Wiring Honda Generator into Onan Connection Box

[Lateboomer1]

I have a 2200ie Companion Honda Generator with a 30 amp outlet, I would like to plumb it in to my current 50 amp transfer switch at the connection box for the Onan in the generator compartment. It would be really handy to have an outlet at the front of my trailer. That way I can leave the generator in the back of the PU and not have to lift it or drag out the heavy 50 amp cord. I've already installed a weather proof male 30 amp connection at the front of my trailer which I plan to wire into the existing junction box for the Onan.

Question: The factory wiring in junction box, has four wires, bare ground, netural (white), red (L1) and black (L2) (see Gen Connection Box image). Question is, do I use L1, or L2 with the Honda or do both legs require power?

Was going to have the shop take a look at it when I take it in for disc brake upgrade, but I believe this question can be easily answered by someone with a bit more experience than me.

Thanks,

 

Tranfer Switch Scmatic.tif

[Darryl&Rita]

Two choices; decide which power buss has the circuits you want powered, and connect the generator feed to that hot wire (red or black), or tie the red and black together, and connect to the generator feed. Option 1 will make it easier for you to keep track of what's being powered by the generator's 20 output, while option 2 means everything has the ability to be powered, and will require more awareness on your part. Use a 30 amp power inlet, 10 gauge wire between it and the junction box, and a 12 gauge extension cord from the generator to the inlet.

[oldjohnt]

"Question is, do I use L1, or L2 with the Honda or do both legs require power?"

 BOTH legs require power but ONLY to serve what appliances or receptacles are connected to them, L1 Red feeds some 120 Volt RV loads, L2 Black the others.

 Darryl & Rita, you may already know this ?? but your 50 Amp RV uses two legs of 120 VAC (240 VAC Line to Line, but 120 either Leg to Neutral) and one powers certain 120 VAC appliances in the RV (say the L1 Red) while the other (say the L2 Black) different 120 Volt appliances. IE a 50 Amp RV has two 120 Volt circuits, Red L1 feeds some Black L2 the others

 Obviously a 120 Volt genset provides only ONE leg of 120 so you could select which RV circuits for your genset to power (Red or Black) or else feed BOTH (tie Red & Black together) remembering you ONLY have a 30 amp generator IE you likely cant run say BOTH AC's if that's what your RV has, so you have to learn and pick and choose and limit use to the gensets capacity.  They make a 30 Amp Male to a 50 Amp Female Dogbone adapter for use in cases where the RV park (or say your genset) only has a 30 amp receptacle but you want to plug your 50 Amp RV, it simply ties Red L1 and Black L2 together so all circuits "work"

NOTE the Transfer Switch selects your source, be it the Utility orrrrrrrrrrrr a Genset when dry camping. I cant say from here exactly how it operates if a portable 120 VAC 30 Amp genset is used versus a larger onboard 120/240  50 Amp.

  IF YOU USE RV PARK 50 AMP POWER OR A 120/240 GENERATOR (like the Onan if it were such) DONT TIE RED AND BLACK TOGETHER !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

NOTE some gensets come from the factory with a Floating Neutral while others a Bonded Neutral. Your RV panel, UNLIKE a typical house panel, has separate insulated and isolated Neutral and ground Busses and in that case I would prefer a Bonded Neutral genset configuration.

Feed only one (Red or Black) circuit or both (tie red & Black) are choices BUT SUBJECT to the 30 Amp gensets capacity and/or how your transfer switch operates ??

John T  Happy and Blessed New Year yall

 

Edited January 1, 2021 by oldjohnt

[Kirk W]

Does the reference to the Onan box mean that you also have an installed generator from Onan? If you do, be very careful changing things that could impact the Onan. In this case I would put in another connection to the side that comes from your power cord. The safest way for you to do that would be to tie into the 50A cord and then use a 50a to 30a adapter between the new plug and your 30a cord. You don't want to tie L1 & L2 together in any way that would put them together when the Onan is in use. The safest way of all would be to install another transfer device on the 50a power cord side. 

[oldjohnt]

Yo Boomer, here's yet ONE OTHER OPTION even if its NOT an answer to your specific question....

If you simply plug your RV's 50 Amp 4 pin plug into Genset power using a 30 Amp Male (plugs into Genset) to a 50 Amp Female Dogbone Adapter (RV power cord plugs into it) you: 

1) Will have power to BOTH the RV's 120 Volt Legs. But ONLY 30 Amp service. IE limited use

2) The Transfer Switch will sense you have Utility Power (it don't know if its from a Genset or RV Park Pedestal) and shouldn't toggle/transfer to any onboard genset wiring.

Easy method, no re wiring, no extra Transfer Switches, just buy a 30 to 50 Dogbone Adapter and maybe a 10 to 25 feet as needed (less weight and bulk) 30 Amp three conductor RV extension power Cord.

NOTE if your Genset can produce 2200 Watts (and you use near that????) that's 18 Amps at 120 Volts, so I'd recommend 10 Gauge 30 Amp power cord versus a 12 Gauge 20 Amp rated. Per the NEC when I designed I only allowed 80% maximum continuous current of the conductors ampacity IE 80% of 20 amp = 16 and 80% of 30 = 24 Amps.  Even if sure less could still "work"

To avoid use of a heavy 50 Amp cord you spoke of, use a much lighter 10 Gauge 3 Conductor 30 Amp cord (only length needed) from the Genset to the RV placing the dogbone there at the RV.  

Don't have any shorts or connections in the junction box that wired to an onboard Onan.

The Genset should be configured with a Bonded Neutral same as a typical onboard genset is configured.

SURE if you still want to wire to that junction box instead, that can work, just follow my advice above. In that situation if the transfer switch sees no utility power (RV power cord not plugged in) but the genset connection is hot  (via your Honda genset and any adapters or wiring mods etc) the junction box and genset provides your electricity via the transfer switch.

I have given you lots of choices, theory of operation and guidance,  so now its YOUR decision. Feel free if you have more questions I will try my best to help

John T

 

[Darryl&Rita]

By the pictures, he only has a generator prepped RV, not one with a generator already onboard. From the original post, he's also looking to not drag the 50 amp cord around. Also, the front mounted power inlet would allow him to run the A/C while running down the road, assuming the A/C is powered by the wiring.

[Wrknrvr]

  The auto transfer switch should be set to generator when no external power is present.

  When external (shore power) is applied it has a magnetic transfer switch that disconnects generator power connection and switches to shore power.

 

   Since your rv is a 50 amp service, both red and black wires need to be connected together to power both L1 and  L2.      Now connecting them together will do the same thing as a 30 to 50 amp adapter.

 

  So stop right there.

 

  If you wire the front power receptacle  for a 50 amp input for a 50 amp cord. Then use a regular 30amp to 50 amp adapter between the new receptacle and your 30amp extension cord from your generator. that will solve another problem. If you ever need to hook up power at the front on 50 amp it is simple.

 

  This is assuming you do not have a generator already hooked to that auto transfer switch

 

  I have my fifthwheel setup that way. And have done a few others that way

 

   Vern in a T-shirt 

[Kirk W]

3 hours ago, Darryl&Rita said:

By the pictures, he only has a generator prepped RV, not one with a generator already onboard.

That clearly could change the game. I sometimes get nervous when we give technical advice to an amateur whose skill levels we have no knowledge of. 

[oldjohnt]

20 hours ago, Darryl&Rita said:

By the pictures, he only has a generator prepped RV, not one with a generator already onboard

That's so often the case here. Not being there or the poster not knowing himself makes it tough at times lol

Regardless, the electrical basics remain the same and he has been given several choices and examples of how to wire it, so now its HIS choice and he can use a much lighter probably shorter 30 Amp RV cord so he doesn't have to drag a long heavy bulky 50 amp cord around. 

Should he make a final decision we can add to our advice...

John T  Live from Arcadia Florida in the RV at a Bluegrass Festival

 

[Lateboomer1]

On 12/31/2020 at 8:06 PM, Darryl&Rita said:

Two choices; decide which power buss has the circuits you want powered, and connect the generator feed to that hot wire (red or black), or tie the red and black together, and connect to the generator feed. Option 1 will make it easier for you to keep track of what's being powered by the generator's 20 output, while option 2 means everything has the ability to be powered, and will require more awareness on your part. Use a 30 amp power inlet, 10 gauge wire between it and the junction box, and a 12 gauge extension cord from the generator to the inlet.

Darryl & Rita, Thanks for the information. That helps a lot and confirms what I have been thinking. I have everything needed to get-er-done, but will double check with an RV shop before I put power to the outlet.

[Lateboomer1]

On 1/1/2021 at 1:19 PM, Kirk W said:

That clearly could change the game. I sometimes get nervous when we give technical advice to an amateur whose skill levels we have no knowledge of. 

Kirk, not to worry. Even though I have a pretty good understanding of RV electrical wiring. I plan to have someone in the know check things out before I energize this thing. And no I dont have an Onan in the unit. Thanks for your concern...

[Lateboomer1]

Thanks to all of you who provided some great insight and helpful suggestions. I feel smarter, although my wife says I still look the same. Go figure....

Anyway I got -er-done and will have a professional take a look at my work before use. 

[jpatrickc]

I did exactly what you are planning except I didn't install the waterproof inlet I just wired a 15 foot #12 extension cord to the box and roll it up in the front storage compartment. Just wire the extension cord green (ground) to bare ground, white to white, and black to both the black and red in the box. I just leave the front compartment for ajar when I use the connection.

[oldjohnt]

11 hours ago, Lateboomer1 said:

 I plan to have someone in the know check things out before I energize this thing.

WISE CHOICE  Don't forget to configure the Genset with  a Bonded Neutral

Hope this helps

John T