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IC2 · 11-11-2021, 06:46 AM

Thinking of jumping into the Class C world after years of 5th wheels. We have just barely scratched the surface so far with our look but one item does concern me and that's that most Class C are 30 amp service or about 3600 watts vs the approx 12,000 for 50 amp service. An a/c, hot water heater along with a 900-1200 watt microwave will eat up those amps in a hurry. Not interested in a second or sub panel

OK, having said that, any C will be used, not new but no older then 2014/5

Has anyone done a full 50 amp conversion to include new wiring to a new panel? What problems will I be looking at besides the cost? On our current 5er, I see three #6 AWG wires along with a #8 for ground. A distribution panel with a lineup of 120VAC breakers and a line up of 15/20 amp fuses for 12VDC. Any existing 30 amp dist. panel would probably need replacing I don't think the converter cares but regardless, not a problem. An inverter probably doesn't care either. It would also need a new power pigtail (I already have a spare).

Am I missing something vital or it really that simple?

MrMark52 · 11-11-2021, 06:59 AM

I think your headed down the right road - just know that a 50 amp service is 2 legs of 120 volts, not 1.
Had friends who bought a C that the PO added a 2nd roof AC. The coach had 2 tethers - a real pain in the kiester as far as I was concerned - not to forget that without upgrading the genset, they could only run 1 AC unit while on the road. But then 2 tethers insured they didn’t try to run both AC units at the same time.

BCam · 11-11-2021, 07:01 AM

I haven't done it but I've researched it. The biggest challenge seems to be replacing the feed to your panel with 6 AWG wiring. If you're lucky, your Automatic Transfer Switch may be already rated for 50A. Here are a couple of links for you (the video is part 1 of 4):

https://www.youtube.com/watch?v=iFYapUdEUMc

https://www.winnieowners.com/forums/...ml#post3842611 (There are additional links in post #2)

IC2 · 11-11-2021, 07:09 AM

Quote:

Originally Posted by MrMark52

I think your headed down the right road - just know that a 50 amp service is 2 legs of 120 volts, not 1.
Had friends who bought a C that the PO added a 2nd roof AC. The coach had 2 tethers - a real pain in the kiester as far as I was concerned - not to forget that without upgrading the genset, they could only run 1 AC unit while on the road. But then 2 tethers insured they didn’t try to run both AC units at the same time.

Yep, I'm aware that RVs have 2 separate 120VAC legs. As far as a genset, most seem to be in the 4KW range and will only run one a/c (I think 2@11K a/c's will operate though if an RV has a management system)

Quote:

Originally Posted by BCam

I haven't done it but I've researched it. The biggest challenge seems to be replacing the feed to your panel with 6 AWG wiring. If you're lucky, your Automatic Transfer Switch may be already rated for 50A. Here are a couple of links for you (the video is part 1 of 4):

https://www.youtube.com/watch?v=iFYapUdEUMc

https://www.winnieowners.com/forums/...ml#post3842611 (There are additional links in post #2)

Thanks for the links. That transfer system is so far a 'black box' that I'm aware of but have no history with - yet

MrMark52 · 11-11-2021, 07:25 AM

Quote:

Originally Posted by IC2

Yep, I'm aware that RVs have 2 separate 120VAC legs. As far as a genset, most seem to be in the 4KW range and will only run one a/c (I think 2@11K a/c's will operate though if an RV has a management system)

Our ‘02 “A” has 2 roof AC’s and runs both AC’s at the same time, no management system. 5.5kW genset, dual 11k BtuH units.
Per the Dometic manual for the AC units - cooling consumption is 1350 watts/unit. Minimum kW genset for a single unit is 2.5 kW, dual units is 5 kW.

**Lt Dan** · 11-11-2021, 07:29 AM

I have done what you are asking about to our 2006 Itasca. It originally was a 30 amp coach and I converted it to 50 amp. As noted, the hardest part of the conversion was running new wire from the transfer switch to the breaker panel. You will need #6 cable for that run. The only other things you will have to do is see if transfer switch is 50amp 240volt compatible and if your breaker panel can be separated into the two 120v legs. If not, then it will require changing both of those out. I was lucky with our Itasca in that it already had a 50 amp transfer switch that just required a little rewiring and the breaker panel was easily split.

Depending on the generator, you probably won't get a true 240v feed but two separate 120v feeds. That can still be split to the two legs in the breaker you just won't have 240v across the two.

Here's a couple of photos of the breaker panel before and after and one of the ATS after conversion.

IC2 · 11-11-2021, 08:00 AM

All great information and will be a part of any inspection of a coach.

DonaC · 11-11-2021, 01:00 PM

I guess that your math is OK, but unless all of your AC loads are changed to actually run on 240volts, you won't have effective load capacity of 12KW. In effect you will have two 25 amp 120 volt feeds. So 6KW capacity.

wolfe10 · 11-11-2021, 01:03 PM

Quote:

Originally Posted by DonaC

I guess that your math is OK, but unless all of your AC loads are changed to actually run on 240volts, you won't have effective load capacity of 12KW. In effect you will have two 25 amp 120 volt feeds. So 6KW capacity.

Totally INCORRECT.

50 amp RV service is TWO 50 amp hots. Look at any CG 50 amp outlet. You will find two 50 amp breakers (not 25 amp) pinned together.

DonaC · 11-11-2021, 01:27 PM

I'll admit to not having studied this in depth, not being a residential electrician. But in a 240 volt system, aren't those two breakers part of one series circuit? 50 amps in and 50 amps out is still 50 amps isn't it?

wolfe10 · 11-11-2021, 01:37 PM

Quote:

Originally Posted by DonaC

I'll admit to not having studied this in depth, not being a residential electrician. But in a 240 volt system, aren't those two breakers part of one series circuit? 50 amps in and 50 amps out is still 50 amps isn't it?

I wish I could put this is nicer words, but this is totally inaccurate.

Please post answers to things you ARE familiar with.

Otherwise others could get confused!

One of the CG 50 amp breakers is L1, the other 50 amp breaker is L2. 240 VAC between L1 and L2. 120 VAC between either L1 or L2 and the neutral. Same as most home electrical breaker boxes.

KanzKran · 11-11-2021, 01:39 PM

Quote:

Originally Posted by DonaC

I'll admit to not having studied this in depth, not being a residential electrician. But in a 240 volt system, aren't those two breakers part of one series circuit? 50 amps in and 50 amps out is still 50 amps isn't it?

Sort of, yes. But 50A in through L1 passes through 50A worth of 120V load on its way to the neutral buss, but then it passes through whatever load is on L2, from the neutral buss through the other 120V loads then out through L2. If both sets of loads, on L1 and L2, are not equal, then the difference in that current passes through the neutral conductor back to the transformer. Or from the transformer to the neutral. And of course, current changes direction on all legs (for a given set of loads) every 1/120 of a second on a 60Hz system.

So 50A in from the transformer on L1 drives a total of 50A of load on L1, then continues on past the neutral to drive 50A worth of load on L2, then back to the transformer. That's assuming 50A of load on both L1 and L2, and also assuming they're all 120V loads. If there are any 240V loads, current simply flows from L1, through the load(s), then back to the transformer through L2 (and reverses direction . . . ).

Current is additive on each leg L1 and L2, so some 120V loads on L1 plus some 240V loads on both L1 and L2 add to each leg.

And the neutral only carries the difference, which in the worst-case scenario is 50A (all loads are only on L1 or L2), but it's usually less as it's rare for either hot leg to be loaded to 50A with no load on the other leg.

Birdgoblue · 11-11-2021, 01:45 PM

6 guage is thick and stiff, I would recommend looking for stranded welding wire, it will a lot more flexible and worth the costs.

IC2 · 11-11-2021, 01:56 PM

Quote:

Originally Posted by Birdgoblue

6 guage is thick and stiff, I would recommend looking for stranded welding wire, it will a lot more flexible and worth the costs.

I used 6AWG solid strand when I installed the surge protector on our current 5er. It almost requires a hammer to make a bend. So, yes, it will be stranded vs nasty solid conductor wire (and, of course copper not aluminum)