I completely removed, moderately refurbished, and serviced this Onan. Every connection, wire, bolt and screw were returned to their original positions.

The very last connections are for the 120Vac system. I'm not certain about the LII leg as shown in this photo. Perhaps a look at your Onan will shed some light on this for me.

Thank you!

This photo illustrates my question:
http://www.gmcmhphotos.com/photos/data/6992/Onan_120Vac_Wiring.jpg

Interchange L1 and L2 as required so that the one that is grounded internally in the Onan is ground/neutral and the other feeds the hot side of the AC system.

A Hamilto wrote on Mon, 24 April 2017 16:21

Interchange L1 and L2 as required so that the one that is grounded internally in the Onan is ground/neutral and the other feeds the hot side of the AC system.

Mr. Hamilto, Thanks for the reply. This leads me to believe that whichever wire is the neutral for the 120Vac system, it should be common with the appropriate wire of the Onan that is neutral, and should be bonded to the Onan chassis.

It's clear which wire is "hot", in my case it's L1. I say that because the L2 wire is connected to the breaker and I don't think they'd put the breaker on the "neutral" side of the system.

Best,
Dave

If I'm not mistaken, with the 6 kW Onan power drawer, a single 120 Volt AC output is fed to BOTH the L1 and L2 terminals on the female power socket into which you plug the four-conductor power cable. The L1 and L2 wires of the power cable each feed separate circuit breakers to power 120 Volt circuits in the coach. This arrangement allows you to connect to 50 Amp 240 Volt power pedestals in a campground or a dedicated power 50A/240V circuit at your home! Once again, if memory is working, L1 and L2 wires in the CABLE are Black and Red. The neutral is White, and the safety ground is Green. That should be standard in a GMC coach, but there's no telling what aftermarket finishers did with a Transmode rolling chassis and shell.


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...There is confusion as these were available as 240 V for export and they did not relabel for domestic as I understand. You need to confirm which is from open breaker load side and which is chassis as previously mentioned above. It might be easier to refer to the hots at the 14-50R as X and Y. (I'm assuming you have a 14-50 and not TT-30.) The hot goes to X and a short jumper applies it to Y as well.

Per the Onan 6kW NH Major Service Manual, page 44, fig 57.....
L1 is what you guys are calling "HOT" and L2 is "NEUTRAL/GROUND" - unless someone has monkeyed around inside the generator's bellhousing..

L1 is a single conductor wire sourced from the compounding reactor in the bellhousing and then routed to the breaker on top of the generator.

L2 is two wires coming out of the bellhousing and crimped into a single lug and attached to a single wire going up the flex to the coach.

The L2 to chassis bonding that makes L2 the "GROUND" is shown at the lower left of Fig. 57.

The two "HOTs" on the 50A receptacle inside the coach's shore power cord cubby are bonded together and connected to L1 coming from the genset.

Note that unless you drive a ground rod at your campsite and then bond the coach's electrical ground to it while running the generator then the coach will never be at true electrical ground potential. It'll always be "floating" above true earth ground potential by an unknown amount that varies from instant to instant.

Once again: if some PO has monkeyed with the coach or genset wiring then all bets are off.

--Jim

Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH

I am going to believe what the Onan manual says (as reinforced by what I have seen with my own eyes while repairing them) rather than some diagram found on the Internet. In any case I expect that bdub diagram just has L1 and L2 mislabeled on the receptacle; the fact remains that the two hots on the receptacle are bonded and the neutral/ground conductors are bonded. And if the Onan has _not_ been messed with then the double-wire L2 is bonded to the Onan chassis and would serve as what we think of as a neutral/ground; OTOH the single-wire circuit-breakered L1 feeds the bonded "HOT" conductors in the receptacle.

> Repetition is good for young minds. So here goes again. Whatever comes out of the Onan circuit breaker is hot, and whatever else is left coming out of
> the Onan 120VAC wiring is neutral/ground.

The circuit breaker could be in either leg and be just as effective in interrupting current flow as it is supposed to. It would not be proper to have it that way - but it would work.

> But check with your multimeter before you assume anything.

Agree completely and the test is simple: check voltage between a bare metal spot on the generator chassis and each output wire. If the reading is 0VAC between the chassis and the wire then that's your "neutral". If it reads 120VAC then the wire is the "hot".

--Jim
Jim Miller
1977 Eleganza
1977 Royale
Hamilton, OH