50 AMP question

71_340 · 05-13-2021, 04:16 AM

I have another question since switching from a 30 to a 50 amp coach.

I seen that Camco makes a Y-connector cable/adapter that you can plug into the 30 amp and 15 amp outlets at the same time, supposedly giving you 45 amp service.

I am a mechanic, not an electrician. Does that really work?

Thanks from a 50 amp novice.

cavie · 05-13-2021, 10:04 AM

Quote:

Originally Posted by 71_340

I have another question since switching from a 30 to a 50 amp coach.

I seen that Camco makes a Y-connector cable/adapter that you can plug into the 30 amp and 15 amp outlets at the same time, supposedly giving you 45 amp service.

I am a mechanic, not an electrician. Does that really work?

Thanks from a 50 amp novice.

No, it does not. Most campground have 50/30/20 services. The 20 amp outlet is GFI protected. that y adapter you are talking about shares the neutral with the 30 amp side. GFI can NOT share a neutral. therefor it will trip the 20 amp gfi breaker every time. The other issue is if you have a 50 amp rig and you adapt down to 30 that's all well and good. Where are you gonna plug in the 20 amp side to get into your RV? How do you turn that 30 into 45?

DavidEM · 05-13-2021, 01:01 PM

Cavie is correct above, but let me explain how your 50A shore power works:

The 50A supply at campgrounds is actually a 240V circuit, which can be thought of as two 50A 120 circuits combined in one outlet to supply 240/120V. Your coach splits these into two 120V/50A circuits which power two independent 50A/120V busses with breakers to various loads.

Usually but not always I suspect one of the 50A/120V busses powers the air conditioner and the other 50A/120V buss powers the converter/microwave, electric stove if you have one, etc.

There should be no need for more power than a 50A/240/120V outlet can supply. You are getting the effect of 100 amps at 120V with that outlet.

If you ever camp at a site with just 30A and 15A available then that Y adapter might be useful, but one buss will be limited to 30A and the other will be limited to 15A. If you set it up so that the 30A circuit is supplying the buss for the A/Cs then it might run two A/Cs, but barely. The other buss will be limited to 15A which will power a microwave but probably not an electric stove top.

David

71_340 · 05-13-2021, 02:16 PM

Thanks for the answers. Like I said, one campground we use quite often has no 50 amp receptacles, just 30 amp and a regular household receptacle next to it but it is GFI.

No big deal, I just run one AC unit (have two 13.5K BTU units).

cavie · 05-13-2021, 03:01 PM

Quote:

Originally Posted by DavidEM

Cavie is correct above, but let me explain how your 50A shore power works:

The 50A supply at campgrounds is actually a 240V circuit, which can be thought of as two 50A 120 circuits combined in one outlet to supply 240/120V. Your coach splits these into two 120V/50A circuits which power two independent 50A/120V busses with breakers to various loads.

Usually but not always I suspect one of the 50A/120V busses powers the air conditioner and the other 50A/120V buss powers the converter/microwave, electric stove if you have one, etc.

There should be no need for more power than a 50A/240/120V outlet can supply. You are getting the effect of 100 amps at 120V with that outlet.

If you ever camp at a site with just 30A and 15A available then that Y adapter might be useful, but one buss will be limited to 30A and the other will be limited to 15A. If you set it up so that the 30A circuit is supplying the buss for the A/Cs then it might run two A/Cs, but barely. The other buss will be limited to 15A which will power a microwave but probably not an electric stove top.

David

the 15/30 y adaptor can not work. The 20 amp GFI outlet on the ped can not share the neutral with the 30 amp side. If the 30 and 15 were on different phases as they should be then you would have fireworks if you combined the 2. you can not add 30 and 15 and get 45 amps. 50 years as a master electrician I did learn that much.

Bob Denman · 05-13-2021, 03:05 PM

That Y-adapter is living proof of the power of marketing...

abjbrtd · 05-13-2021, 03:11 PM

Quote:

Originally Posted by cavie

No, it does not. Most campground have 50/30/20 services. The 20 amp outlet is GFI protected. that y adapter you are talking about shares the neutral with the 30 amp side. GFI can NOT share a neutral. therefor it will trip the 20 amp gfi breaker every time. The other issue is if you have a 50 amp rig and you adapt down to 30 that's all well and good. Where are you gonna plug in the 20 amp side to get into your RV? How do you turn that 30 into 45?

Simple math problem.
30 amp on L1 doing 30 amp stuff.
15 amp on L2 doing 15 amp stuff
= 45 amp stuff going on in mh

FYI don't get too excited, we're talking about a 100 amp MH

Chance · 05-13-2021, 03:31 PM

Correct. Those adaptors don’t combine L1 and L2. One leg gets 30 Amps and the other 20 Amps, hence it doesn’t matter whether on same phase or not. The motorhome doesn’t care either way (unless it has 240V appliances which most don’t). And the neutral won’t exceed 50 Amps even if on same phase, so that’s not an issue either.

The real problem is the GFI will trip, so a waste of time and money. A few will claim theirs worked, but that was probably at campgrounds that didn’t have GFIs, which doesn’t meet code.

TurnerFam · 05-13-2021, 10:56 PM

our 30/15-50a adapter works just fine, yes, giving you up to 50amps of usable power, if you have both a 30amp and a 20amp outlet to access, and the 15/20amp outlet is not a GFCI variety.
We've used ours several times, successfully, no matter what others say about it being 'impossible' to work, or some type of 'advertising' hype. It works. Simple. and no, most of the time you are not using it at a campground, it's more for situations off-grid or somewhere that does not have the typical 'campground' set of outlets.

They also make a 15/15/- 50 adapter, which is also nice to have.

TurnerFam · 05-13-2021, 10:57 PM

but, don't confuse 50amps of 'usable' power to be the same as your '50amp' coach, which is double that, since it is 240v service, not just 120v 30amps and 20amps.

TurnerFam · 05-13-2021, 11:02 PM

and, depending on 'how' the coach's breaker box is wired, yes, the two incoming power sources are separated at the breaker box, 30amps serving one 'side' of breakers, while the other 15/20amp serving the others. Some coaches, though, do NOT separate the power at the breaker box. If the adapter is used in that situation, though, the dryer will not work properly, because, after all, you aren't accessing 240v service.

71_340 · 05-13-2021, 11:49 PM

I sure didn't mean a big can of worms by asking that question.

Anyway, I know now that the Y-adapter will not work because the 15 amp receptacle at the campground we use is GFI. I will use a an adapter so I can plug my 50 amp cord into the 30 amp receptacle and just run one AC unit.

abjbrtd · 05-13-2021, 11:54 PM

Quote:

Originally Posted by Chance

Correct. Those adaptors don’t combine L1 and L2. One leg gets 30 Amps and the other 20 Amps, hence it doesn’t matter whether on same phase or not. The motorhome doesn’t care either way (unless it has 240V appliances which most don’t). And the neutral won’t exceed 50 Amps even if on same phase, so that’s not an issue either.

The real problem is the GFI will trip, so a waste of time and money. A few will claim theirs worked, but that was probably at campgrounds that didn’t have GFIs, which doesn’t meet code.

good job Chance

You finally got me going on 240v.
But we're both wrong this time

NO 240v in this thread at all!
Just (the same) 120v on bothering 30a and 15a outlets no L2.
So back to my original remark
30a on 1 outlet 15 a on the other outlet.
Plus the same common on both outlets...

GordSanClemente · 05-19-2021, 11:51 PM

As a side thought...

I added a soft start to each AC so that I could run our 2 A/C's off a 30AMP pedestal. I thought it made sense. Super easy to install.

TurnerFam · 05-20-2021, 12:00 AM

we've never adding anything, and can easily run both 13.5kw units off 30amps, with room to do other things, too...

**16ACE27** · 05-20-2021, 12:07 AM

I can run my 13.5K BTU and 15K BTU off 30 amps - not much else though.

TurnerFam · 05-22-2021, 12:01 PM

yep, and folks get tripped up over this '50amp vs 30amp' discussion all the time, since they've 'heard' someone say that it's not possible to do 'this' or do 'that' when only on 30amp service... crazy what people continue to spread around the world as 'fact' when they don't have any real-world experience in how it actually 'works'...

simple: if you plug in ANYTHING into an outlet, it will WORK, as long as it is not drawing more AMPERAGE than what the breaker on the other end allows. If you use your air conditioner, great. If you turn on the microwave at the same time, great. If you turn on the other air conditioner or some other large draw, all while that 'other stuff' is already working, then YES, you 'may' trip the 30amp breaker. Why? It's not because you 'can't' to this, or 'can't' do that while on a 30amp outlet, it's because you are ASKING for more power thru that connection than the breaker will allow, which is it's EXACT job.

Don't get caught up in what people 'say' you can and can't do. Do the research and learn for yourself, unless you simply just don't want to enjoy things to the fullest.

To give you some examples of this '30amp' limit that so many espouse, we came into a small rv park back several years ago, during the heat of the summer months. The owner said that the 'best' site for our rig, for the view, would be one with only a 30amp outlet. He immediately also 'reminded' me that he was sorry that I wouldn't be able to run both of my air conditioners. He was surprised that I was not concerned and that I even mentioned that I should be able to with no problem. He didn't believe me.
We plugged in, turned off the water heater and lowered the amperage draw for the battery charger, turned on both air conditioners, and even added some floor fans, while we left to take a walk up the mountain.
When we got back, the owner pulled up in his ATV asked if we were comfortable in the heat - I told him everything was great and both air conditioners were providing us great cooling. He was stunned. He hopped off and walked over to see our 'connection' at the pedestal, thinking that somehow we had someone added some new 'feature' to his electricity so that 'somehow' we could do something he had always 'heard' was impossible.
After some discussion, he eventually believed us, although he even stated that while he and his wife had traveled in their own motorhome for years, he had NEVER even TRIED to use both his air conditioners while on 30amp power - he had always been 'told' it was impossible.

Almost the next campground we arrived at later in the week was a similar story. This time, though, we initially did the same, but the breaker at the pedestal tripped. I did some research, and while 'we' were doing nothing different, the breaker was not holding. So, I stopped the manager who happened to be riding by on this golf cart. I mentioned that the breaker was 'weak' and asked if we could get a replacement. He immediately replied with the typical "oh, you'll never be able to do all that, anyway, you are trying to do 'too much' and it won't work"... but, being persistent, I asked again if he could at least give it a shot. He reluctantly agreed, called over his maintenance man, who basically also said the same thing about the situation, but he replaced the breaker anyway.
They were both SHOCKED when I came back out of the coach having turned on both air conditioners, and both remained working, while the conversation went back to the 'I'd always been 'TOLD' that it wasn't possible' point. Yep, even those who 'work' at campground don't always know how it works, they just 'assume' things because that's what they'd always been led to believe. The 'weak' breaker was the culprit, NOT the two air conditioners.

You may also like: