use the Honda when I camp with my trailer. It’s much quieter and probably more efficient than the eg4000. Thanks for the response but I’m most interested if the setup will work properly.
    – McNally
    Feb 28, 2021 at 6:15
  • Your idea should work but since a 2800W generator won't run very much of your home why not rearrange the breakers so the things you want on back up are on one phase? Then you're not creating a dangerous situation where a 240V generator plugged into your inlet would experience a short circuit, and any future MWBC circuits would have overloaded neutrals. I'm sure the pros will chime in but for those and other reasons I can't believe this would meet code. If the safety of your wiring requires your personal intervention during operation it is clearly against the very essence of any code!
    – jay613
    Mar 1, 2021 at 22:48
  • 1
    I don’t understand why plugging a 240 volt generator will short circuit. The modification is in the generator cord not the breaker box or inlet plug which were installed by a certified electrician and passed inspection.
    – McNally
    Mar 2, 2021 at 5:21

1 Answer 1

3

Yes you can power both legs of the panel from a single 120 volt source. Any 240 volt appliance won't work properly, and as you noted multi-wire branch circuits would be at risk of over-current on their neutral. Everything else should be fine.

One thing to check is the neutral-ground bond. Honda EU-series do not have a built-in neutral-ground bond. Make sure your system is appropriately bonded when switched to generator inlet mode.

Edit: More info about neutral-ground bond

Part of the reason we bring ground wires along with the line and neutral wires, at least in the USA wiring custom, is for safety. If certain kinds of electrical faults occur they could result in current flowing from one of the energized lines to earth-ground. Earth (dirt) isn't a great conductor, though, so the current won't be high enough to cause a circuit breaker to trip. Tripping a breaker is a good thing because it de-energizes the fault and because it calls attention to the problem. It turns out that if we "bond" (connect) the earth-ground wiring to the neutral then that fault current will be high enough to cause a breaker to trip.

There should be only one neutral-ground bond in a system. In a single-family home context that bond should be found in the first service panel -- usually the one where the electric meter is installed. It can take several forms: a screw that electrically connects a neutral bus bar to the housing of the panel, or a jumper wire between neutral bar and ground bar, or simply neutral wires and ground wires all landing on the same bus bar.

By definition all transfer switches switch the line conductors(s). Some also switch the neutral (and some switch the ground too? I'm not certain.). If a system has a 1- or 2-wire transfer switch, ie it switches only the line conductors, the generator connection should be arranged so that it does not introduce a second bond. With a 3- or 4-wire transfer switch, though, one needs to figure out whether the existing bond becomes disconnected by operation of the transfer switch.

In summary: it comes down to tracing wires. When the house is configured for normal grid power confirm electrical continuity (0-ohm resistance) between ground and neutral wires. Figure out where that connection/bond exists. Then configure the house for generator power, trace wires, and figure out whether that same ground-neutral bond is still in effect (and is the only bond), or whether there are 0 or 2+ bonds in the generator configuration.

4
  • Can you explain the neutral bond and how I check it?
    – McNally
    Feb 28, 2021 at 6:21
  • @McNally Additional info added.
    – Greg Hill
    Mar 1, 2021 at 15:10
  • I've seen lots of mentions of ensuring bonding and not having bonding in sub-panels, generators, etc. This is the first I've seen of what it really means & I really appreciate it! (Sure, I coulda gone and looked it up myself, but it was handy to come across it here.)
    – FreeMan
    Mar 1, 2021 at 17:19
  • Transfer switches never switch the equipment ground -- just hots and sometimes the neutral Mar 1, 2021 at 23:38

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.