Hey folks....
I may do a job for a fellow who wants to rent
out parking spaces for RVs. Some will be inside a building
and some outside. Of course money is an issue. Instead
of buying those small RV loadcenters, the ones with the 50
amp and 30 amp receptacles built in...150 bucks each....
well...I'm looking for ideas how I could install these same
outlets in the spaces outside ? Do they make "in use" covers
for these outlets? This is just a storage facility and only
minimal amperage will be required for time time to crank up
the AC for air circulation. I'll probably put two spaces on the same circuit.
Any ideas appreciated....

Talk with your AHJ for what they may consider acceptable since this would not be an RV park in my opinion. Some things would not likely change such as the need for disconnecting means which is why I like the prebuilt units. That said, they do offer, or at least in the past, weatherproof covers for this size of receptacle. The weatherproof cover I have on my trailers connection at my house is a Taymac.

Loading is the big area to discuss with the AHJ. Likely you will need to tap off a feeder which requires overcurrent protection for the receptacles, another reason for the prebuilt units. Otherwise if the loading and if manually controlled cylcing of AC's (which I doubt will happen)could mean that a 30 amp feeder may provide power for all 30 amp receptacles, and a 50 amp feeder for the 50 amp receptacles. I would not approve this myself because rather than manually cycle the AC, the AC will be left on (likely a high setting) as soon as I leave and over load a shared small feeder.

Lastly depending on the code cycle and code interpretation, be prepared to install grounding electrode (ground rod) at each disconnect due to the 2008 NEC 250.32 and the diffinition of a structure in 2008 NEC 100 "That which is built or constructed."

Though this does not pertain to you, I am inclduing this for information for others. As this is storage it is not a good idea to plug in and leave a trailer connected up full time for extended periods as batteries will overcharge and be ruined. Yet to leave a trailer disconnected from any power source will discharge the batteries and leave you in the same bad spot (it is amazing how fast just a propane detector can drain batteries). I recommend removing the batteries during storage and an occasional trickle charge. A battery disconnect installed on trailers with gel (starved) cell batteries which can be switched on for 1 day a month would also work, but is not a good idea for wet cell batteries.

I agree you need to see what your AHJ has to say about this but I would think that the rules are somewhat relaxed since these are not really living space while they are in storage.
If you wanted to go high tech I would consider a system that cycled the power around the various outlets with X10 technology so in a group of, say 10, only one was on at a time. If you can get everyone to agree this is an "installations under single management, where documented safe switching procedures are established" you can probably use the line cord as the disconnect in addition to a central disconnect.
At that point you could probably get away with a receptacle in a big Bell box enclosed in a little "bird house" type structure to keep the rain water off it but you might still be getting close to the price of the RV load center by the time you are done. I bet if you bought the RV box in bulk you can beat your local price.

Thanks...you guys bring up some very good points.

The owner wants to have both the 50 and 30 amp outlets
available at each space to accommodate any size RV that may
come in. I did think of building something for the outlets
to shield from the weather. I intend on sharing one 50 amp
outlet with the space next to it...and the same with the 30
amp. In the buildings its not an issue, plenty of places
to mount 4 and 11/16" junction boxes with raised covers.
Its only in the outside spaces thats a problem. The RV
loadcenters would really almost be a waste because there
would never be a demand for that much power. The owner is
going to install 6x6" posts at the rear of each space.
All power will be in PVC....I just need to come up with
something other than the RV boxes. I will mount either
a 200 or a 125 amp loadcenter near the center of the spaces.
This is a 5 acre storage facility and will have maybe 2 places where 8 RVs will be side by side.
I will talk to the local State inspector and get his input..

Site351:

While I can appreciate your concern for saving money, I'd still seriously consider the factory RV units. These would result in a significant labor savings which is something that is of value to someone. I am pretty sure that there are units made that just house the two receptacles with no breakers or pedestal. Those might be worth exploring since I seriously doubt that they cost as much as you were saying.

You have to admit that these will provide you with a much more professional installation as well.

It's like when people say "if you buy $10,000.00 worth of replacement windows, they will pay for themselves within two years". My answer is, OK, how about I pay for them over two years with that savings? If I had a spare $10K, I probably wouldn't be too worried about a few extra bucks a month on my electric bill.

Thanks Ed....

could someone pull up a link to the RV loadcenters you
are suggesting ?

I saw one at a wholesale house and it had the breakers,
outlets and a built-in GFI.
I have to agree about the professional look....
everyone wants to save money, but they want it to look nice too. Cadilac job for the Chevy price...lol