Wiring 50A coach plug

Tikvah · February 16, 2014, 03:24:30 PM

Pictured below is my 50A plug that is being installed on the rear panel of my bus, basically above my drive wheels.

Anyway, what wire goes where? I should have two hot wires (probably never use one of them) and a neutral and a ground.

The receptacle is labeled:
"X" on the left in the picture, all alone (Purple)
"Y" top right (Black)
"G" Center right (green)
"W" Bottom right (white)

Also, need a refresher, I have a bare ground and an insulated neutral? or the other way around? I don't remember the terms for ground and neutral. I know, they're different, but they go the same place at the end of the day.

Second, when I'm on just 30A, what hot is being used, and what is left alone?
Thoughts?

Dave

stegey · February 16, 2014, 03:48:18 PM

I believe if you look at the bottom letter should be a W that would be the neutra.l the G would be the ground. and the X in the Y should be the two hot leads

Tikvah · February 16, 2014, 03:50:49 PM

I just modified my post. Yes, "W" not "Y". Thanks

Okay, what is ground, what is neutral? and, which is bare and which is insulated?

Ace · February 16, 2014, 04:16:40 PM

X & Y are interchangeable , red and black wires are hot (live) wires , one wire on the X, and the other on the Y. The neutral (white) and the bare ground wire MUST be on there designated connection.

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Timkar · February 16, 2014, 04:18:55 PM

bare ground (green) and an insulated neutral (white)

brmax · February 16, 2014, 04:51:20 PM

Both hots will normaly be used or at the ready, as a 220 v appliance might be used. In a lot of boxes an even draw of amps is a liking, so both hots are split on the loads. If only thirty is available some means of connection adapter might be needed?

belfert · February 16, 2014, 05:39:06 PM

A 30 amp to 50 amp converter will typically power both hot leads on the 50 amp side. Some have wired their entire bus to use just one hot lead on a 50 amp connection.

Tikvah · February 16, 2014, 05:42:38 PM

I'm thinking I might connect the two sides of my box through a knife-switch for when I'm on 110 volt supply, and open the switch when I'm on 220 volt supply. Does that seem to be the right thing to do?

My whole bus is wired for nothing but 110, but 220 would give me both sides of my box.

Lin · February 16, 2014, 05:56:47 PM

How do you plan to wire your breaker box? If you are wiring it for 240v, you will have the two hot wires going to different lugs on the panel, each one energizing one side. Therefore, when plugged in to 240v, everything works. The 30A to 50A adaptors you would have to use energize both of your 50A wires, so you do not need to make any special system for it. However, instead of having two 50A legs creating 120v and 240v, you then have 30A split between two legs of 120v only. This would mean that your 120v equipment works, but any 240 stuff won't.

There is an alternative whereby you use only one of the 50A wires and have some way of jumping it to cover both legs. You would then have 50A at 120v split between both legs. I have done this on my last bus, and my present one came that way too. We do not have any 240 appliances so it works fine for us. One benefit of this is that your shore cable is 25% lighter. Obviously, this is no good if you have an electric stove, or expect to be running more than 50A worth of equipment at a given time. Three AC's would be almost there.

brmax · February 16, 2014, 06:04:24 PM

Do most rv campgrounds have 50 amp now?, I dont have a clue I just remember ages ago they had 30s and with that they are always 2 hots so capable of 220v to power both legs of a electric box.
good evening to you all

TomC · February 16, 2014, 06:11:10 PM

I have my bus wired straight 120vac. Hence, I only use one side of the 50amp plug, for 50amps at 120vac which is enough to run 2 A/C's with power left over. Then with the generator, don't have to worry about balancing the loads from side to side. Good Luck, TomC

gumpy · February 16, 2014, 07:30:15 PM

As indicated already, if you use a commercial dogbone (dogleg??) adapter to connect you 50 amp 240v connection to a 30 amp 120v outlet, the adapter will cross the hot wire to both 240v hots in your cord, so both sides of your breaker box will be hot, but on the same phase. Most buses don't have 240v appliances, so this is typically not a problem. However, as also pointed out, you will have only 30 amps available, period, which is now split between both legs of the panel, and shared by every circuit.

There are some issues with this if you use an inverter and want to power both sides of the breaker box when on battery power. Many avoid this by only using one side of the 50 amp line. Others, like myself, find more creative ways to get around it.

Lin · February 16, 2014, 08:44:22 PM

Craig- A little hijack here-- I would be interested in your creative solution to the inverter issue since I have been known to forget to turn the water heater off before switching to the inverter. I have considered using a sub-panel, but have been managing with putting reminder markers on the switches. Sorry

oldmansax · February 17, 2014, 05:29:30 AM

Quote from: Tikvah on February 16, 2014, 05:42:38 PM
I'm thinking I might connect the two sides of my box through a knife-switch for when I'm on 110 volt supply, and open the switch when I'm on 220 volt supply. Does that seem to be the right thing to do?

NO! NO! NO! Don't do it! All it will take is one forgetful moment & a 50 amp site & both you & your bus can be toast!!

First, decide: How many amps does you bus need? If you only need 30 amps for now & future use, Just wire for 30. If you think you may need a 50 amp service later, wire for 50. Then, buy the 30 to 50 converter from WalMart!!!! It's only about $30. That will safely connect both legs of your 50A service when you only have 30A available; AND you can't forget & screw that up!!!

As an aside, I have learned to carry 50 to 30, 30 t0 20, 30 to 50, and 30A & 50A extension cables. That way I can connect to whatever. I just have to limit my usage to whatever is available.

BE SAFE!!!

TOM

oldmansax · February 17, 2014, 05:36:12 AM

Quote from: Lin on February 16, 2014, 08:44:22 PM
Craig- A little hijack here-- I would be interested in your creative solution to the inverter issue since I have been known to forget to turn the water heater off before switching to the inverter. I have considered using a sub-panel, but have been managing with putting reminder markers on the switches. Sorry

Lin, on the advice of others I used a sub panel on my old MCI. The main feed from the transfer switch feed the main 100A panel. I used that size panel so I would have enough breaker spaces. Everything that had to be fed BEFORE the inverter went to this panel. The inverter is also fed from this panel. Then, this inverter feeds the sub panel. All inverter loads are fed from the sub panel. Simple & effective.

TOM