220v water heater wiring question

HomeGrown · 07-18-2011, 09:36 PM

Hello all, I've got a question regarding a water heater conversion in my Gulfstream FEMA trailer. Since it will only be used in a full-hookup park, I'm doing a full electric conversion on it so I won't have to fool with propane. I'm going to be replacing the propane water heater with a 220v tankless unit that will draw a max of 38 amps.

I'm wondering if I can run a cable direct from the water heater to plug into the 50 amp service, or if I should install a 220v service box and run it through a 40 amp breaker. I'm inclined to go the dedicated cable route if since it will be the only item powered by the 50 amp service, although installing a service box may give me more options.

Thank you for any thoughts/input!

The_Stuff · 07-18-2011, 11:34 PM

hmm not sure if you get 220v out of a 50 amp service. can't remember how it works for sure. might want to ask an electrician.

LadyWindrider · 07-19-2011, 01:28 AM

50 amp service is NOT 220 volts. It is two 25 amp legs, but they are on the same phase, so no 220 volts. Understand not wanting to use propane, but you can get a 30 gallon water heater for 110 volt use. It will not tankless though. Since it is permanent, could put the water heater under the trailer, with a little plumbing.

**KyDan** · 07-19-2011, 06:35 AM

Quote:

Originally Posted by windrider

50 amp service is NOT 220 volts. It is two 25 amp legs, but they are on the same phase, so no 220 volts. Understand not wanting to use propane, but you can get a 30 gallon water heater for 110 volt use. It will not tankless though. Since it is permanent, could put the water heater under the trailer, with a little plumbing.

I don't think you are correct here.
I believe 50 amp RV service is TWO 50 amp 120 v legs and they ARE on
different phase so they can be combined into 240 when needed.

LadyWindrider · 07-19-2011, 08:58 AM

If that were the case, and you used a 50 amp to 30 amp adapter, (which would be only one leg of 220), and plugged the camper in to a 30 amp pedestal, then half of your trailer would be dead because one leg of the AC voltage would be missing.

jimh · 07-19-2011, 09:21 AM

the 50 amp service is 220. Ur neutral is too small to suport 2 110v circuit. The 50 a main is ganged.
U trailer uses it as two circuits with the neutral there to carry the imbalance.

I would run a seperate panel with a 50 main and put a 40a 220 breaker in there and run #8 between that 40 a nreaker anf ur new water heater.

HomeGrown · 07-19-2011, 09:27 AM

Yep, it's certainly 220, but my plan is to not change the 30 amp service it will remain as-is, just utilize the 50 amp service for the water heater only. I don't think I could run the 50 amp service exclusively, as there wouldn't be enough available current when the water heater is in use.

jimh · 07-19-2011, 09:35 AM

Quote:

Originally Posted by windrider

If that were the case, and you used a 50 amp to 30 amp adapter, (which would be only one leg of 220), and plugged the camper in to a 30 amp pedestal, then half of your trailer would be dead because one leg of the AC voltage would be missing.

The adapter supplies both legs of the 50a from a single 30a service so all circuits are live...just on the same phase.
My trailer has no 220 v appliances but it is available in my breaker box.
An easy way to varify that 50 a service is 220v is to check it at the pedistal with a volt meter.

The_Stuff · 07-19-2011, 09:56 AM

very true Jim. end the debate with a multi meter lol.

would been nice to have a 240v water heater in my unit. im dead sure its a GSW 110v unit. (lol dad calls them gun shot wounds)

LadyWindrider · 07-19-2011, 09:58 AM

Well, after some research, it appears the 50 amp plug is 220 volts. How it splits in the camper and other stuff to be determined. As for a 50 amp to 30 amp adapter, it can only supply one leg of service, as there aren't enough connections in the 30 amp service plug. Only three, one for hot, one for neutral, and one for ground. The 50 amp plug has extra connections for the extra leg.

HomeGrown · 07-19-2011, 12:23 PM

If I recall correctly, what I saw on the park hookup was (2) 25 amp breakers in tandem.... so if you split the legs, you'd only be getting 25 amps.
I wouldn't mind doing a single 50 amp service and split off a leg for the rest of the trailer, but I'm concerned about the current draw from the water heater not leaving enough available current for the rest of the trailer. Of course being an on-demand unit, it will only be drawing when there's a demand for hot water.

The_Stuff · 07-19-2011, 01:40 PM

thought the 50 was technically 2 30 amps?

HomeGrown · 07-19-2011, 06:17 PM

I'm a total n00b, but I'm pretty sure they are 2 25 amp legs.

jimh · 07-20-2011, 08:17 AM

i believe when u take a second look, u will find a twin 50 amp at the pedistel. there is over 3 times electrical power available at a 50 amp site (actually 3.33x) than at a 30amp site.

if u have a trailer with a 50amp service, u will find a twin 50 main in the breaker box.

**KyDan** · 07-20-2011, 08:37 AM

Quote:

Originally Posted by The_Stuff

thought the 50 was technically 2 30 amps?

and this one>> I'm a total n00b, but I'm pretty sure they are 2 25 amp legs.

NOT TRUE.

Please read here---
The 50-amp 120/240-volt 3 pole 4

Or just google
how to wire a 50 amp rv receptacle
and stop guessing!!!

HomeGrown · 07-20-2011, 10:25 AM

Quote:

Originally Posted by KyDan

Please read here---
The 50-amp 120/240-volt 3 pole 4

Or just google
how to wire a 50 amp rv receptacle
and stop guessing!!!

Bookmarked that link, thanks neighbor!

(I'm in Frankfort). Very good info there.

And I'm not by any means "guessing" when it comes to wiring up 240. I wasn't concerned with it at the time I plugged into the 30 amp service, only trying to recall what I thought I saw there.

BTW: I wouldn't advise ANYONE to simply Google something as potentially deadly as wiring up a 240v service, there's way too much bad advice on the web (much of which I've seen on ehow.com).

The_Stuff · 07-20-2011, 06:22 PM

bookmarked that to! good to know incase i put a 240v washer/dryer in.

HomeGrown · 07-20-2011, 06:42 PM

Quote:

Originally Posted by The_Stuff

bookmarked that to! good to know incase i put a 240v washer/dryer in.

Is that common to install 240v laundry service? I'm sure it would dry much faster than a 120v unit. I just picked up a Splendide washer/dryer unit that will require 120v @ 10 amps. I'm thinking if I run a 240v service I should have enough power to take the 10 amps from one of the legs.

The_Stuff · 07-20-2011, 10:06 PM

homegrown, the sear stacker/washer is 240v. id love the 110 splendide units but im quoted 1600/piece for them.. the sears stacker is 990$ lol

HomeGrown · 07-21-2011, 06:39 AM

I really lucked out when I got our Splendide combo unit. I was literally ready to order it on line for around $1200 (which was a good price), but decided to just take a quick look on Craigslist. Found a guy selling one with about 3 months use on it for $400. It was 10:00 at night and I normally don't call anyone that late, but decided to anyway. Turns out he was a night owl (his wife worked 2nd shift), so I drove an hour to Louisville and picked it up. Love the unit, it works great.

I think I will check into one of those filtered dryer vents to capture the otherwise wasted heat, as long as moisture isn't an issue.

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