Installing an RV Subpanel 50/30/20 amp

[MtCamper]

Johnny Law, I'm assuming your main is surface mounted. You state you plan to install the sub no more that 6' away. How many spaces are available in your main? If you have at least 4, I'd return the sub panel and purchase 3 separate exterior boxes. One larger for the 240v 50amp, and two smaller ones for the 120v outlets. I'd use a very short piece of electric conduit between each box and the main and rely on the breaker in the main panel for power. I'd use 4 strand 6 gauge copper for the 50 amp, 3 strand 10 gauge for the 30 amp and 12 gauge for the 20 amp. your 20 amp outlet will need a GFI. If you want the sub regardless, I'd use #4 copper for that short run off a 100 amp breaker in the main. Again, 4 strand in conduit for a surface mount. For any longer runs to a sub, I'd go with 2-2-2-4 aluminum due to cost.

All the advise you get here is free. May or may not be worth the cost.

[rarebear.nm]

The OP also wants a 20amp outlet. IMO his plan is a solid and safe solution. When I plug-in a RV I turn off the breaker. That would be pia if the breaker was inside. At home we have two RVs parked and each has a dedicated box with breaker.

[Persistent]

Originally Posted by Johnny Law

Good day all,
I searched the forums and couldn't find information for installing a RV sub panel on the outside of my garage. I purchased an RV sub panel that has 50/30/20 amp service. Each has their own breaker in the box, directly above each plug.

I am installing it on the same wall as my house main breaker panel and no farther than 6' from the main breaker pane. What size breaker and wire do I use in my main panel to feed the sub panel? I am planning on using the 50 amp and 30 amp at the same time when I have friends/guests at my house when my 30 amp trailer is plugged in. I will also be using the 20 amp for my tractors and lawn mowers battery tenders. So the panel will be getting used, a lot

I think I know the answer but I would like to reassure my guess before I purchase the breaker and wire. I will spend the money and use copper wire.

Thank you all ahead of time.

Similar to this one (suppose to show an image):

https://www.homedepot.com/p/GE-RV-Pa...32SS/203393689

It is a 100 amp load center. I assume it needs to be connected to a 100 amp 240 volt breaker in the main service panel. Look up wire size for 100 amps in code ampacity table. Can your main service panel actually accept a 100 amp 240 volt breaker?

The 50 amp 240 volt breaker connects to L1, L2, Neutral and Ground from the 100 amp feed.

The 30 amp probably connects to one leg and the 20 amp probably connects to the other leg of the 240 volt 100 amp feed. Check to see if this is true.

The alternative is both 30 and 20 amp are connected to same leg of 240 volt feed. This is possible, but not likely.

Any way you slice it, you can use all outlets simultaneously with a 100 amp feed. If 30 amp and 20 amp are on different legs, you could get by with an 80 amp feed and still use all outlets simultaneously. So, an 80 amp 240 volt circuit breaker in the main panel. Do breaker companies make such a thing?

You could use a 50 amp feed. You could use all outlets. However, the main 50 amp breaker in the service entrance may trip if all outlets use the maximum output.

How likely are all outlets to draw maximum current at the same time? Your main service entrance panel probably has more branch breaker capacity the the main breaker. You do not use maximum on all branches at the same time.

[bigb56]

It would be impossible for the two single pole breakers to be on the same leg on that panel or any other modern panel unless someone removed a full size breaker and installed a twin. BUS=A-B-A-B

[Johnny Law]

Thank you all for the feed back. There is a lot of knowledge and experience here. I truly appreciate help.
I did check my sub panel and it is rated for 125 Amps.
I bought it from Jamestown Advanced Products. It wasn’t cheap but it is what I was looking for. From your feedback, I get a sense of relief that they made a great product.

I am going to go with a 100 amp feeding the sub panel from the main breaker so I don’t have to worry about being under rated in the event my fiends 5th Wheel pulls 50 amps at the same time my Airstream pulls 30 amps. Yes, I am aware it is probably over kill but if I have plugs available, I will use them. Maybe the 50amp for my welder too ��

I truly appreciate everyone’s help. Thank you so much.

PS: I am taking a two year Marine Maintenance Technology course at my local community college and next quarter will be Electrical II where it’s all about AC, solar, generators, etc. all transferable to my Airstream. Gonna upgrade my 650 watt solar system to a 3KW.

I took advantage of a Black Friday sale and purchased a soft start for my Airstream’s heat pump. Too. Gonna install over Christmas break.

[KJLarson]

Unless you are an electrician this should be left to a professional. DIY is fine when you have the in-depth knowledge needed to safely do something. I have decades of experience with electrical systems and am concerned with some of the answers posted here. Wattage, amperage and wire size are all critical to a safe installation; the National Electrical Code is one place you can look for the minimum requirements for your installation.

A couple of things to consider: One, should you install the system yourself and it does not meet code and you have a fire as a result of improper installation your insurance company may decline the claim leaving you responsible for repairs. Secondly, when you sell your home an inspection will find the improper installation which can imperil the sale or you could be required to have it removed or corrected to complete the sale.

If you insist on doing this yourself please research what is needed from reliable sources; asking questions on blogs is OK but I prefer going to a professional. Talk to an electrician for advice; most will provide it as a courtesy especially if you buy the parts from them. When we were having our home solar system installed several years ago I asked the electrician doing that install about installed a 30 amp circuit for our TT; he provided me with the correct wire, circuit breaker and told me how to do it at no cost.