Using 30A and 50A service simultaneously: a terrible idea?

[markaeric]

Hello all,

This is my first post, and I'm new to RVing. I've been doing my research on RV living as I plan on living in one for at least 6 months while I attend a school out of state.

I recently picked up a 1994 Damon Intruder in decent overall shape for a song and I'm slowly getting my ducks in a row for the big move. Since I'll be in Wichita, KS during the winter, one of my biggest concerns is keeping everything nice and toasty. From what I gather, the efficiency of these built-in propane furnaces leave a lot to be desired. To add to that, the propane tank is not removable, and I really don't want to have to go through the hassle of driving it to a gas station every time I need more. Therefore, I'm adding electric heating elements to the furnace, as well as an on-demand type electric water heater.

Currently, the motorhome only has 30A service which just won't cut it, so at the very least I need to modify it to 50A @ 220V. This isn't a big deal, but my power budget is just about taken up if the furnace and water heater are run simultaneously. Yes, I can turn off the furnace when I need to run the hot water, and that's probably what I'll end up doing, but then I had an idea...

I could keep my 30A service just the way it is, and use a separate 50A service just for the furnace and water heater. As long as the park has both services, *technically* I can hook it up. My concern is whether or not park outlets with both services can actually handle the combined power requirement (so, the wiring to the meter).

I've been searching around to see if anyone considered/did something similar, but came up empty handed. Does anyone here have any thoughts on this? Is this a terrible idea? Any input would be appreciated.

Cheers,
Mark

[Fred1609]

Cant answer your questions, but can suggest that parks only have a 30 or 50 amp post. Some have a outlet for 15 amp, but I haven't seen a site which had two power outlets.

[NeilV]

Usually the 50 amp is not 220V at a park. Most would be inclined to get an extend-a-stay attachment to use an external propane tank.

[Bigd9]

Most parks the 50 amp service is 120 volts. That being said you could possible use a heavy duty extension cord to the post and either plug it into a 20 amp plug on the post or use a 50 amp to 20 amp converter. That is what we used to do when we winter camp in a 30 amp rig. I then plugged the electric heater and plumbing heat tape into the 20 amp extension cord and ran the rest of the coach off the 30 amp service.

Be very careful with portable electric heaters and moisture problems while winter camping. Make sure the portable electric heater has a safety feature that shuts off if it should be knocked over. Especially important if you have any pets that could knock it over.

You will need to control moisture inside the camper by either opening a vent especially when showering, or use a dehumidifier.

Oh yes, one more thing:

[ronspradley]

I converted my MH to 50 amp and I run two electric space heaters when needed during cold weather. One in front living room and one in rear bedroom. These supplement my propane furnace, if I need more heat or need to keep holding tank area from freezing. I use propane for water heating, just turn on when needed. I do not keep MH in a place as cold as where you will be. You could keep your 30 amp and just run a separate heavy extension cord to power pedestal for the needed 15/20 amp for the second space heater. And plumb the line for using a separate propane tank to keep outside so you do not have to move RV for more propane. Best of luck and keep warm. ☺

ronspradley

.

[chawkins99]

Originally Posted by Fred1609

Cant answer your questions, but can suggest that parks only have a 30 or 50 amp post. Some have a outlet for 15 amp, but I haven't seen a site which had two power outlets.

Most sites I have been on have 15/20A, 30A and 50A outlets on the same pedestal.

Originally Posted by NeilV

Usually the 50 amp is not 220V at a park. Most would be inclined to get an extend-a-stay attachment to use an external propane tank.

The 50A circuit is actually 2 x 120V @ 50A but if you measure across the 2 hot wires, you will see 240V.
Nothing in an RV should require 240V. All devices connect to one side or other for 120V.

Back to the OPs question, the 30A outlet is most likely connected to one side of the 50A outlet so if you are plugged into both 50 & 30A, you are potentially drawing 80A from the one circuit and I seriously doubt that the wiring is rated for 80A continuous.

[Steve Ownby]

Actually most commercial RV park pedestals are wired with both a 30 amp 120 VAC receptacle and a 50 amp 240/120 VAC receptacle. There will most likely also be a GCFI 20 amp receptacle. If it is wired correctly there will be the capability of 240 VAC at the pedestal and you can use it as you desire. Again, if the park wiring is up to snuff, there should be enough capacity there for you to use both.


Steve Ownby
Full time since '07

[markaeric]

Thanks for all the prompt replies!

@Fred

I have 0 experience with parks, so I wouldn't know first hand
However, I have seen pictures online where all three standard outlet types are provided. That said, I have no idea how (un)common they are.


@NeilV

I was under the impression that the 50A outlets are two 110V legs, 180 degrees out of phase with each other making it 220. I can't find information stating otherwise.

I have been considering the Extend-A-Stay attachment, at the very least for the stove. I'd just hate to use the propane furnace in the dead of winter and seeing 20% or more of the heat being wasted right out the exhaust end of the furnace. I'm on a very tight budget, so any savings helps.


@Bigd

Now this is the 2nd response stating that 50A service is 110V. I'm curious about this (see above). I did e-mail the park operator of where I'm planning on staying, and he did confirm that it's 220V.

In a way, you did what I was thinking of doing, but instead of using 30A + 20A like you did, I'll be using 50A + 30A (which is substantially more, so hence my concern).

Thanks for the tips regarding the space heaters. I don't actually intend on using any (instead, my furnace is modified to support both electric, and propane operation).

Why is moisture any more of a problem than it would be in a house? And as far as I know, most homes require a humidifier during the winter in cold areas due to how dry it is outside.


@ronspradley

That makes you the second one mentioning using 30+20. So how bad would 50+20/30 be? Well at this point I'll definitely need to go with 50A 220V at the very least because that's what my furnace and water heater will require.


@all
Thanks for the replies and warm welcome

[markaeric]

@chawkins

"Back to the OPs question, the 30A outlet is most likely connected to one side of the 50A outlet so if you are plugged into both 50 & 30A, you are potentially drawing 80A from the one circuit and I seriously doubt that the wiring is rated for 80A continuous."

This is my concern. They should have individual breakers for each outlet, but is the wiring to those capable of providing 80A on one of the 120V legs?.. That's my concern.


@Steve Ownby

Thanks for your input. I couldn't comment on the wiring at this particular park, but I've seen pictures of pedestals getting installed and they're feeding them with some seriously thick conductors (~1/2"). I'm guessing there are some state/federal requirements on how these things are wired up. If each outlet has it's own breaker, and those aren't fed to some other main breaker on the pedestal, then one would hope the wiring to the pedestal is rated to support all the outlets combined.

[OB-One]

The "50-amp" service is actually two 50-amp 120VAC circuits. This provides a total of 100-amps at 120VAC, (50-amps per circuit). This can also be correctly stated as being a 50-amp 220/240VAC circuit which means that it can supply 50-amps at 220/240VAC or two circuits of 50-amps at 120VAC.

Whether you can use the "30-amp" service and the "50-amp" service on the same pedestal simultaneously will depend upon the specific pedestal and the supply wiring to the pedestal. Most pedestals are not designed to supply the "30-amp" and "50-amp" services simultaneously. A "50-amp" service requires a minimum internal and supply wire size of #6AWG.

Your requested use "could" pull 80-amps on one of the two 120VAC circuits that supply the pedestal. This would require a minimum supply wire size of #3AWG. It's unlikely that the supply wire to the pedestal is this large.

[CampDaven]

If you are going to winter in real cold and snow, 50A will be nuff, but you will need a ton of propane plus space heaters plus a way to keep your water and sewer flowing. The electric and propane bills may scare you! I know some folks that tried real hard to make it work and gave up after frozen pipes and other painful experiences.
Best wishes!

[wildtoad]

How much hot water do you need? Instead of installing a 220v on demand wh have you given thought to adding an electric element to your existing wh? They sell them at Camping World and are called Hott Rod. They draw very little power and will get the water very hot. If we really need a lot of hot water we will turn on both the electric and the propane only for the time we plan to use the hw, then turn the propane off.


In regards to space heaters, I'd simply run one heater off the normal house 30 amp, and then run a extension cord to the 15/20 amp plug at the box to run a second one.


One question I have that I have not seen others ask, is what are you planning on doing about your water lines, holding tanks?

[Bigd9]

Originally Posted by markaeric

Why is moisture any more of a problem than it would be in a house? And as far as I know, most homes require a humidifier during the winter in cold areas due to how dry it is outside.

A RV is much smaller than a home and when moisture is generated by dish washing, showers and just breathing, a lot of water gets put into the air. There isn't a whole lot of dry outside air getting in or moist inside air getting out so the moisture has nowhere to go. When its gets cold outside you will see condensation on windows and this could be enough to run down the walls below damaging them. I tried telling my wife to stop talking so much because she was dumping way too much moisture in the air, but for some reason she didn't listen to me.

In my old Fleetwood Discovery Diesel coach, we camped in West Virginia at a ski area once and it got down to -5 degrees. When we woke up the next morning you could see every aluminum wall stud because the moisture in the air froze to the walls right where the studs were. The aluminum was conducting the heat to the outside and they ended up being below freezing. We were nice and warm and toasty but the walls right where the studs were sure weren't. It looked like vertical lines of white snow on the walls! Really way cool!

I'll have to check the inside humidity this year when we go skiing. I've never done that and you have given me an idea.

One more piece of unsolicited advice, make sure you have a escape plan incase the worse were to happen. If you lost heat where would you go? What would you take with you? How long can you stay there?

Best of luck, and I hope school goes well.

[markaeric]

@CampDaven

I'm trying to avoid propane like the plague. It's just a hassle, and at current prices would likely be more expensive than staying strictly electric. The poor efficiency of these propane furnaces just makes it that much worse. The heating element I installed in the furnace is 4500W which is the equivalent of 3 typical space heaters. I may use an actual space heater on those really cold days if necessary, and perhaps put it in the bedroom at night and turn down the thermostat on the furnace.


@wildtoad

I considered adding an electric element to the current water heater, but I figured since I primarily need it for daily showers and to a lesser amount, sinks, it would be more efficient to go on-demand. Plus, it's just nice having as much hot water as I want.

As for the water lines and holding tanks, the holding tanks have heating pads underneath them. The drain hookups and tanks are enclosed in one of the storage bays, so I'm not sure I need to be too concerned about them freezing. If necessary, I could throw a 60-100W incandescent lamp in there for some extra heat, or perhaps a mini oil-type space heater. I also intend to install skirting around the motorhome to prevent wind from blowing underneath. As far as water lines, since they're all internal and I won't be filling the tank, I don't think (correct me if I'm wrong) I need to do anything special about them other than heat taping the outside hose.