50 amp rv plug into 30 amp receptacle

[Martian]

Hi all. Not sure of the answer so better to ask.
When plugging a rig with a 50 amp cord into a dogbone to adapt to a 30 amp supply, does the dogbone merge the two legs of the 50 amp plug together?
Thanks for any help!

 

[RNS]

I believe it just uses one leg of the 50.

 

[Ex-Calif]

Yes the two hot legs should be tied together. You will be limited to 30 amps by the master C/B of the pedestal.



>>I believe it just uses one leg of the 50.<<

Both legs of the female 50amp need to be hot as the native 50 amp actually supplies 2 X 120V legs to the A/C power panel.

 

[Gary RV_Wizard]

The single 30A hot wire is connected to each of the two 50A hot wires (L1 & L2), so yes, they are "merged". If the adapter did not do this, half the 120v circuits in your RV would not work.
See the diagrams in Ex-Calif's reply.

 

[DonTom]

Hi all. Not sure of the answer so better to ask.
When plugging a rig with a 50 amp cord into a dogbone to adapt to a 30 amp supply, does the dogbone merge the two legs of the 50 amp plug together?
Thanks for any help!

Yep, you will get only 30 amps max, total. It is then used as one AC line, one neutral and one of the same hots on each line. 2nd line is not available on a 30-amp RV outlet.

Unlike when plugging into a 15-50R (50-amp RV outlet) where you have 100 amps total (50 amps each line).

With a 70-amp total difference between the so-called 30-and 50-amp RV outlets, you cannot run nearly as much stuff after you convert from a 30-amp outlet. Less than one third of the total power is available after the 30-amp to 50-amp plug conversation. Don't expect to still be able to run two A/C units and such but should be okay with only one running if not much other stuff.

-Don- Reno, NV

 

[Martian]

Thanks for all the replies. My goal is to keep two RV's plugged in for maintaining the batteries and reefers. One is 30 amp and the other is a 50 amp setup. Wanted to make sure the converter in the coach would have power as it is surely only hooked to one leg. Both will be into a y cable plugging into a 50 amp outlet with two 30 amp sockets. A 50 amp female to 30 amp male will go to the 30 amp plug. Sounds like it will work. Thanks again everybody!

 

[Kirk]

When plugging a rig with a 50 amp cord into a dogbone to adapt to a 30 amp supply, does the dogbone merge the two legs of the 50 amp plug together?

Simple answer is yes.

Both will be into a y cable plugging into a 50 amp outlet with two 30 amp sockets. A 50 amp female to 30 amp male will go to the 30 amp plug.

In this case you probably have one of these adapters?

You may have each 30A plug on a separate 50A leg but I would have to check it with a meter to be sure. If you measure between the hot pins of each 30A plug it will show 240V if on separate legs or 0V if they share the same leg. Either way, if all you want is to keep the batteries up and possibly use a few lights it should work as a shared leg would still allow about 15a each. If it is on separate 50a legs the RV limit for the 30A RV will be it's own main power circuit breaker.

 

[Martian]

That is what I am planning to get if the research works out.

 

[Kirk]

That is what I am planning to get if the research works out.

Amazon shows 2 different ones but so far I have not found any tech information for either one so am not sure how they are wired, although I suspect that they separate L1 to one 30a and L2 to the other 30.

CircleCord RV Y Adapter Cord 50 Amp to Two 30 Amp​

RVGUARD RV Y Adapter Cord 50 Amp 14-50P Male Plug to Two 30 Amp​

 

[NY_Dutch]

That is what I am planning to get if the research works out.

The adapter shown will work exactly as you expect. Each 30 amp outlet is powered a separate 50 amp leg, so each RV plugged in to it has a normal 30 amp supply. The only down side is that the 50 amp RV plugged in with a 30/50 dogbone does not have a 30 amp breaker protecting it, but without knowing the wire sizes used, that may not be a problem.

 

[Kirk]

Each 30 amp outlet is powered a separate 50 amp leg, so each RV plugged in to it has a normal 30 amp supply.

Have you verified this with one of the adapters? I would expect them to be that way, but have yet to get my hands on one to be sure.

 

[DonTom]

Have you verified this with one of the adapters? I would expect them to be that way, but have yet to get my hands on one to be sure.

If they are on separate lines, you should be able to get your 50 amps out of each of those two 30-amp adapter outlets, and that could be considered a safety issue.

That is the only reason I would wonder. Pull ~48 amps out of each adapter outlet and it will NOT trip either of the 50-amp CBs on the pedestal that now has 98 amps total on the two outlets, or 48 amps each possible, on 30-amp adapter outlets. That could be considered unsafe.

But if they are both on the same leg and you pull 30 amps from each, the 50-amp CB on that one side will trip. But you should still be good for ~24 amps on each side. Still more than the 30-amp total but then is considered safe.

But I would rather have the full 50-amps on each and take my chances, as I wouldn't ever use the 100-amps continuously anyway.

But they have to design this stuff idiot proof.

-Don- Reno, NV

 

[NY_Dutch]

Have you verified this with one of the adapters? I would expect them to be that way, but have yet to get my hands on one to be sure.

I have the exact one you pictured, and yes I have verified it. I expect all of them are made that way, since it's only thing that makes sense.

 

[DonTom]

I have the exact one you pictured, and yes I have verified it. I expect all of them are made that way, since it's only thing that makes sense.

Does that mean the 30-amp adapter outlets can really handle 50 amps each?

-Don- Reno, NV

 

[Tom]

Does that mean the 30-amp adapter outlets can really handle 50 amps each?

-Don- Reno, NV

Of course not.

 

[DonTom]

Of course not.

I don't see why you say that. "30-amp" could be just a name, not a true rating.

Besides the fact that you could pull 50 amps from each of the dual 30-amp adapter outlet without tripping either of the 50-amp pedestal CBs.

It just doesn't add up as being safe if your "of course not" is really true.

-Don- Reno, NV

 

[Gary RV_Wizard]

Have you verified this with one of the adapters? I would expect them to be that way, but have yet to get my hands on one to be sure.

I used to own one and it was wired as described here, but that is no guarantee that every Y-adapter is wired the same way. It would be silly not to, and there is no cost saving or other benefit of not using both L1 & L2, but I've seen idiotic designs before.

 

[DonTom]

It would be silly not to,

So you're saying it's okay to draw 50 amps out of a 30-amp adapter outlet without any CB tripping?

-Don- Reno, NV

 

[NY_Dutch]

Does that mean the 30-amp adapter outlets can really handle 50 amps each?

-Don- Reno, NV

Since I don't know the wire sizes used for each 30 amp outlet, I can't definitively say that. In the OP's case, there's also the 30/50 adapter wire size to consider. The reality though, is that each leg of the 50 amp outlet is protected at 50 amps, so the 50 amp RV plugged into one of the 30 amp outlets via an adapter could draw up to 50 amps, although the wire would likely heat up and possibly fail. The 30 RV plugged into the other 30 amp outlet would be protected by it's own 30 amp main breaker of course.

 

[DonTom]

so the 50 amp RV plugged into one of the 30 amp outlets via an adapter could draw up to 50 amps.

My question is really about the 30-amp RV outlets themselves. Can they safely handle 50 amps (if the wire to them can). And if so, can it be a continuous 48 amps?

I assume it's probably not much of an issue as long as there is no juice when plugged in and removed as long as it's a good connection when used.

I just am not sure what the rating means--or even if the rating on a plug/outlet is really the max current it can handle, even if off when plugged in or out.

-Don- Reno, NV