The previous owners of our home installed a 8/3 wire from the breaker box to the garage. I assume they intended to install a welder or something, but never did. The wire terminates in the breaker box and is not hooked up to anything, and the wires are loose in the metal outlet box. I was hoping to install a 50 amp service, but realized I don't have a ground wire. I have a red, white and black wire only. My question is, can I use the red wire as my ground for a 30 amp service? I'm thinking I would connect my hot and neutral as usual to a 30 amp single pole, and the red to the ground buss bar in the breaker box. I found several people on here refer to www.myrv.us that has very good instructions about wiring a 30 amp service, but it doesn't address my question.

I don't think it matters which color you use as long you own your house and you never want to change anything. However, if you ever decide to sell the house that wiring configuration will most likely fail an inspection (but it will not hurt anything or cause any problems ... just inspectors). If you ever decide to sell, just unhook that wire and put it back the way it was.When we had our garage wired for 30 amp, I had an electrician actually hook the wires into the breaker panel and the outside plug box. He said, Black wire to the copper colored screw, white wire to the silver colored screw, and the third one to ground.

Back in the day, the NEC allowed for this but you need to use colored tape to identify the conductor (hot/neutral/grd). If it is no longer legal, I am sure someone will chime in.

A dangerous game for the next guy - if you do use the red, mark it with several bands of GREEN electrical tape at each end, or even pigtail with green or bare copper at each end so it's obvious.

RV ElectricYou can tape the ends of the red wire with green tape at both ends to make sure you and your successor will know years from now what is what. They sell rolls of colored tape for that purpose at HD or Lowes.

As the wiring was probably installed for a 220v circuit, A copper ground back to the box may not be required. The white wire is always a ground, and codes may just require an earth ground at the outlet. I thing your best bet would be to check with a local licensed electrician, but I personally would never use a red wire as a ground connection.

30 AMP home wiring Question | Good Sam Community

28 Replies

BoonHauler
Explorer
Feb 16, 2014
Dutch Oven Man wrote:
The previous owners of our home installed a 8/3 wire from the breaker box to the garage. I assume they intended to install a welder or something, but never did. The wire terminates in the breaker box and is not hooked up to anything, and the wires are loose in the metal outlet box.

I was hoping to install a 50 amp service, but realized I don't have a ground wire. I have a red, white and black wire only.

My question is, can I use the red wire as my ground for a 30 amp service? I'm thinking I would connect my hot and neutral as usual to a 30 amp single pole, and the red to the ground buss bar in the breaker box.

I found several people on here refer to www.myrv.us that has very good instructions about wiring a 30 amp service, but it doesn't address my question.

#8 wire is good for 50 amps. If the wiring has been installed in a metal conduit or metal jacketed flex that is the ground as long as the conduit (or flex) goes all the way back to the main panal and the main panel has been grounded or sometimes called earthened. This is done by a (most often) #6 bare copper wire connected to 1) a copper ground rod, 2) connnected to the incoming water line (not done vary often anymore, or 3) connected to a Ufer ground (a 30 foot long bare copper wire embedded in the concrete foundation.

The black wire is phase A, red wire is phase B, and the white wire is the neutral or sometimes refered to as the common wire.

Hope this helps
pianotuna
Nomad III
Feb 16, 2014
Pull new #6 wire.
whiskyrunner
Explorer
Feb 16, 2014
Ask what is cheaper, your insurance deductable for the 5th wheel fire and electrical problems or the two hrs a electrician may charge you to do it right
24rules
Explorer
Feb 16, 2014
this is what I did I have worked as a electrician for 20 years.i would use the black and red as your 120 volt hots the white would be a neutral since some of higher tech high voltage appliances with all the integrated circuit panels need a neutral to work properly and then get a 8 ft. ground rod and drive it in the ground and the run a 10 bare or coated wire to the ground lug on your rv outlet or sub panel whichever you are using because in my area sub feed panels all need a isolated ground which you will create with the ground rod do this and you will be adequate for all the nec codes that I have dealt with
KATOOM
Explorer
Feb 16, 2014
VintageRacer wrote:
Get an electrician. I see problems with almost all of the advice given so far. A outlet must, in most states in the US, have a metallic ground connection back to the main panel, a separate non-locally-bonded white neutral cable, and a hot cable. You used to be able to re-mark cables with tape but that hasn't been allowed for a number of years, again in most states. Now you must use a indelible marker or paint. In some states, if a sub-panel is in a separate building with no metallic connection back to the building the main panel is in (like plumbing, telephone, cable TV or other electrical wiring) then a local bonded ground can be permissible. It is never permissible to either ignore local codes or to do wiring installations without a permit, regardless of if you own the building in question it's always illegal, as far as my experience goes. If you do it or not is up to you. If you can sort out the ground issue, you should be able to install a 50 amp style outlet but fused to suit the 8 gauge wiring, for 40 amps or 50 amps depending on the type of cable.

Brian

I agree.....especially if you're not knowledgeable about electricity. Dont want to harm you or your RV.

The only thing I dont think I saw anyone mention is, how far is this plug from the breaker box and how far is the RV from this source? 8/3 is a good size wire but is still only capable of delivering so many amps depending on how much distance it has to travel.
mikeh449
Explorer
Feb 16, 2014
white wire is always neutral you can tape color code any wire 40 years as a electrician power plant and navy Seabees go to lowes or home depot and get a ground rod and some green #10 wire and run separate ground
ohiopicker
Explorer
Feb 16, 2014
greende wrote:
The old 30 amp 220V dryer type outlets did not use a ground. They relied on the common (white) to provide the ground and common. This is no longer acceptable. While I do not know what your codes officer will say at anytime in the future, for now I would do as others have said and use the red wire and mark it with green tape.

I installed new Maytag electric dryers back in the 50's and 60's, and they always came with a length of 10ga. bare aluminum wire and a ground clamp for attaching to a cold water pipe. This was the ground wire. The white wire provided the neutal for the 120v. motor, timer motor, and inside lights used on the dryer. The heating element did not use the neutral, as it was 240v.
time2roll
Nomad
Feb 16, 2014
Pull a ground wire or even better, new 6/3 + ground.
Bird_chaser
Explorer
Feb 16, 2014
Where I live code for ground wire is unbroken/uninsulated. This way there is never any confusion. I suggested you hire a professional so there are no future issues.
greende
Explorer II
Feb 16, 2014
The old 30 amp 220V dryer type outlets did not use a ground. They relied on the common (white) to provide the ground and common. This is no longer acceptable. While I do not know what your codes officer will say at anytime in the future, for now I would do as others have said and use the red wire and mark it with green tape.

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30 AMP home wiring Question

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