| Onan 120v Wiring Gauge [message #281582] |
Mon, 06 July 2015 18:47  |
bhayes
Messages: 263
Registered: March 2010
Karma: 1
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What gauge wire runs from the Onan to the 50 amp outlet? One of our coach's POs cut the original wire that runs through the armored conduit and installed a stranded wire that runs through hole drilled into the back wall of the generator compartment, up under the seat in the rear, behind the closet, and then finally into the 50 amp outlet (without a cable clamp to hold it to the junction box). It looks like a temporary job that became permanent because it initially wasn't even connected to the Onan's circuit breaker. Needless to say, I'm not enthused about it. I'm concerned that the wire gauge is too small, in addition to the unprotected route it takes.
I think the conduit is still intact, so I'd like to pull wire back through the conduit and reconnect it correctly. Some of gauge/amperage charts I've looked at recommend 6 gauge wire, and I'm assuming that's for stranded wire. Is this correct?
Bryan Hayes
'76 Eleganza II
Salt Lake City, Utah
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| Re: Onan 120v Wiring Gauge [message #281584 is a reply to message #281582] |
Mon, 06 July 2015 19:27  |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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I have mine appart now and there are 2 #6 wires in the armoured casing. If the breaker is 50A at the Onan you really need the 6 ga. You can't safely go to a 30A cord unless you change the breaker to 30A With the stock set up the shore cord when plugged into the Onan 14-50 recept splits the load on the 2 hots as they are paralled, but the Neutral carries up to the full 6000W of the Onan. Coiled up in the compartment it gets hot due to lack of air circulation and possibly some inductance. This is less problematic when on 14-50 shore power as the phases balance and reduce the Neutral current as well as being in free air and not coiled up. Fires suck, follow codes.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: Onan 120v Wiring Gauge [message #281588 is a reply to message #281582] |
Mon, 06 July 2015 19:43 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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If you learn how to "over-under" the cable into the compartment it will then come out with zero twists. All multiple conductor cables should be coiled this way to prevent dammage as should your garden hose and air hose in the shop.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: [GMCnet] Onan 120v Wiring Gauge [message #281589 is a reply to message #281583] |
Mon, 06 July 2015 19:42 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Steve,
First off, why do you have a 50A cord set in the first place? Is your 23'
not a Birchaven? Isn't your Onan a 4kW? With only one A/C, a 30A cord set
should be more than adequate -- at least I've never needed more, even when
running everything in the coach simultaneously (except the A/C & space
heaters). I'd be making haste to convert to 30A service. Mostly to get
rid of the 50A cable, but also because it makes the wiring so much
simpler. For example, an automatic transfer switch for 30A is about 1/3 as
complex and expensive as one for 50A.
JWID,
Ken H.
On Mon, Jul 6, 2015 at 8:05 PM, Steve Weinstock
wrote:
> Bryan -
>
> Sorry for a slight hijack - but here's a related question:
>
> What's the consensus on replacing that big bulky 50A cord with a more
> flexible 30A cord ??
>
> And if I do that - should I replace the recepticle from the generator or
> just use a converter plug ??
>
> And what's the proper wiring for going from a four prong to a three prong
> connector ??
>
> I've got a 23 footer with a single air conditioner...
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: Onan 120v Wiring Gauge [message #281648 is a reply to message #281582] |
Tue, 07 July 2015 11:54 |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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bhayes wrote on Mon, 06 July 2015 18:47What gauge wire runs from the Onan to the 50 amp outlet? One of our coach's POs cut the original wire that runs through the armored conduit and installed a stranded wire that runs through hole drilled into the back wall of the generator compartment, up under the seat in the rear, behind the closet, and then finally into the 50 amp outlet (without a cable clamp to hold it to the junction box). It looks like a temporary job that became permanent because it initially wasn't even connected to the Onan's circuit breaker. Needless to say, I'm not enthused about it. I'm concerned that the wire gauge is too small, in addition to the unprotected route it takes.
I think the conduit is still intact, so I'd like to pull wire back through the conduit and reconnect it correctly. Some of gauge/amperage charts I've looked at recommend 6 gauge wire, and I'm assuming that's for stranded wire. Is this correct? For NEC Compliance (and with all due respect for those that say you can get by with smaller gauge wire): A 6k Onan has a 50A breaker, so the wire needs to be 6 gauge to be able to handle 50A, whether it ever actually handles that much or not. That includes both the wire from the Onan to the 50A outlet AND the shore power cord, which is often connected to the 50A Onan outlet. A 4k Onan has a 35A breaker, so the wire needs to be 8 gauge (good for up to 40A). If you want to run 10 gauge wire, you SHOULD replace the Onan breaker with a 30A. When GM was upfitting motorhomes, they probably had one bin of cords rated for 50A, so all GM upfitted models would have a cord rated for 50A. Can't have a bin of cords rated for 40A and a bin of cords rated for 50A, when some high-school drop-out assembler will grab a 40A cord and stick it in a 6k Onan unit because the 50A cord bin was empty.
Once it gets above 10 gauge solid wire is too hard to bend so about all you can buy in larger gauges is stranded.
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| Re: Onan 120v Wiring Gauge [message #281666 is a reply to message #281632] |
Tue, 07 July 2015 14:52 |
bhayes
Messages: 263
Registered: March 2010
Karma: 1
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Senior Member |
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SteveW wrote on Tue, 07 July 2015 08:35Thanks for the comments !
Ken - GMC built 1973 23 footer. Not a Birchhaven. And no transfer switch - either plug in to the generator recepticle or shore power recepticle. I'll check the circuit breakers for proper sizing and go with a 30A cord for ease of use... Yep - 4K Onan.
Gene - Thanks. I'll be in your neck of the woods in a few weeks...
Bryan - apologies again for the hijack. Is your wiring question answered well enough ??
Steve W
1973 23'
Southern California
No problem, good discussion. Looks like I'll need to run 6 gauge wire. Thanks!
Bryan Hayes
'76 Eleganza II
Salt Lake City, Utah
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