220V/30 Amp vs 220V/50 Amp

[icepick]

I have never in my life seen so many people that have no idea what there talking about. Ive been an electrical contractor for 40 plus years, and many opinions here are just down right BS. one guy said get a qualified electrician to take care of it. DO NOT trust what you read hear

[Cat320]

This is a very tricky and complex issue, where you could do serious damage to either the house, the RV, or both. I would not do anything without it being checked out by an electrician, who is familiar with RV electrical systems. Your basic household electrician will be no help.

[distaff]

Originally Posted by icepick

I have never in my life seen so many people that have no idea what there talking about. Ive been an electrical contractor for 40 plus years, and many opinions here are just down right BS. one guy said get a qualified electrician to take care of it. DO NOT trust what you read hear

I agree that there are some posts that are thin on actual information. The dryer cord was a good suggestion and not one I'd thought of. I've bought one and a box and receptacle to make the adapter. I'll order a 50 foot extension.

I did have my friend check the outlet and he reports 240 V from ground to neutral and 130 v from x to y, so he is getting an electrician to come and check how it is wired. If it were my home I'd do it myself, electricity isn't mysterious to me.

[Mudfrog]

Originally Posted by Cat320

This is a very tricky and complex issue, where you could do serious damage to either the house, the RV, or both. I would not do anything without it being checked out by an electrician, who is familiar with RV electrical systems. Your basic household electrician will be no help.

Yes, for some, electricity is a mystery and is tricky. What the OP is wanting to do is not tricky at all and is very easy for many of us to do. If you're in the first category, then by all means, get an electrician.

The amperage rating of the circuit is the only difference here. The plugs/receptacles are of different configurations (they won't plug into each other), otherwise the wiring is identical. Hots left and right, ground top and neutral bottom.

Yes, it would be wise to get an AC volt meter and double check the existing dryer receptacle to make sure this is the case. Each hot to ground or neutral should be approximately 110 volts. Voltage across the hots should be approximately 220. Once this is assured, then get sufficient wire size for the length of run, the proper male plug, the proper female plug. Wire these up and to be safe, use an ohmmeter to verify your wiring between male and female plug.

Only thing to remember is that the existing dryer circuit is only rated at 30 amps. The dryer receptacle's breaker will probably trip if you try to run everything in the motorhome at once..

I did have my friend check the outlet and he reports 240 V from ground to neutral

Bet he took his readings from the wrong terminals. Shouldn't have any voltage between ground and neutral.

[distaff]

Ordered a 50 foot cord off Amazon, made an adapter with a dryer cord ($15 at Coast Appliances), and a receptacle and box from Home Depot (another $15 or so). My old dog Cowboy in the background. He was supervising. I have continuity from the ground to the box, and from the pins on the plugs to the corresponding holes on the receptacle.

My friend (who falls into the first category) found out he had the breaker off, so re-did the test and the only issue is he is seeing 14V between the hots and the ground, he is seeing 125V between each hot and the neutral. Suspect a bad ground and he will have an electrician check it out.

I'll make sure I set the inverter to 30 AMPS input on shore power so we don't overload. Thanks everyone for your suggestions, even the ones I ignored!

[garbonz]

Originally Posted by distaff

Ordered a 50 foot cord off Amazon, made an adapter with a dryer cord ($15 at Coast Appliances), and a receptacle and box from Home Depot (another $15 or so). My old dog Cowboy in the background. He was supervising. I have continuity from the ground to the box, and from the pins on the plugs to the corresponding holes on the receptacle.

My friend (who falls into the first category) found out he had the breaker off, so re-did the test and the only issue is he is seeing 14V between the hots and the ground, he is seeing 125V between each hot and the neutral. Suspect a bad ground and he will have an electrician check it out.

I'll make sure I set the inverter to 30 AMPS input on shore power so we don't overload. Thanks everyone for your suggestions, even the ones I ignored!

Looks good, glad you were able to wade through information and mis information, get a couple of good ideas and get yer project done.

[wa8yxm]

Distaff.. In case you have yet to plug in.. That is exactly how I'd do it.

[distaff]

Penultimate post - my friend (who luckily lives UP hill from the Oroville dam) had an electrician check out the receptacle and it is wired correctly, he must have been reading it wrong.

Should be good to go. I'll check the adapter and the new 50ft cable for continuity before I plug in.

[Vicr]

I've been an electrician for over 34 and design, build and wire the most complicated electrical systems on the planet and I can tell you I read more crap on the electrical subjects than any other topic. If you are not an electrician or an electrical engineer than DON'T POST! There are those of us on these forums who know how to answer these posts correctly with answers that comply with the NEC and NFPA.
Thank you,
Vic Rutherford
IBEW Local 46
Seattle, WA

[nothermark]

At least two of us who post a lot of good information here are not EE's or members of one of the Unions. We just know wiring. The task at hand is drop dead simple for anyone who understands the system and magic to the rest.

I'll not say any electrician cannot figure it out but I think we have had posted examples of electricians wiring a 240 VAC split phase drop for a motor home wrong. That is why I do postings recommending using a meter to check before plugging in. It's a simple skill. There are enough electrical questions to make it reasonable to advise everyone to have a meter and learn how to check connections with it.

[distaff]

Vic, I do agree that a lot of bad stuff gets posted. I'm not either an electrician or an engineer, so I'm careful in my responses around electrical matters. Having said that I've become an expert on the 12v systems, particularly the cross over charging systems that these coaches use, and that expertise is VERY hard to come by.

The AC stuff is pretty standard, but the inverters add a layer of complexity not found in most household wiring.

I do note that you didn't say you needed to be a union member to post, just actually knowledgeable.

[jelag]

so that 4 wire plug, if wired by CODE will have (1) white wire, a neutral, (1) Green wire, a ground, (1) black wire, 120V AC Leg, (1) red wire, 120V AC Leg... In the plug pictured above... the top lug (round) is the ground wire (Green) the bottom wire is the neutral wire (white) and the two are the red and black respectively. Measuring from the Black or Red to Neutral will show 120 VAC on the volt meter, putting the meter across the Red and Black will show 240 VAC....

It create a 30 amp circuit... you would take a male plug, wire the Ground (green) wire to the top, round lug.... wire the White neutral to the bottom Lug and wire your Black wire to either the left or right wire connector... thus giving you 120 VAC and leaving the (4th) connector blank....

In some cases, electricians have used a 4 lead wire with (1) green, (1) white, and either (2) black or (2) red... either case meets code and is acceptable.... but your cord will have just (3) wires and would be wired as I've suggested above...

I've personally seen lots and lots of outlets over the years wired by people who have no clue... but once they wire the plug (female) incorrectly they also wire the plug to the appliance (male) incorrectly and it all works.... the key here is to take a volt meter BEFORE you make up your cord and verify that the female plug in the wall is wired correctly.....

IF the circuit breaker is a twin pull 30 amp breaker.... you will end up with a 120 VAC cord with the capacity of 30 amps... if the breaker in the panel is a 50 amp twin breaker you will have a 50 amp single circuit.... and you could overload the electrical cord with many items in the unit running at one time....

I hope this clears the air of how this is done.... this is a very simple task with the understanding of how this works... hopefully I've given you the knowledge to do this without mishaps...

[twinboat]

Originally Posted by jelag

so that 4 wire plug, if wired by CODE will have (1) white wire, a neutral, (1) Green wire, a ground, (1) black wire, 120V AC Leg, (1) red wire, 120V AC Leg... In the plug pictured above... the top lug (round) is the ground wire (Green) the bottom wire is the neutral wire (white) and the two are the red and black respectively. Measuring from the Black or Red to Neutral will show 120 VAC on the volt meter, putting the meter across the Red and Black will show 240 VAC....

It create a 30 amp circuit... you would take a male plug, wire the Ground (green) wire to the top, round lug.... wire the White neutral to the bottom Lug and wire your Black wire to either the left or right wire connector... thus giving you 120 VAC and leaving the (4th) connector blank....

In some cases, electricians have used a 4 lead wire with (1) green, (1) white, and either (2) black or (2) red... either case meets code and is acceptable.... but your cord will have just (3) wires and would be wired as I've suggested above...

I've personally seen lots and lots of outlets over the years wired by people who have no clue... but once they wire the plug (female) incorrectly they also wire the plug to the appliance (male) incorrectly and it all works.... the key here is to take a volt meter BEFORE you make up your cord and verify that the female plug in the wall is wired correctly.....

IF the circuit breaker is a twin pull 30 amp breaker.... you will end up with a 120 VAC cord with the capacity of 30 amps... if the breaker in the panel is a 50 amp twin breaker you will have a 50 amp single circuit.... and you could overload the electrical cord with many items in the unit running at one time....

I hope this clears the air of how this is done.... this is a very simple task with the understanding of how this works... hopefully I've given you the knowledge to do this without mishaps...

The OP is looking for a 30 amp 240 volt service to use on a 50 amp 240 volt RV.

Your discribing a 30 amp 120 volt service, not what he wants.

You haven't cleared the air.

[Cat320]

Just remember, everything you get on any forum is worth exactly what you are paying for it.