3 prong 50 amp plug to 4 prong 50 amp ????

GoneCamping,

Any updates? It's always helpful when final solutions are posted to help newbies (and us oldies too!) learn from the experience.

Hope all is well.

~Rick

wildmanbaker wrote:

GoneCamping wrote:

If you run your 30 amp 115v camper on a 220 volt genset, you will smoke EVERY electrical product on board...

HUH? You telling me the Onan Genset that is onboard my RV will smoke everything? Tell ya what, if my factory installed generator will smoke everything, then it should have already done that 15 years ago.

Thanks for the help guys...

No, what I believe he is saying is that no RV generator produces 220 volts. Your entire RV runs on 120 volts. Even 50 amp Rvs run on 120 volts. Their have been persons on this forum that have supplied their RV with 220 volts by mistake, and cooked everything that was hooked up at the time. They are really trying to help you.

YOU said a 220 volt genny, I "assumed" from reading the rest of it that you had picked up a construction site genny that outputs 220 volts.

Your signature indicates a travel trailer, they don't have onboard genny's.

And Onan RV gensets DO NOT output 220 volts.
And 50 amp RV connections require a 4 pole plug.

Sorry for trying to help you, I'll be sure to never do it again.

And thanks Wildman!

I think what GoneCamping is talking about is faking the coach into thinking power is coming from the generator when in fact he will plug into the CG 50amp outlet.

Now comes the problem how do you wire the 4 prong CG side to the 3 prong RV side. There is NO provision for L1 & L2 in the RV only L1 - N and G so it can't be done the way he is attempting to do it.

What is not understood by GoneCamping is the rear AC is not fed through the 3 prong generator plug the 3 prong plug is electrically connected to the 30amp circuit breaker on the side of the generator and goes to the main coach 120V circuit breaker.
The 20 amp circuit breaker on the gen set is wired to the rear AC unit.

The generator puts out 1 120VAC 30amp output for the main coach and a separate 120VAC 20amp output for the rear AC unit. It is NOT 220VAC the 120V outputs are IN PHASE so the do not add up to 220VAC.

wildmanbaker wrote:
No, what I believe he is saying is that no RV generator produces 220 volts.

Just to be accurate here (and admittedly picking some nits :) ), there ARE some RV generators which produce 240VAC, but they are usually on high-end DPs and are 12 kW and above. Some of the high end rigs require 240 VAC for their appliances to work.

GoneCamping, your RV generator as equipped from the factory is 120VAC, NOT 240VAC. Don't let the dual breakers fool you.

~Rick

GoneCamping wrote:

If you run your 30 amp 115v camper on a 220 volt genset, you will smoke EVERY electrical product on board...

HUH? You telling me the Onan Genset that is onboard my RV will smoke everything? Tell ya what, if my factory installed generator will smoke everything, then it should have already done that 15 years ago.

Thanks for the help guys...

No, what I believe he is saying is that no RV generator produces 220 volts. Your entire RV runs on 120 volts. Even 50 amp Rvs run on 120 volts. Their have been persons on this forum that have supplied their RV with 220 volts by mistake, and cooked everything that was hooked up at the time. They are really trying to help you.

If you run your 30 amp 115v camper on a 220 volt genset, you will smoke EVERY electrical product on board...

HUH? You telling me the Onan Genset that is onboard my RV will smoke everything? Tell ya what, if my factory installed generator will smoke everything, then it should have already done that 15 years ago.

Thanks for the help guys...

GoneCamping wrote:
May not have been clear about this. It is NOT my intention to use the regular 30 amp shore cord at all, or to modify it in any way. I'm talking about simply not using it all, and instead unplug the coach cord going to the generator (220v 3 prong with locking tab on the neutral prong) and hooking into campground shore power via that cord fitted with 220v/50A shore power plug (instead of the regular 30 amp shore cord). Feeding off the genset 220 line is the only way the coach isolators will allow BOTH A/C units to run at the same time.

Again, I'm not talking about modifying anything at all on the coach, just using the generator 220v power plug into shore source instead of generated source. Should work...

I've wired a number of houses and all have passed electrical inspection, so like I said, I'm not a novice at this.

Really trying hard to make some sense of what you're talking about and most sure other's are, as well.
First bit of confusion is with your reference to a 220vac 3 wire genset output and don't know of any 30amp coach with a 220vac onboard generator. There is no 220v present anywhere on a 30amp coach, with the genset or otherwise.
Then you say that you're not going to use the cord, but unplug it from the genset and then re-plug it into the pedestal. If the cord is plugged into the genset outlet like it would be for a coach without a transfer switch, then this cord is the shore power feed and yes, you can use a 50/30 amp converter cord for feeding from a 220vac 50amp service outlet. This conversion, doesn't allow for any 220v to enter the coach. However, you are still running everything on a 120vac 30amp circuit with this method.
Keep in mind that the genset has a 20amp breaker that only feeds the rear ac via a relay and one that is bypassed when on shore power, so the rear ac breaker in the coach main box is now feeding the rear ac, rather than the breaker on the genset.

GoneCamping,

The generator plug you're talking about, is that the generator that came with the motorhome, or one you (or someone else) added? It's my understanding that motorhomes with 30A service (and even many with 50A service) have generators which put out 120V only. It might be two separate 120V feeds, but they are in-phase, not out-of-phase as needed to produce 240V. That's the way our 7 kW generator is wired in our 50A motorhome.

Just a thought to double check to make sure of your generator output voltage.

I think not having a ground is a bad idea.

~Rick

If you run your 30 amp 115v camper on a 220 volt genset, you will smoke EVERY electrical product on board...

Guys, screwing this up can be a DISASTER!

A 220 volt connection is intended to have 3 wires, L1 L2 and ground.
Neutral is not provided, nor is it needed.

An RV 30 amp connection also has 3 wires. Hot, Neutral, and Ground.
Neutral carries current, ground never does. (this is what makes a GFCI work)

Most S&B type 220v devices, stoves and ovens, and a/c's, don't have a neutral wired, because they have no use for it.

Your RV has no use for 220v, in fact it is very allergic to it. ALL current flow is from hot to neutral, or in the case of a 50 amp RV, from either L1 or L2, to neutral.

Do some studying on those twist lock connectors... there are a zillion of them, with many different uses.

BTW, the isolator will over-ride the shore power when/if the generator is producing power (not that it matters since I won't be plugged into shore power via the regular cord anyway)...