30 amp vs 50 amp service in the Home

[oatmeal]

Originally Posted by cbeierl

Another factor for me was that my whole house only has 100A service, so I really didn't want the RV to be able to use up half of that! The 30A service at home gives me everything I need, including the ability to run both ACs (although not at the same time as everything else in the coach).

FYI, what is known as "50-amp" RV service is actually 100 amps of power, so it wouldn't be capable of using all of your house's power, not half.

But I'm glad to hear there's somebody else out there who can run both ACs at the same time on 30 amps--so many people say it simply can't be done.

[cbeierl]

Originally Posted by cbeierl

Another factor for me was that my whole house only has 100A service, so I really didn't want the RV to be able to use up half of that! The 30A service at home gives me everything I need, including the ability to run both ACs (although not at the same time as everything else in the coach).

Originally Posted by oatmeal

FYI, what is known as "50-amp" RV service is actually 100 amps of power, so it wouldn't be capable of using all of your house's power, not half.

But I'm glad to hear there's somebody else out there who can run both ACs at the same time on 30 amps--so many people say it simply can't be done.

Yes, the 50A (240V) RV service is equivalent to 100A of 120V service, but similarly, the 100A (240V) household service is equivalent to 200A of 120V service.

[Solo_RV_Guy]

Originally Posted by oatmeal

FYI, what is known as "50-amp" RV service is actually 100 amps of power, so it wouldn't be capable of using all of your house's power, not half.

But I'm glad to hear there's somebody else out there who can run both ACs at the same time on 30 amps--so many people say it simply can't be done.

It's a 50 Ampere 240 Volt circuit with center-tapped "neutral" (or "Grounded current carrying conductor, in the Code). While you can use either side of the center tap to derive 120 Volt service, it's still a 50 Ampere circuit. What *can* be done isn't necessarily what it is... Yeah, it's semantics but different words exist for a reason.


As for running 2 air conditioners on a 30 Ampere 120 Volt service - sure, if they both don't start up at the same time it's entirely possible. Note that you'd need to be comfortable not using most anything powered by 120 Volts while doing so. No coffee maker, gas absorption reefer not on A.C., no battery charging, no hot water if the heater is electric.

[saddlesore]

Originally Posted by oatmeal

FYI, what is known as "50-amp" RV service is actually 100 amps of power, so it wouldn't be capable of using all of your house's power, not half.

But I'm glad to hear there's somebody else out there who can run both ACs at the same time on 30 amps--so many people say it simply can't be done.

Our former coach was a 30a coach, could run both (smaller ) roof AC's at the same time on 30a. However could not use the microwave if both AC's were running..would pop the breaker(s)

[Soppy]

Originally Posted by scotttz

I just bought a new class A diesel motor home. I want to plug in the motor home continuously to preserve the batteries. I want to have the electrician put a box right near my motor home so I don't have to run an electric cord from the garage all the way out to the driveway. The electrician I spoke with said he could put in 30 amp or 50 amp service. On occassion, I would run the AC's in the summer time. Should I have the electrician install 30 amp service, 50 amp service, or both? How much more money do you think it would cost to keep the motor home plugged into 50 amp service continuously (compared to 30 amp service continuously)? The real purpose of this is just to keep the batteries charged to maintain their life and probably to keep the residential refrigerator running continuously in the summer time.
Thank you
Scott

If you are getting an electrician to do the install , go for the 50 amp service. There will be lots of extra power available if you ever need to use it. You could easily run both A/C units, battery charger , fridge , etc. As for the operational cost , the cost of electricity will be the same for the 30 or 50 amp services with the same appliances in use. It's like having a coach with 600hp (50a) compared to one with 150hp(30a). You don't always use the 600hp , but it sure makes climbing hills a lot easier.

[followingsea]

Originally Posted by saddlesore

For just a few dollars more I strongly suggest that you put in a 50a/30a/20a box
Just be sure to use a licensed electrician and remind him/her that it is for an RV usage..


When we have guests, they get the S's & B's and we stay in the shack.. (also does "man cave " duties on "THOSE" occasions....

i agree for the same reasons.

i put in a 50a/30a/20a box on a property we use for the mh and a 30a tt.

the estimate for the house Las Vegas was $500 so i put in a 20 a outlet for $10 since it is not the place to be in a mh in the summer.

[aether_one]

Originally Posted by Ray,IN

How did you tie both legs together when they are 180° out-of-phase(split-phase) without burning out something? This explains split-phase quite well.
A 30A dogbone adapter is only wired to one leg = 120VAC, of a 240VAC - 50A receptacle, never both.
I will re-post the link previously supplied that explains wiring configurations for RV supply: RV Electric
Additional reading: http://www.samlexamerica.com/support...chCircuits.pdf

He only ran 30 Amp service but wired the single hot leg to both hot leg posts in the receptacle, essentially making the receptacle itself a 30 A to 50 A adapter.

[Ray,IN]

Originally Posted by cbeierl

It's a 120V 30A single phase circuit from the breaker box in the house (HOT/GND/NEUTRAL) and the single hot lead is connected to BOTH hot terminals inside the 50A socket mounted outside the house, giving the same result as if I'd used a 120V 30A socket with a 30A to 50A adapter plugged into it.

Now I understand, i was focused on a 50A 120/240V RV receptacle instead of your 30A wiring. Your wiring allows up to 30A on one leg or 15A on each.

[Solo_RV_Guy]

Originally Posted by tfryman

He only ran 30 Amp service but wired the single hot leg to both hot leg posts in the receptacle, essentially making the receptacle itself a 30 A to 50 A adapter.

That's a Code violation.

[cbeierl]

Originally Posted by tfryman

He only ran 30 Amp service but wired the single hot leg to both hot leg posts in the receptacle, essentially making the receptacle itself a 30 A to 50 A adapter.

Originally Posted by Solo_RV_Guy

That's a Code violation.

No, it's NOT.

[twinboat]

Originally Posted by Ray,IN

Now I understand, i was focused on a 50A 120/240V RV receptacle instead of your 30A wiring. Your wiring allows up to 30A on one leg or 15A on each.

No, its a single leg 30 amp 120 volt service. There is no other leg.

[oatmeal]

Originally Posted by cbeierl

Yes, the 50A (240V) RV service is equivalent to 100A of 120V service, but similarly, the 100A (240V) household service is equivalent to 200A of 120V service.

Thanks. I [obviously] had no idea. I managed to live in houses all my life and never gave a single thought to an amp, but living in the RV has me feeling like the episode of Green Acres where Oliver assigned a number for every appliance ("You Can't Plug a 2 In With a 6").

[oatmeal]

Originally Posted by Solo_RV_Guy

As for running 2 air conditioners on a 30 Ampere 120 Volt service - sure, if they both don't start up at the same time it's entirely possible.

Well, a lot of people said you can run only one air when on 30 amps; I was just trying to say that's not necessarily the case.

Originally Posted by Solo_RV_Guy

Note that you'd need to be comfortable not using most anything powered by 120 Volts while doing so. No coffee maker, gas absorption reefer not on A.C., no battery charging, no hot water if the heater is electric.

We leave the refrigerator on electric when running both air conditioner compressors. I've measured it on a Kill-a-watt and it's 440 watts. So it's the two airs, the refrigerator, and the usual TVs and satellite receivers and whatnot on 30 amps.

You just have to be careful not to use things that draw a lot of electricity, like the microwave or electric water heater or clothes dryer (although the Splendide on a wash cycle is fine).

I prefer 50 amps because it's easy, but in my coach (40-foot Alfa), anyway, living on 30 amps just takes a little bit of mindfulness. Storage on 30 amps, even if both airs were needed, would be a piece of cake.

[scotttz]

Everyone- thank you very much for all of your input. I will go for the 50 AMP service. Its worth the extra up front money for the install. I am glad that the cost of using 30A and 50A is not really much different.
BTW- this is really a great forum. Any questions I have are promptly answered and with in depth great explanations. More than anyone could ever ask for.
Thank you very much,
Scott