Hi guys,I currently have an outlet installed on a pole by where I park the RV. The outlet is a 30a amp RV outlet and is 30a 120v (NOT 240v). It's fed directly from the panel with #10 wire connected at the main panel to a 30a single pole breaker.I would like to change out the outlet to a box that has the 30a outlet, along with a 20a GFI and two breakers, one 30a and one 20a, one for each outlet. This is an outdoor weatherproof box like you would see at a campground or RV park.Reasons for the change are:1) I like having a breaker so I can plug in the RV and then power it on. This eliminates wear and tear from arcing on the plug.2) It would be nice to have a convenience outlet there. I can't just add one without it being protected by a 20a breaker.Ideally I would like to feed this with the 30a 120v circuit that's already there. Most of the time the RV draws very little power, it's only trickle charging the batteries. It will draw power with the a/c on, so just won't be able to use the conveience outlet at those times. I'm not looking to increase power capacity at the outlet, and I have no need for 240v there, it would be nice to plug in an extension cord without having to unplug the RV.Can I feed this new outlet with the existing circuit, or is this considered a subpanel because it has breakers? Do I need to feed it with a 30a double pole breaker like it was a sub panel?I know I "can" wire it from the existing circuit with no issues but am wondering if anybody knows what the NEC rule is on this.

Whenever a circuit is added it must comply with "worst case" scenarios as far as connections and wire size are concerned. Which includes load device NEMA ratings. Because of liability considerations you really should check your local building code specification at your local regulatory agency (where you get your building permits)

All I can tell you that new installs require a means of disconnecting the power at the box if it is more than a certain distance from the meter. I Believe 50 feet but my memory is not as good as it used to be.

Mex, I understand that. The 30a breaker in the main panel protects the #10 wire going to the outlet and the 20a breaker at the new outlet protects the GFI. I have no doubt it will be safe, the question is what the code says about it.

Need to pull new wire. Codes requires 2 hots, a neutral, and a ground from the main panel. You can use 10ga for ground, but will need 6ga minimum for the hots and neutral and a 60A breaker. The reason being, if you kept the 10ga wire, there is a possibility for an overload if using more than one of the receptacles. Not to mention that those boxes are wired for 2 buses with 2 120 lines.I did this same upgrade a couple years ago and have not regretted it. Having a port available for my welder has been nice too.If you don't want to do all this, can you use an exterior receptacle on your RV as your "convenience" receptacle?

darsben1 wrote:All I can tell you that new installs require a means of disconnecting the power at the box if it is more than a certain distance from the meter. I Believe 50 feet but my memory is not as good as it used to be.True to an extent. There is a "6 disconnect" rule that states that if there are 6 or fewer breakers, a main disconnect is not required.

RV Outlet NEC Code Question | Good Sam Community

MEXICOWANDERER
Explorer
Aug 22, 2017

Quick! Unplug It!
BurbMan
Explorer II
Aug 22, 2017
OP here, and sorry to stir up so much dust on this one, I guess the NEC isn't as clear cut as I thought...

Once again, it's a question of convenience, not capacity. The TT stays plugged in while at home to power the converter to keep the batteries charged, so drawing almost no power. I like having 30a service there for the 1 or 2 times per year I will use the a/c in the trailer.

I like the idea of a 20a outlet on the power pole in case I want to plug in a hedge trimmer or similar. The TT does have an outdoor convenience outlet on it, but it's on the side that faces the fence. Having an outlet in the pole saves me about 25' of extension cord.

So if the TT is running the a/c, that means folks are staying in it, and obviously I am not running a hedge clipper.

Just to be clear, I am planning to install the new box with breakers, and I'm not planning on having it inspected. Although I am a DIYer I am quite knowledgeable about electrical wiring and code requirements. This post was mostly a point of curiosity about whether this installation would meet code or not, it;s not a safety issue since the 10 gauge wires are protected by the 30 breaker in the main panel.
rjniles
Explorer
Aug 22, 2017
I guess we have to agree to disagree. If the poster is having the install inspected he should ask the local inspector for his interpretation. If no inspection then he can do as he sees fit. Neither install is dangerous.
soren
Explorer
Aug 21, 2017
rjniles wrote:
Article 551 has been discussed in a few of theses posts.

A minimum of two RV spaces are required to use Article 551 for site wiring.

The feeder to the RV panel is required to be sized for the expected loads. That doesn't necessarily mean a full 50 amps, but it doesn't necessarily mean 30 amps is sufficient either. What is the actual load of the RV and what is the actual load of the equipment you wish to connect to the 20 amp receptacle?

By installing the new RV panel you are changing this circuit from a branch circuit to a feeder. That means you will need to install two ground rods at the new panel. That's the impact not using Article 551 has on you. 551 does not require ground rods, but not using 551 requires them to be added.

Sorry, but the fact that 551 defines an RV park as having two or more sites for the temporary use of RVs does not mean that an inspector has to ignore the means, methods, and materials used to distribute power to an RV distribution box, or the code requirements of doing so. Nor would he, or she, necessarily default to the installation being a residential sub-panel. That is WAY too much supposition on your part. Second, asking what the load is on the OP's particular RV makes it clear that you are reading a section with little understanding of what you are looking at. The minimum branch circuit for a combined 30/20 120V pedestal is 3600VA, or a thirty amp breaker, the demand factor is 100%. Demand calculations are not required as it is spelled out clearly in the section. It's obviously a decision to be made by the individual AHJ, but I serious doubt that you would ever hear, "this jurisdiction is deciding to ignore the code section that clearly delineates how to wire an RV supply pedestal, since technically you aren't installing two of them" Do you even know if a typical pedestal is listed and labeled as a sub-panel?
MERVer
Explorer
Aug 20, 2017
Why not plug into an exterior outlet that's on the RV instead... I'm assuming that you already have one.
Ralph_Cramden
Explorer II
Aug 20, 2017
This thread is like the
rjniles
Explorer
Aug 20, 2017
Article 551 has been discussed in a few of theses posts.

A minimum of two RV spaces are required to use Article 551 for site wiring.

The feeder to the RV panel is required to be sized for the expected loads. That doesn't necessarily mean a full 50 amps, but it doesn't necessarily mean 30 amps is sufficient either. What is the actual load of the RV and what is the actual load of the equipment you wish to connect to the 20 amp receptacle?

By installing the new RV panel you are changing this circuit from a branch circuit to a feeder. That means you will need to install two ground rods at the new panel. That's the impact not using Article 551 has on you. 551 does not require ground rods, but not using 551 requires them to be added.
enblethen
Nomad
Aug 20, 2017
Soren; You are correct in some ways. many times when attending and giving code classes, I have seen numerous 'electricians walking out after the basic portions of the NEC has been covered.
soren
Explorer
Aug 20, 2017
enblethen wrote:
If you look at 551, you will find that you must also follow parts I, II, III, IV and V of the code.

Unfortunately, it's a little more complex that that, as some sections supercede others, particularly when it comes to feeder conductor calculations, and things like installations AMI and the opinion of the AHJ will directly impact individual installations. The larger issue is that RV supply work is much different that residential work, which is the source of a lot of the uniformed "advice" provided here. Take the multiple "experts" that claim that you need a ground rod(S) and that it needs to be treated as a sub-panel. Neither are correct, and in fact, a code committee revisited the grounding issue during this most recent cycle and specifically determined that a rod at each "Stand" was not desirable, or required.
Chum_lee
Explorer
Aug 19, 2017
Am I missing something here? To the OP. Doesn't your RV already have an exterior weather proof 120 volt duplex convenience outlet wired to the load center inside the RV? (mine does) One could easily add one if it doesn't. Why not use that or the exterior plug for the refrigerator? If your RV is absent and you need a 120 volt 20 amp plug at the pedestal just buy a simple 30 amp to 20 amp 120 volt adapter and your done. Or . . . . is this 120 volt 20 amp plug for something permanent?

Chum lee

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