50 amp more reliable?

[Phil G.]

When camping on hookups with our 30 amp motorhome, if we happen to be on a combination 30A/50A pedestal, I tend to use a 50A-to-30A adapter, plug the motorhome's 30A cable into the adapter, and then plug the adapter into the pedestal's 50A outlet.

My idea being that the pedestal's 50A power might be a more reliable and less trouble-prone way to access 30A power for the motorhome than using the pedestal's 30A outlet.

Does this reasoning and practice make any practical sense ... or is poor campground 30A power likely to mean that the campground's 50A power is also suspect?

[creativepart]

Don't think that the 30amp electricity is something different than the 50amp power.

30amp is one leg of 110v and 50amp is the same except there are 2-legs of 110v power. In most cases, the 50, 30 and 20 amp outlets in most CG pedestals are on the same 50 amp circuit.

[Morich]

From a small standpoint one might make some assumptions to say one is more reliable but those assumptions are pretty close to guessing until one knows far more about the park, it's maintenance and it's users.
If one assumes there are more 30 amp users than 50 amp and those users are more prone to making errors on hooking up due to tendency to be newer, more novice users, we could say that the 30 amp gets more use and abuse than the outlet for 50 amp. More wear and tear means less reliable but we need to look at those assumptions before accepting they are correct. A park which caters more to only the newer and larger buses may actually have very little use on the 30 amp outlet!
Then there is the question of who has done the design and install. A great looking park with all the features one could ever ask for may be outside limits where inspections are done and may be a pile of trash!
How things are maintained is also a prime consideration as things do wear out and how often and how well they are changed/fixed will make a lot of difference in what we use. When a wire corrodes or breaks, do they use good connectors that keep water out or do they just twist it back together real quick? Are the peds designed and built well to keep ants, mud daubers and rodents out or are they just a post that may have been run over a time or two?
Odds are good that the 30 amp and the 50 amp are both tied to the same wire inside, so I do not see much value in working too much to slant my use to either as I don't know much of the rest of the story and there is a certain amount of truth to the idea that every connection is a potential source of trouble.
If one outlet looks like a pit bull and the other a poodle, use the poodle if it is adequate?

[powercat_ras]

30 and 50 are almost always fed from exactly the same distribution box in the campground and in many cases they are fed using the same wires all the way to the pedestal. So if the power is suspect on one it's likely to be suspect on both.

The pro of plugging into the 50 with a 50 to 30 adapter is that the 50A breaker is in series with a 30A breaker in the RV. If you trip you'll always trip the breaker inside your RV and won't have to go outside to the pedestal to reset.

Plugging into the 30 you have two 30 amp breakers in series. Either one may trip first if there's an overload. In my experience with the WFCO power box that Winnebago uses, it seems that the pedestal breaker always trips first and you have to go outside to reset.

[Goodspike]

I agree with Creativepart. Although 50 is higher than 30, you're really only getting one leg of the 50, so in theory if it were actually a completely separate line (which it probably isn't) you're only going to get 25 amps. You probably would trip the breaker earlier with the 50 because drawing at or near 25 would trip it. The 30 is the way to go.

[Morich]

We made also be speaking of two different ideas of what reliable we want. If we are speaking of reliable as how often we trip the breaker on the post, the 50 has an advantage of sort for folks who only use less than thirty. If you want to know how it goes when your are running say 29 amps and plug in an electric heater, the 50 might be less likely to trip but you are still looking at several other safety items in the RV which are also meant to protect you. Tripping breakers is not a really firm and exact rating as the breakers do tend to triop quicker as they get older. Lots of really small points that normally are not something I sweat over. As much as factor of what everything and everybody else in the park are doing, more than which I plug into.

[Goodspike]

Originally Posted by Goodspike

I agree with Creativepart. Although 50 is higher than 30, you're really only getting one leg of the 50, so in theory if it were actually a completely separate line (which it probably isn't) you're only going to get 25 amps. You probably would trip the breaker earlier with the 50 because drawing at or near 25 would trip it. The 30 is the way to go.

I'm going to take this back because I've not looked at the breakers on a 50 amp RV service. I was assuming it was dual 25s, and if so, what I said would be correct. But if it's dual 50 breakers I would be wrong. That would be a considerable step up in power though, so I suspect it's dual 25 amp breakers.

[powercat_ras]

50 Amp RV service is NOT 25 + 25, it is 50 + 50.

50 Amp RV Pedestal Service is fed thru a 2-pole common trip breaker with each pole protected at 50 Amps. The poles are 180 degrees out of phase so that the common neutral wire used for both of the 2 feeds never carries more than 50 Amps.

30 Amp RV Pedestal Service is fed thru a 1-pole breaker protected at 30 Amps.

A 50-30 Amp Adapter only ties in to one of the poles of the 50 Amp Service.

[Goodspike]

Originally Posted by powercat_ras

50 Amp RV Pedestal Service is fed thru a 2-pole common trip breaker with each pole protected at 50 Amps.

Thanks, that's what I wasn't sure of because I've had no reason to look. That is a ton more power though, which is why I wasn't sure.

30 Amp RV Pedestal Service is fed thru a 1-pole breaker protected at 30 Amps.

Yep, knew that.

A 50-30 Amp Adapter only ties in to one of the poles of the 50 Amp Service.

Yep, knew that and said that above. But if that's what it is there's another reason to not connect that way. You should never connect a wire to a breaker that will burn up before the breaker trips. So either way what the OP does is not a good thing to do.

[powercat_ras]

It's OK to use a 50 to 30 adapter.

Yes, between the shore cable plug and the RV breaker box it's a 30 amp rated wire protected by a 50 amp breaker. But there is no where for that power to go except thru the 30 amp main breaker in the RV.

UNLESS the RV cord gets severely damaged and there is almost no real world scenario where it will fail in such a way where it would trip a 30 amp breaker but NOT trip a 50 amp breaker.

[Goodspike]

Originally Posted by powercat_ras

It's OK to use a 50 to 30 adapter.

Yes, between the shore cable plug and the RV breaker box it's a 30 amp rated wire protected by a 50 amp breaker. But there is no where for that power to go except thru the 30 amp main breaker in the RV.

UNLESS the RV cord gets severely damaged and there is almost no real world scenario where it will fail in such a way where it would trip a 30 amp breaker but NOT trip a 50 amp breaker.

So the 30 amp breaker in the RV is right where the line goes into the unit? If not, it's not okay.

I'm actually surprised that you can buy such a thing, except maybe at Harbor Freight.

[powercat_ras]

It's OK, 50 to 30 adapters are sold at over 5,000 retail outlets all over the USA everywhere camping supplies are sold. Goodspike, go ahead and reply and get the last word in, I'm done.

[Goodspike]

Originally Posted by powercat_ras

It's OK, 50 to 30 adapters are sold at over 5,000 retail outlets all over the USA everywhere camping supplies are sold. Goodspike, go ahead and reply and get the last word in, I'm done.

It's not okay. It's one of the basic rules of electrical wiring.

But I'm glad you're done, because you're giving out bad information. If you want to come back with some actual reason you're right other than you can buy something, have at it. Otherwise stay away.

[Goodspike]

Don’t use these Adapters
These adapters allow for the connection of a smaller cord to a larger source. The cord in this situation could be overloaded without a breaker tripping, which is a safety hazard. These devices cannot be UL-listed.

30-amp RV plugged into 50-amp source
Power adapter has 30-amp female receptacle (NEMA TT-30R) and 50-amp male plug (NEMA 14-50R) DO NOT USE!

https://rvnerds.com/2017/06/12/power-adapter-101/

[Morich]

Of these two sides to the discussion---- I have to come down on both sides as possibly right!
It is true that 30 amp wiring should not be used for 50 amp service, but then I don't know if that is totally a problem in this case due to things, I've not checked. Is the wire in the 30 amp cord sized small enough that it is not large enough to carry fifty amp? Never checked from that angle. It might be that the theory and fact don't quite meet and info found online from a source like RVnerds or any online site is suspect when I get down to really wanting the facts. Kind of like coming here and assuming all we read is totally correct. RV nerds is simply an ad site and is not any more accurate than any other site which operates for simple profit. I have to keep in mind that online is operated for profit primarily and passing on good info as secondary.
So the other side of the story is that there are lots and lots of these dogbones in use without being run off by legal beagles, so that tells me they don't often fail. Even the cheapest, worst items don't last long on places like Camping World if they are lawsuit bait!
So on logic and theory, I agree with Goodspike but on practical and what I see, Powercat also appears to be right. Man, setting on this barbwire gets touchy!

[Goodspike]

Originally Posted by Morich

Of these two sides to the discussion---- I have to come down on both sides as possibly right!
It is true that 30 amp wiring should not be used for 50 amp service, but then I don't know if that is totally a problem in this case due to things, I've not checked. Is the wire in the 30 amp cord sized small enough that it is not large enough to carry fifty amp?

I would guess it almost certainly is too small. I have a 30 amp generator for home use. My location of the generator to the power inlet is far enough away that I was worried about voltage drop over the distance. I had to buy my own cable and plugs to size the wire large enough where voltage drop wasn't an issue. I couldn't find anything pre-made. I went with 8 gauge, which I suspect means that 10 gauge was the largest I could find (and that is what one Campco cable I just looked at was). 10 gauge is not large enough for 50 amp use and 8 gauge is marginal.

But remember, the OP asked their question in this context:

My idea being that the pedestal's 50A power might be a more reliable and less trouble-prone way to access 30A power for the motorhome than using the pedestal's 30A outlet.

Basically they were doing it thinking it was "more reliable and less trouble-prone" when in reality it's a safety hazard, so more trouble-prone.

And sure you can say something is unlikely to occur. But what you cannot say is what that unlikely thing will be when it does occur. Where will the short be? What will be the nature of the short? And keep in mind it's not like RV wiring is known to be well designed and robust.

[orangeminnie]

30A cables generally use #10 wire. The twist-lock connection at the side of the RV is a common failure point. The #10 wire may get blistering hot (or worse) before blowing a 50A breaker. For safety, I suggest not using the 50A outlet unless the 30A looks badly worn. (If it is, make a stink at the office!)

[Goodspike]

Originally Posted by orangeminnie

30A cables generally use #10 wire. The twist-lock connection at the side of the RV is a common failure point. The #10 wire may get blistering hot (or worse) before blowing a 50A breaker. For safety, I suggest not using the 50A outlet unless the 30A looks badly worn. (If it is, make a stink at the office!)

Or use the 15 amp and limit your power usage. That would be safe. That may mean though no AC. Definitely no AC and microwave at the same time.

[Goodspike]

LOL, Camco claims their 50 to 30 amp adapter is rated for 3750 watts! ;-)

50AM/30AF PwrGrip 18" Dogbone

And this product is really questionable. I'm not sure they're wrong, but I don't see that you would get 45 amps by connecting to a 30 and 15 amp outlet. What would balance the load such that only 1/3rd the power was taken from the 15 amp circuit?

50Amp PowerGrip Power Maximizer Adapter

[orangeminnie]

Originally Posted by Goodspike

LOL, Camco claims their 50 to 30 amp adapter is rated for 3750 watts! ;-)

50AM/30AF PwrGrip 18" Dogbone

And this product is really questionable. I'm not sure they're wrong, but I don't see that you would get 45 amps by connecting to a 30 and 15 amp outlet. What would balance the load such that only 1/3rd the power was taken from the 15 amp circuit?

50Amp PowerGrip Power Maximizer Adapter

125v x 30A = 3750 watts
===
This weird dogbone assumes that the 15A outlet is on a separate circuit from the 30A outlet.
You're right that it's just the luck of the draw if the side that gets the 15A service would be the side that you use less load. Turn on both your ACs, and then a microwave, and see what pops.