Upgrading from 30 amp to 50 amp service

Also, by doing that you are setting yourself up for a possible voltage drop problem. The NEC only requires a demand factor of 3600 watts (30 amps) for a pedestal with 30 and 20 amps on it and the wiring to a pedestal is sized based on 3600 watts. Because of the way older CGs were wired they could be a voltage issue, but newer CGs are loop-fed and you'd likely be okay.

For 50 amp service you need a dual 50amp breaker allowing the RV to use 100amps (50 amps per leg). Bringing in 50 amps and dividing it between a 30 and a 20 is not 50 amp service. I may still not be understanding correctly but that's nothing new for me!
It's much like the cheater boxes that let you plug a 50 amp coach into 2-30 amp plugs at the campground. This is great when 50 amp is not available but it only gives you 30 amps on each leg (a total of 60 amps) vs. true 50 amp service which provides 50 amps to each leg (a total of 100 amps).

No 230v appliances in the RV
All appliances and circuits are 120v

Bill.Satellite wrote:

TNGW1500SE wrote:
Why not just upgrade the RV to 50 amps? I did it on my TT. You can always adapt it to a 30 if that's all the is at the campsite. I added a new panel and used the old panel as a sub. I feed the old panel off a 30 amp breaker in the new panel using the old 30 amp cord. Then I removed the 20 amp A/C from the old panel and put it on a 20 amp breaker on the new panel. The most expensive part was the wire but if you watch Craigslist, you might find a RV extension cord that you can use if you cut the female end off of it. If you get the A/C off the 30 amp panel, that frees up a bunch of amps for other things. It solved any lack of amperage issues we had in the TT. I may do it again in the class A, but for now it's ok. I'm in the middle of other projects!!!!!

I am not sure that I understand what you did, but 50amp service provides up to 100 amp (12,000 watts) not 30 amp plus 20 amp (50 total amps, 6000 watts).
Upgrading a 30 amp coach to a 50 amp coach can certainly be done but the total price required to do so may catch some owners off guard.

My TT mod didn't use the 220 that a 50 amp outlet is capable of but does any RV use the 220? Doesn't an RV just use both phases as 110?

I could have used the 220 if I'd wanted to (for maybe a heater) but I wanted to be able to adapt to 30 amp outlets (if that's all there was) and the 220 heater wouldn't work using only one phase (as when using a adapter plugging a 50 amp into a 30 CG outlet).


Here's what I did and it worked great.

I installed a new 50 amp four space panel in the rear of the TT back where the existing cord came in.

Used a new 50 amp cord.

Attached new 50 amp cord to a 50 amp breaker in new panel (used as a main)

Wired one phase to the old 30 amp panel using new 30 amp breaker in new panel so the old 10 gauge wiring is still protected by 30 amp breaker.

Wired the other phase to the old 20 amp A/C circuit (also wired this phase to a new outlet for portable heater) using new 20 amp breaker in new panel.

New panel used 3 breakers: one 50 amp 220 breaker, one 30 amp 110 breaker, one 20 amp 110 breaker. (Could have added more breakers as needed to the new panel but didn't) All I needed was to get the A/C off the old panel.

The above mods removed the A/C (and elec heat) load from the original 30 amp panel allowing those loads to be powered off the other phase. Also freed up one breaker in the old panel. The old panel is now a 30 amp Sub Panel feed by the original 10 gauge wiring.

The A/C and or electric heaters are the largest loads. Just getting those loads off the old 30 amp panel fixed any issues the TT had tripping breakers and the main (now 50 amp) is now back in the new panel.

No more turning off the A/C to make toast, microwave oatmeal or dry your hair!

MrWizard wrote:

GordonThree wrote:
If using an extension cord, how would it be possible for the two different hots to come together? Are folks using a cheater cable and back feeding the panel somehow?

the hots Don't come together 'too risky', No back feeding
if you have a 30amp RV, the 20amp will be a separate circuit not connected to the RV panel and 30 amp input, a separate outlet to plug an appliance/item into, good for portable heaters etc..

if using an adapter box to feed a 50 amp RV

you have (2) different feeds going to (2) different hot legs

one leg in the RV will have 30amp available, the other leg will have 20amp available

That's what I thought, and why I wondered about the "hidden danger" post on the first page.

Bill,

I believe he has a 50A shore cord feeding a new 120/240V panel. This panel has a 30A CB feeding the original rig panel and a new 20A CB for whatever. The new panel has the capability of more CBs as desired and hence up to 12KW. This setup provides more power when connected to a 50A pedestal.

But when using a 30A pedestal it doesn't provide the 30+20 (6KW) capability of a second cord.

TNGW1500SE wrote:
Why not just upgrade the RV to 50 amps? I did it on my TT. You can always adapt it to a 30 if that's all the is at the campsite. I added a new panel and used the old panel as a sub. I feed the old panel off a 30 amp breaker in the new panel using the old 30 amp cord. Then I removed the 20 amp A/C from the old panel and put it on a 20 amp breaker on the new panel. The most expensive part was the wire but if you watch Craigslist, you might find a RV extension cord that you can use if you cut the female end off of it. If you get the A/C off the 30 amp panel, that frees up a bunch of amps for other things. It solved any lack of amperage issues we had in the TT. I may do it again in the class A, but for now it's ok. I'm in the middle of other projects!!!!!

I am not sure that I understand what you did, but 50amp service provides up to 100 amp (12,000 watts) not 30 amp plus 20 amp (50 total amps, 6000 watts).
Upgrading a 30 amp coach to a 50 amp coach can certainly be done but the total price required to do so may catch some owners off guard.

Why not just upgrade the RV to 50 amps? I did it on my TT. You can always adapt it to a 30 if that's all the is at the campsite. I added a new panel and used the old panel as a sub. I feed the old panel off a 30 amp breaker in the new panel using the old 30 amp cord. Then I removed the 20 amp A/C from the old panel and put it on a 20 amp breaker on the new panel. The most expensive part was the wire but if you watch Craigslist, you might find a RV extension cord that you can use if you cut the female end off of it. If you get the A/C off the 30 amp panel, that frees up a bunch of amps for other things. It solved any lack of amperage issues we had in the TT. I may do it again in the class A, but for now it's ok. I'm in the middle of other projects!!!!!

GordonThree wrote:
If using an extension cord, how would it be possible for the two different hots to come together? Are folks using a cheater cable and back feeding the panel somehow?

the hots Don't come together 'too risky', No back feeding
if you have a 30amp RV, the 20amp will be a separate circuit not connected to the RV panel and 30 amp input, a separate outlet to plug an appliance/item into, good for portable heaters etc..

if using an adapter box to feed a 50 amp RV

you have (2) different feeds going to (2) different hot legs

one leg in the RV will have 30amp available, the other leg will have 20amp available

That is not true 50 amp service, as others have pointed out. Furthermore, some 30 pedestals are protected by an additional breaker at the service entry panel. Mine were until I upgraded to all 50 amp pedestals. If that is the case, all you will do is trip that breaker and you won't be able to reset it. You will have to call the office and they will tell you "It is a thirty amp pedestal, designed to deliver up to thirty amps of service. Therefore, you need to disconnect one of those cords." Your trick won't work everywhere.