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tbbronson · 05-04-2014, 10:02 AM

Hey Ya'll.... searched the threads & posts & don't see anything on my issue...thought maybe someone out there mite be familiar with what I'm trying to do. Since I have a 4-pin, 50 amp male plug on the Georgetown Class A Coach, and a 30 amp, 3-pin, female receptacle from the house (mtd. on post by previous homeowner), I thought it'd be easy to take the 25 ft. long 10/3 cord I had, that already had a 30 amp, 3-pin male plug on 1 end, and simply install a 50 amp female receptacle plug on the other end, to plug the Coach Male plug into. Only wanted the 120 v. for lite duty...running the Coach-Mtd. Battery Charger or maybe a small dehumidifier...wasn't gonna 'tax' the system with Hi-Amperage. So I did, realizing that there were only 3 wires to work with, I left the 4th. terminal conn. blank. ( I hooked the white to one side, black to the other, and of course, the ground to the bottom green ground terminal)....BUT...it doesn't work satisfactorily... only have partial voltage in the Coach...Microwave & A/C's won't power up at all. Some 120 v. receptacles work ???
Fire up the Generator, plug into it, and all is fine.... Pls. don't tell me I hafta' have a 4th. wire to make this system work !?! After-all... I know U can adapt easily in the C.G.'s from 30 A. up to 50 A. with those simple plug-in adapters....realizing that then a 30 A. system's being powered from a 50 A. one, opposite of what I'm tryin' 2 do....
Thanx & appreciate any input, as I would sure like to use this nice 3-wire cord I have....
A frustrated "neophite" electrician

Cooperhawk · 05-04-2014, 10:08 AM

50 amp four pin plugs have two separate 110 volt wires, one neutral, and one ground. What that does is give you two separate 110 circuits in your coach. What you are doing is not supplying power to one of the circuits.

RickO · 05-04-2014, 10:09 AM

Hi and welcome to the forum.

Are you sure the 30 amp outlet you have on the post is wired for an RV?

Typical household 30 amp receptacles I believe are wired differently than RV hookups. I believe most are wired to bring 240 volts to the outlet. Have you used a volt meter to measure the voltages you're actually seeing?

Rick

lanerd · 05-04-2014, 10:15 AM

Quote:

Originally Posted by RickO

Hi and welcome to the forum.

Are you sure the 30 amp outlet you have on the post is wired for an RV?

Typical household 30 amp receptacles I believe are wired differently than RV hookups. I believe most are wired to bring 240 volts to the outlet. Have you used a volt meter to measure the voltages you're actually seeing?

Rick

No... 30 amp rv outlet socket is one hot (120v), one neutral, and one ground.

What the OP needs is an 50 to 30 amp adapter.

http://www.walmart.com/ip/Prime-Wire...andle/22025553

It is wired internally to split the 120 v single line from the 30 amp plug to two 120v lines for the 50 amp cord. That allows both legs of 120v in the coach to have power.

Hope this helps

Ron

Skip426 · 05-04-2014, 10:16 AM

So basically what your doing is building your own 30 to 50 amp adaptor in the form of a power cord instead of buying one .
Your 50 amp coach requires 2 hot leads for the system to operate as designed, and a factory adaptor would split the 30 amp between the two, pins on your coach plug to accomplish that.
I have ; somewhere the testing for the plugs and I'll track it down and post it for you.
And as always , I see a bunch of other members type faster than I do.

BFlinn181 · 05-04-2014, 10:22 AM

By ignoring the 4th wire, you are only capable of getting one 'leg' of the power to your rig. Since your RV is wired for 50 amp service, about half of your circuits won't be connected. If you used a 'store bought' dogleg, you would be getting power to both circuits. If you'd used the 3 wire cord to connect to a 30/50 dogleg inside your electric compartment, you would be fine. Now you'll need to repair the cord and still buy the dogleg adaptor.

Brockx · 05-04-2014, 10:22 AM

You can buy variations of these at CW, Amazon, etc..

Prime RV Adapter, 30 Amp Plug and 50 Amp Connector With Indicator Light and Handle: Electrical : Walmart.com

Skip426 · 05-04-2014, 12:39 PM

Visit these sites for testing info.

Electrical Testing

http://www.myrv.us/electric/Pg/50amp_Service.htm

Give me a min. to test these links .
OK , only took two tries to get them right.

tbbronson · 05-04-2014, 02:36 PM

Gosh Guys.... Thanx so much.... never knew 'bout the dual 120V. circuits...but definitely makes sense...That's where my hang-up is.... I really appreciate the info., links, and response....
U've saved the day friends !!!!
Happy R.V'n....

wa8yxm · 05-05-2014, 09:00 AM

I have a 50 amp rig with two power cords.

One cord is a 50/50 (50 amp plug 50 amp marinco outlet)
the other is a 30/50 (TT-30 plug, 50 amp Marinco outlet) The two hot leads are bridged so everything works.

I also have a full set of pigtails so I can plug eitehr cord into either a 30 or 50 amp outlet (or a 15/20 amp outlet as well) and a "Cheater box" so i can use two 30 amp outlets.. when I have them.. Which is one place I park.

I do not recommend the cheater box.. But I do recommend dog bones to both (in your case) 30 and 15 amp.