Hoping the brain trust of the forum can help. On a new lease this year that we will need to set up plugs for the RV's. The owner is getting a meter dropped on a utility pole and I need to set up a RV 30 amp plug anywhere from 100-200 feet away. Will have a 30amp breaker in the box and I want to bury the cable so wondering what size wire to I need for this run? have a small knowledge of electrical work; put in a breaker, hook up a plug but do not know about wire size and voltage drop. Of course with the increased cost of materials I do want to be as economical as possible. Appreciate any help you can give.

a 10-2 will work it should be a 30 amp 110. i am a licensed electrician. hope this will help

This helps. Appreciate the info.

If you are in an area with gophers & moles, might want to think about putting the 10-2 in 1/2 inch PVC. They will eat thru the wire but for some reason will not bother the PVC.

I'm retired from the RV business/industry.

IF you are going to wire the receptacle yourself make SURE you get the right one and wire it correctly. I can't tell you number of 'fried' RV's we repaired over the years.

DON'T make this mistake:

https://www.myrv.us/Imgs/PDF/30-amp%20Service.pdf

Everything with a circuit board ruined.


And I strongly disagree with 10/2 wire for such a long run.

I went with 4ga wire in PVC for a 75ft run. Cant hurt to go a little bigger.

I’ll ask the I/E engineer at work on Monday for ya if I can remember.

For a 200ft run of 30a, 120v with 3% of source drop you need 4ga copper.

Appreciate all the input guys. This will not happen for a few weeks so I have time to continue to research. I see that there is a disparity in the advice on size. I have seen 8-2 and even 6-2 recommended.

Flintknapper - thanks for the link. I actually have the same one saved for reference!

For a 200ft run, 4 gauge is recommended.
You rather be safe than sorry.

If you are going to be connecting a travel trailer/RV to it and plan to run the A/C you are going to want at least 6-2 (if your run is over 100').

You might pull up to 15-17 amps at 'start up' on a 12K BTU A/C unit alone.... and if you've had a 30 amp trailer for long, then you know you don't need to be running much to max out 30 amps.

I don't know your set up or intended use, but it will be a bitter pill to swallow if you go too small on the wiring and have problems. Think of all the work and expense.

This is exactly correct for a 100% load at 30a.
But being that you shouldn't ever have a sustained load of more than 80% on a breaker I suspect the RV at full load with the AC running would not even get to that amount.

24 amp load figured at 3% drop is like this:

#10 cu is good to 60' (3- #10)
#8 cu is good to 95' (2- #8 & #10grd)
#6 cu is good to 150' (2- #6 & #10grd)
#4 cu is good to 240' (2- #4 & #10grd)

My suggestion if you are going between 150-200' is run aluminum in the ground in PVC and set a receptacle for the RV next to it.

#4 aluminum is good to about 145' at 3% allowed VD.
#2 aluminum would be good up to about 235'

Yes, up to 60' with an 80% load on it off the 30a breaker. Certainly not for 150-200' run like the OP is stating unless you want to smoke an AC compressor on low voltage.

There is a great app for sizing wire based on voltage, amperage, and distance: Voltage Drop by Southwire.

I'm no electrician, but I wouldn't run more than about 100 feet with 10 gauge, 125 feet on 8 gauge

edit: and those look a bit undersized by looking at the calculator values

I agree with a 120v 30a RV service PMK

Been doing electrical for 30+ years and I wouldn't run 10g cu more than 60' or so if using the AC in the RV.

But honestly it all comes down to the current draw that will be incurred.
If the OP can tell me what his trailer pulls on a full load I can size based on using 120v which really should be on the low side of the voltage just about anywhere now. Most places are closer to 125v then 120v.
The higher the voltage the less amperage issues you will incur.

The devil is in the details...I appreciate all the replies. Not sure exactly how much the a/c draws but I found on the rv forums that a 15,000 btu unit will draw from 13-16 amps on start up and then 12.5-13 amps to run. we have an rv fridge, coffe pot and microwave for the other big appliances but have found that we do not run the microwave and a/c at the same time or we will pop a breaker. Might need to rethink where my trailer sits and get it closer to the pole.

What we did for many customers with 30 amp trailers was to wire the A/C separately so they could run a line to an external source when camping where there were hook ups available. The draw back to 30 amp 110V trailers (vs. 50 amp) is that you MAX it out pretty quickly and end up having to learn what you can and can't run at the same time. Sounds like you've already figured that out. And Lord help you if the Wife/Girlfriend want to come along with their 2500 watt hair dryer, etc...

Most RV style Refrigerators run at a pretty low current draw. They start at about 500w and run at 150w-200w so they typically are not an issue with a 30a 120v service.

MIcrowave ovens and coffee pots are a different story. Most coffee pots will operate at about 1kw, or about 8.5 amps on 120v. So you can see with an AC running along with the coffee pot you are up to about 20amps or even a bit better. Turning on the microwave with both the others running will likely trip the breaker.

My suggestion is to assume the 80% allowable sustained load of a 30a breaker or about 24 amps and figure it off that and your idea of trying to locate a little closer to the power source is a good one unless you do not mind dropping a few coins to install the conduit/wire it will take to go the 150-200'. With copper prices today I'd seriously suggest going aluminum and just setting a small panel nearer your trailer and feeding from it.

And flintknapper is right about being a little bit hamstrung with the 120v 30a service instead of a 240v 50a but in most cases the 50a service is only used when an RV has 2 AC units or a washer and dryer.

X2.

I’m did 30amp on my 40’ container. That’s two AC units(8k and 5k), mini fridge, lights, microwave etc. Now my water heater is 1800watts so i only turn it on when we are going to use it, (it’s own it’s own circuit).

The only way I see a huge advantage to 50amps, multiple big AC’s and electric heaters. Multiple Electric heaters draw a lot

Now you are making sense.

Yep, just started looking at the price of wire and Oh MY?.....I might be sitting next to the pole!

It is insane

Here my hot sheet for this week on copper (per 1,000')
It's just crazy. #10 cu wire is sitting at over $.31/ft.
600mcm cu is at $17/ft. OMG




And aluminum

In your post you said RV's, but you are only talking about a single RV. Are there multiple RV's that need to be connected? If so, maybe you could put two RV's near each other and run a sub panel on a post in between them. Then instead of running a single 110 30A, run some 2-2-2-4 Aluminum between the two panels and size the main breaker to match the total of the two RV's. That will let you run the 110-30A for your trailer and give you the option of running a 240-50A breaker for the other trailer (if it's a 50A trailer). If you don't have two trailers now, the sub-panel will give you that option down the road if you need it(instead of having to run another 100' wire). In the grand scheme of things, the cost of a small sub panel and breakers is tiny and you can split it between the two of you. You also don't have to figure out how you are going to get a size 2 or 4 cable in one of those small RV outlet boxes. That's how we setup the two trailers at my current lease. I think we put an 90A breaker in the main panel and ran the 2-2-2-4 to a sub panel about 100 ft away. From the sub panel, we have on 240-50A trailer and one 110-30A trailer. Having the sub-panel also gave us the ability to run a dedicate circuit to the deck between the two trailers for some lights and a couple of power outlets.

For the cable, Amazon sells the 2-2-2-4. Just pick the length you need.
2-2-2-4 Aluminum cable

yes, planning on between 2 -5 trailers at this camp. Originally I was trying to avoid the cluster of trailers around the pole and was hoping to be able to space out a little. We have plenty of room with the only deciding factor after this thread being the cost to run the wire. After all the input and seeing the price's we might not be so far away from each other like I first wanted. Going out this weekend to scope out the camp area and see how far from the pole I can afford $$ to be.