Hi, I don't know if this is the right place to post this, but if there are any electricians out there, I have a question for you. I am aware of the difference between the 220v dryer type plug, and the 50amp RV plugs, which are really 2x50 amp 110v (poor explanation I know) and that you cannot plug the rv cord into the 220v plug without doing severe damage.Anyway, my question is this. Is there a way to make a short "extension" type cord that could be plugged in to the 220 v plug in the garage (or whereever)on one end and then convert that plug (maybe with some kind of converter or?)on the other end to the correct 50 amp power source (plug) which we could use to plug in our rv cord? Instead of having to re-wire the existing plug to an RV plug, (since we would want to do this at the homes of several friends and relatives who have these plugins for their welders, etc). I hope this explanation makes sense.Thanks

ktmrfs wrote:wa8yxm wrote:Ok, I will answer, Dryer outlets come in two flavors and one of them can be wired two different ways.The two flavors are 3 and 4 wireNow if it's a 3 wire the answer on converting ins likely NO, you will really need to pull new 4-wire feed line to do it properly and safely.If it's a 4 wire then you need to look at the wires.There are 4 wires, One white, and either a black and a red, or two blacks, and a bare or green.Forget the bare/green for the momnent.Are the black, red and white wires ALL THE SAME SIZE.If so, then you can convert.yes, the 110/220V appliance wiring is a real can o worms!!A wide variety of NEC code changes over the years has really made it a quagmire IMHO. The "3 wire" dryer plug systems still have two 120V legs and a neutral, just like 3 wire ovens and stoves of the same era. The motor and controls run off one leg at 120V. The heating element across the two legs for 240V. There is also a neutral/"ground", but in "days of old" around WWII, NEC allowed neutral and ground to be tied together at the appliance plug. Ergo, no seperate ground available, and therfore no seperate ground back to the panel. (Or that's what the folklore is anyway) Was comon and per NEC code at least through the 80's in the US for dryers, ovens, stoves etc.So, a 3 wire may or may not be adaptable. Is it really a 3 wire or a 4 wire? with ground in the box, but not at the outlet. One BIG issue is that as you point out, the neutral in these old 3 wire systems (and some 4 wire as well)neutral was often NOT the same guage, it was smaller. The heater element, which was the 30, or 50A draw is across the two hot legs, so no current flows in the neutral from that load. The motor and control circuit doesn't draw near as much current, so in these old systems any neutral or ground wire was often a smaller guage.I think it was sometime in the late 80s' early 90's that NEC code changed and now requires a 4 wire system (two hot legs, neutral and ground) for dryers, ovens, stoves for new construction or remodel. You'll have 240V across the two hot legs, 120v from either leg to neutral, and a ground. Same as the configuration of a 50A RV. But for an RV the neutral must be the same size wire as either hot leg. RV's have lots of 120V stuff and often little or no 240V stuff, so current flow is from each 120V hot leg to the load and back through the neutral to the panel. depending on the load balance in the trailer between the two hot legs, you could end up with anywhere from 0 to 50A in the neutral leg. And to add to the mess, often the 3 wire setup was aluminum wire, which requires special recepticals that are rated for connection to aluminum wire. Don't know if Aluminum is still common or allowed on the 4 wire dryer, oven, stove or not. But if that's what you have on a 4 wire system, make sure you use the proper receptical. When we remodeled and I switched the dryer, stove, oven to 4 wire copper. so.... IMHO unless you really know wiring, best left to an electrician.Good advice and reading. Don't let just any electrician work on your trailer I've heard some bad stories. Rvs are a little different. Sometimes there not use to them.

enblethen wrote:In the US and some parts of Canada, the elctrical code changed dryers and range receptacles to four wire. Both dryers and range circuits after about 1988 has four wires.Look closely at the receptacle for number of openings. It should have four on later installations.It is not only look at but must be tested for proper wiring.You should not attempt to make an adapter. The receptacle must have a neutral and a groundAgreed, and that's how my dryer receptacle was wired (luckily 4 wire) I pulled the hot, neutral, and ground off of it to wire my 30A RV outlet on the other side of the wall, opposite the dryer receptacle. We didn't have an electric dryer so the receptacle was not being used.

A properly wired 4-wire 240 volt plug is what you need- the only reason you cannot use a dryer type is they don't have a neutral, and use 3 wires (and look too much like the 30 amp 120 volt RV plug).. If the 50 amp RV plug fits, it will be fine, as long as the outlet is properly wired.

Welder receptacles don't normally have the white neutral wire, Art.As Chris says, I type much slower.

convert 220 v plug to 50amp rv plug | Good Sam Community

enblethen
Nomad
Dec 03, 2013
In the US and some parts of Canada, the elctrical code changed dryers and range receptacles to four wire. Both dryers and range circuits after about 1988 has four wires.
Look closely at the receptacle for number of openings. It should have four on later installations.
It is not only look at but must be tested for proper wiring.
You should not attempt to make an adapter. The receptacle must have a neutral and a ground
kaydeejay
Explorer
Dec 03, 2013
Robin'n'Marian wrote:

Is there a way to make a short "extension" type cord that could be plugged in to the 220 v plug in the garage (or whereever)on one end and then convert that plug (maybe with some kind of converter or?)on the other end to the correct 50 amp power source (plug) which we could use to plug in our rv cord? Instead of having to re-wire the existing plug to an RV plug, (since we would want to do this at the homes of several friends and relatives who have these plugins for their welders, etc).
I hope this explanation makes sense.
Thanks
If the outlet is a 4-prong 220V stove/dryer one, then you can plug right in as it has the split 220V (2 x 110V) that you need.
If the outlets are the 3-prong welder type then there is no way to plug your RV in there as there is only 220V available.
As a previous poster said, such an outlet does not have the neutral you need to correctly power your RV. No converter/adapter cord is going to solve that problem.
westend
Explorer
Dec 03, 2013
That's it, I'm going to start with this thread since it is barely sensible because of the use of "plug".

The device that is used to connect a male cord plug to power is called a "receptacle", or sometimes, an "outlet". It is not a "plug". A "plug" describes a male connector, usually at the end of a cord.

\Rant over

Your best choice for connecting your 50 amp RV power cord to a host's house is to use a 50 amp--> 20 amp adaptor. You would then have a GFCI protected circuit and will not have the added liability of any miswiring or insufficient protection from an unknown circuit in the host's house.
96Bounder30E
Explorer II
Dec 03, 2013
Moved from General RVing
Rvpapa
Explorer
Dec 03, 2013
Welder receptacles don't normally have the white neutral wire,
Art.

As Chris says, I type much slower.
Chris_Bryant
Explorer II
Dec 03, 2013
A properly wired 4-wire 240 volt plug is what you need- the only reason you cannot use a dryer type is they don't have a neutral, and use 3 wires (and look too much like the 30 amp 120 volt RV plug).. If the 50 amp RV plug fits, it will be fine, as long as the outlet is properly wired.

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