RV 30 and 50 amp service

[jastinjr]

Have Allegro 2004 MH. Question is it has a 50 amp power cord, but when I run the genny, I need to plug in the 50 to 30 amp pigtail. Also at some campgrounds I need to do use the 50 to 30 amp pigtail, even some rv rallys. I have found no problems doing this, and as far as I can see I can run everything in the MH ok, a/c, microwave, lights,refrig., the whole nine yards. So the real question is I'm about to install a rv outlet at the house to keep power to MH so it can run if needed, like company or remodeling work on house. Would it be ok to have a 30 rv outlet installed and run my 30 amp ext. cord to MH and use my pigtail to plug into the 50 amp service with no problems? Also is the 30 amp service at campgrounds 120 volts, as this will be what I will have at home?

[Gocoffeer]

If you are asking if you need to plug into an outlet when you run the genny? NOPE.... is the answer. If you are asking about the 30/50 amp difference... 30 amp is a 120v service....50 amp is a 240v service. You will not get enough power to run the rig as you would like if you were forced to use a 30 amp adapter....you only get about half the amperage that you would need. Hope that helps.

[John Hilley]

It sounds like you do fine on 30 amps. When you mention plugging in to generator, are you talking about external? 30 amps at home should work fine. The 50 amp actually provides two 50 amp 120 volt legs. The 30 amp is one 30 amp 120 volt leg. So 30 amp actually gives 1/3 the available current. I have a 50 amp motor home and 30 amp receptacle at home.

[jastinjr]

My ginney info says it's 33 amp output (onan 4000 micro quite). I have never been able to run anything in the MH without plugging it into the 30 amp outlet that is wired into the 50 amp box when the ginney is running. I have runned the whole MH before without problems. I think! So I guess that when I'm plugged into 50 amp service I'm really using all 50 amps?

[John Hilley]

Evidently you don't have a transfer switch. I am surprised that your Allegro doesn't have a larger generator and transfer switch, especially with 50 amp power cord.

30 amp RV outlet will be all you need at home.

[BFlinn181]

So, your RV a 50 amp RV or a 30 amp RV? You said it has a 50 amp shore cord, but you use a 30 amp pigtail to connect to your generator? Sounds like you don't have the generator wired into an Auto Transfer Switch and have to manually plug it in? That makes sense if the generator is 30 amp and the RV is 50 amp service. You said it's fully functional on the generator, so I assume you have no 240v appliances.

30 amp service is 3 wires, hot (120v) neutral, and ground. 30 amps @ 120v = 3,600 watts.



50 amp service is 4 wires, 2 hots @ 120v 50 amps (180º out of phase), a neutral, and a ground. 50 amps X 2 @ 120v = 12,000 watts. In the following diagram, you can see that each hot leg + neutral = 120v, but if the two hot legs are connected, they yield 240v.



Only all electric RVs that might have a 240v appliance really require 50 amp service to be fully functional. The rest of us on 50 amp service are using it at 120v but enjoy the flexibility of the 12,000 watts of power. Otherwise, energy awareness and management can utilize 30 amp service without popping circuit breakers.

You could have a 30 amp 120v outlet wired to your home and do all that you'd like except maybe turn on everything in the RV at once. Just be sure the electrician knows you want an RV 30 amp outlet. Electricians are used to wiring 30 amp outlets for dryers or kitchen ranges that use 30 amp 240v power.

[RickO]

Originally Posted by jastinjr

My ginney info says it's 33 amp output (onan 4000 micro quite). I have never been able to run anything in the MH without plugging it into the 30 amp outlet that is wired into the 50 amp box when the ginney is running. I have runned the whole MH before without problems. I think! So I guess that when I'm plugged into 50 amp service I'm really using all 50 amps?

It's a bit of a surprise that you've been able to run everything in the coach on 30 amps but if it works, then I see no reason not to make your home electrical hook up 30 amps. It'll save on the cost of the wire run.

Also, although the terminology is misleading... 30 amp service provides 30 amps of available power... but 50 amp service actually provides two 120v legs which EACH provide 50 amps... giving you a total of 100 amps available so it's quite a difference.

Rick

[JohnBoyToo]

My guess is that the generator was an add on and not from the factory if you have to plug it in ??!???

we might not be getting the whole picture


what does your original '50 amp' cord look like ?

This or This ?

[vsheetz]

If you were to run multiple air conditioners, the microwave, and a coffee maker all at the same time you might bring down a 30a breaker. Otherwise, 30a will be ok. Ideally you would install a 50a RV service, but given your experiences and usage, I would likely install the 30a and call it good.

[Tom-NC]

Hi,

I have to disagree with Mr Flinn as there are no 240V AC appliances in an RV. I repeat there are nio 240 volt AC appliances in an rv.

The 240 volt 50 amp is used to supply to different busses on the panel so that you can run a lot of things at the same time such as microwave and 2 air conditioners. Your wiring is correct and unless you know what you are doing, novices should not wire a 50 amp receptacle.

Now to answer the 50 to 30 amp. It would be nice first off to know what kind of Rv you have. Do you have a 30 amp receptacle in your power compartment and does your power cable hav a 30 amp plug as pictured by Mr Flinn? If the above is all 30 amp then you can install at your residence a 30 amp receptacle wired for 120 volts AC. If your Rv has a power cable with a 50 amp plug on it then you have to use the pigtail to plug it into a 30 amp receptacle.

It doesn't make sense that you would have 50 amp power cord with a 30 amp generator. Again what make and year is your RV?

[BFlinn181]

Originally Posted by Tom-NC

Hi,

I have to disagree with Mr Flinn as there are no 240V AC appliances in an RV. I repeat there are nio 240 volt AC appliances in an rv.

The 240 volt 50 amp is used to supply to different busses on the panel so that you can run a lot of things at the same time such as microwave and 2 air conditioners. Your wiring is correct and unless you know what you are doing, novices should not wire a 50 amp receptacle.

I added the bit about 240v appliances because I've been 'corrected' before when I've said that all RVs are 120v by folks that identify appliances installed that use 240v. Some folks would rather point out exceptions and muddy the waters instead of what is generally accepted practice.

I completely agree that the 50 amp service is used to make two distinctly different 120v busses in the service panel, but the potential is there to wire a 240v stove/range or dryer if wished. Of course they'd find some 50 amp pedestals unable to power their appliance if it was wired incorrectly.

I think we deduce from the OP his RV was 50 amp service but someone retrofitted it with a 30 amp generator with no ATS. The only fact that doesn't fit the 50 amp RV with 30 amp genny is his statement that "everything works" on 30 amp service. A deduction that the OP's RV was 30 amp and someone retrofitted it with a 50 amp shore cord could also be made. That would seem less likely since it requires a pigtail to connect to his genny and adds complications in his service panel. We'll have to await clarification from the OP.

[RickO]

Originally Posted by BFlinn181

I added the bit about 240v appliances because I've been 'corrected' before when I've said that all RVs are 120v by folks that identify appliances installed that use 240v. Some folks would rather point out exceptions and muddy the waters instead of what is generally accepted practice.

.

So true. I do seem to remember reading about some stacked washer/dryers and maybe an induction cooktop operating on 240V but it certainly is the exception rather than the rule.

Rick

[aauummm]

Originally Posted by Tom-NC

Hi,

I have to disagree with Mr Flinn as there are no 240V AC appliances in an RV. I repeat there are nio 240 volt AC appliances in an rv.

The 240 volt 50 amp is used to supply to different busses on the panel so that you can run a lot of things at the same time such as microwave and 2 air conditioners. Your wiring is correct and unless you know what you are doing, novices should not wire a 50 amp receptacle.

Now to answer the 50 to 30 amp. It would be nice first off to know what kind of Rv you have. Do you have a 30 amp receptacle in your power compartment and does your power cable hav a 30 amp plug as pictured by Mr Flinn? If the above is all 30 amp then you can install at your residence a 30 amp receptacle wired for 120 volts AC. If your Rv has a power cable with a 50 amp plug on it then you have to use the pigtail to plug it into a 30 amp receptacle.

It doesn't make sense that you would have 50 amp power cord with a 30 amp generator. Again what make and year is your RV?

This may help to explain his setup. I went to the Tiffin website and got the specs for the 2005 Allegro (they didn't have the specs for 2004):

"Standard equipment on all models:
• Fiberglass Front & Rear Caps
• Large Tinted Windshield
• 4.0 Kw Onan Generator (Will operate only one roof
A/C unit. Includes 30 Amp Service)
• 1 - 13,500 BTU High Profile Roof A/C (High Efficiency)"

It appears that someone has put a 50 Amp shore cord on the MH. I'm guessing that it has an EMS but the specs didn't say so.

[wa8yxm]

If you are installing an outlet at your home.. Either one will work

IF you are paying an ELECTRICIAN to install the outlet.. Have him do a 50

Multiple reasons

ONE: If you ever decide you NEED 50, you got it.

Two: The real reason: Many many are the threads that start "I hired an electrician to put in a 30 amp outlet and..... Sparkes Smoke, and occasionally fires resulted.. Hundreds of dollars in damage to the RV, because the electrician did it WRONG.

But I have seen exactly ONE such thread with 50 amp outlets, and it was a bit different: I plugged into the 50 amp outlet at the park and.....

Yup, park electrician needed a re-charge of his brain.

Just have him put in a 50, and it will be done right.