Hardwiring For Direct Power, House To RV

[vicki2700]

I'm fixing to add a new breaker to the house box and run a line outside to a weatherproof receptacle for an RV hookup.

Does anyone with personal experience doing this have any tips/suggestions? I hope to do it asap.

Thanks!

[wolfe10]

Vicki,

Welcome to the FMCA Forum.

If 30 amp, you will need one hot, one neutral and one ground.

If 50 amp, you will need two hots (out of phase), one neutral and ground.

Wire gauge depends on which amperage and length of run.

Obviously, it must be wired correctly!

[elkhartjim]

Simple suggestion, if you don't understand exactly what Brett just stated, hire a licensed electrician. If the wiring is not done correctly you can do severe damage to your motorhome or worse, yourself.

[vicki2700]

Thanks - I was actually wondering about a 50amp breaker even though my RV is only a 30amp. I am a full-timer and I need to run a 1500 Watt electric heater in these Midwest winters. My hope was with a 50amp I wouldn't have to turn off the heater to run the microwave - or the a/c in summer?

I'm going to guesstimate about 100' of wire will be required. I will fish it thru some insulated conduit of some sort.

If I recall correctly, there are surge protectors that install at the shore power, also - it would be nice to put it all in one weatherproof box!

Thanks again! I'd better get to doing some shopping!

[vicki2700]

Simple suggestion, if you don't understand exactly what Brett just stated, hire a licensed electrician. If the wiring is not done correctly you can do severe damage to your motorhome or worse,

yourself.

Not to worry! But thanks!

I have a construction background and a fair amount of experience with residential electric.

[tbutler]

If your coach is 30A there will be no advantage to installing a 50A box unless you think you might upgrade to a 50A coach in the future. No matter what you plug into, your coach will only have 30A. Your 30A coach should handle a 1500 W heater without a problem. Having 50A at the outlet, you will still have the same problems running the heater and the microwave that you would with a 30A outlet.

Using 100' of wire is a concern. The longer the wire, the heavier it must be to deliver the full current at the other end. A wire capable of handling 30A may deliver only 110V instead of 120V at the outlet after 100' of wire. This web site has all the information you need for planning your external power outlet. Be sure to look at the information about wire length and recommended gauges. A #10 wire will support 30A with a 25' wire, it takes a #8 wire for a 50' wire and #6 for 100' wire length according to the table on the web site.

Every job is different. I have installed underground line to a remote pad at my daughter's home and an installation on the side of the garage at my mother's home.

Surge protectors are made to be weatherproof if they plug into the outlet at the post in a campground. If you want the surge protector inside, you'll have to build a shelter to accommodate that. Get dimensions for the model you want to install before building anything.

[vicki2700]

Oh, OK - thanks for the info on the amperage! I grew up in racing, I was thinking it might be like adding nitro to have the extra power on reserve?

Thanks for the website, too. Yes, years ago we ran full hot lines from a house power source to a remote for my 40' 5th wheel with full overhead cable. That we used an electrician for!

[kaypsmith]

Not a bad idea to run 50 amp as the wire will the most added expense. You can purchase 3 outlet box like found in most campgrounds today. Your 30 amp can be plugged into the 30 amp outlet

without an adapter, and you can run a heavy duty extension cord into the rv on the 20 amp outlet to use the 1500 watt heater that you mentioned plugged into that, be sure the extension cord is a 12 gauge. When you upgrade to a 50 amp rv in the future, the wireing is already done.

[billbaldwin]

Run as much service as you can afford

I started with a 30amp 5th wheel and ended up with a 50amp MH

Now I need to plug in both

I was lucky I set a CG box

50amp

30amp

20amp

Ran a dedicated 100amp service to the box

[wildebill308]

That is a good suggestion to run a heavy duty extension cord for your heater. I have done this in the past on a 30 amp rig.

I bought a 10 gage extension cord from Home Depot. I could run two heaters one on the extension cord and one on the 30 amp cord and stay nice and warm.

Bill

[skipsaunders]

if you are running the line outside, be sure that you bury the line according to code.... minimum depth is commonly 18" but it might be deeper where you are.

[hermanmullins]

Tom,

I will disagree with you about pluging a 30 amp cord, with adapter, into a 50 outlet. The one leg of the 30 amp cable will be on a 50 amp circuit breaker.

Herman

[wolfe10]

Let me clarify Herman's comment.

What is at risk (admittedly very small risk) is your shore power cord, ATS (Automatic Transfer Switch) and wiring to your coach main breaker box.

From the main breaker box onward, the breaker box main 30 amp breaker and individual breakers protect you. But, if anything drew over 30 amps "before" the main breaker box (a partial short for example) the wires are undersized for more than 30 amp load. But, a partial short is very rare. And a regular/dead short will trip either a 30 or 50 amp breaker.

So, yes, there is a small risk. One most of us acknowledge and accept. Checking wire connections as part of an annual inspection gives even a larger degree of confidence. I am talking about checking for cleanliness and tightness the connections at coach shore power inlet, ATS and breaker box. Also that the shore power cord ends are not burned or showing signs of overheating. Just basic maintenance practices.

[vicki2700]

I love all this interaction, thanks so much!

With my history in construction & building I'm perfectly comfortable with the 'shore' wiring aspect of this project - what I'm unclear on is the actual motorhome wiring itself - for instance: if you plug the power cord into the junction box inside the cabinet when the source is the generator, shouldn't you be able to plug the dedicated line from the house into the same receptacle to power the motorhome?

Plug the house into the RV instead of plugging the RV into the house?! haha!

I have a small 2008 C class and a couple years ago I had to replace the whole power converter. I'm fairly certain something behind it is wired wrong, as there are no regulations or quality controls in place in this industry...
But that is a project for another day!

[wolfe10]

Not sure I understand how your coach is set up.

Do you have an ATS (Automatic Transfer Switch) or do you have to manually plug generator or shore power to get 120 VAC to the coach?

And, if you are talking about powering the house from the RV generator, that is a HUGE no-no unless done properly. Generally this is done to power the house in the event of a power outage. You will need an electrician to install basically a "transfer switch" on the house side breaker box. Were you just to plug in, you would be powering the power company grid and could electrocute someone working one the line. You only want ONE source of 120 VAC. So, either generator or shore power in your RV. Same for your house-- either grid power of (grid power disconnected) your RV generator.

[Sundancer268]

Make sure you have a breaker at the receptacle so you can plug in and disconnect with out a load on the circuit. This will prevent the plug and receptacle from being damaged from the arc caused by a load when connecting and disconnecting.

Almost every camp ground I go to the circuit breakers are on and I have to turn them off prior to connecting and this tells me that the previous occupants are not knowledgeable about the electrical system and its potential for future problems for their unit and other people who follow after them.

I did install a camp ground box on the side on my garage with all three receptacles for my coach and family members who stop by and am very happy with it. It sure beats the extension cord under the garage door any day.

[vicki2700]

Thank you Sundancer, good point!

Wolfie - good heavens, no!

I hope I was only confusing due to working till 4am!

In fact I believe I shall nap again before work this afternoon - thank you all again! I hope to have this done immediately.

[w8aef@q.com]

Please remember that buried cable must be derated as compared to wire not in conduit.

You are looking at large (expensive) conductors for a 100' buried run.

[ClayL]

I rented a trencher and I friend and I dug the 18" deep 100 foot long trench.

I hired a licensed electrician to do the wiring but had to download the proper wiring and receptacle for him. He thought it would be a 220 connection.

I also calculated the wire size for the 100 foot distance. He apparently thought if the wire ampacity was okay then length didn't matter. I allowed for about a 3 1/2 percent drop (from 120 down to 115 volts) at the 30 amp draw and had him use 8 gauge wire instead of the 10 gauge he wanted to use.

I have a 30 amp motor home and considered installing 50 amp service but the cost was higher than I wanted to pay. I put in two boxes so had more wires to run. My friends that come visit can use a 50 amp to 30 amp adapter if necessary.

I used an 8 foot pressure treated 4X4 and set about 3 feet in the ground for the boxes at the RV sites.

I also trenched about 150 feet to the sewer clean out in the back yard and buried a 1 inch PVC pipe from the RV sites close to it. At each end there is an in ground valve box with a female hose fitting. I run a short 3/4 inch diameter hose to the clean out from one and a longer one from the RV to the other one at the RV site. That way I can dump the tanks using a macerator.

[wayne77590]

Some useful information.

RV Electric