RV Outlet NEC Code Question

[BurbMan]

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.

[MEXICOWANDERER]

Quick! Unplug It!

[BurbMan]

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]

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]

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]

Why not plug into an exterior outlet that's on the RV instead... I'm assuming that you already have one.

[Ralph_Cramden]

This thread is like the

[rjniles]

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]

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]

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]

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

[MEXICOWANDERER]

What am I learning here?
I know I know!

I wandered into a minefield...

Carefully back out. Each foot put atop a foot print made when entering...

"Whew..."

[enblethen]

If you look at 551, you will find that you must also follow parts I, II, III, IV and V of the code.

[soren]

enblethen wrote:
Soren:
You may want to look at Art 225 II 225.30

Because? It has what exactly to do with Art 551, that actually covers the installation of RV electrical supply equipment?

[soren]

myredracer wrote:

soren wrote:
Electrical questions are always pretty entertaining on the forum, usually because there are plenty of wrong answers, but this one is in a league of it's own.

I will tell you one thing for certain, I would never ridicule anyone on a forum simply because I did not agree with their opinion, esp. if I thought my opinion is superior because I happened to think I have more training, education, experience or qualifications. And I would never post any comments along with a note that I am a PE (ever...).

You want to guess how many times members here have, in the past, recommended doing things like hooking up a 30 Amp. trailer receptacle to a 240V feed? I'll give you a clue, it's far from unusual. I would have no issue with calling out a member who recommended a pressurized water line repair with duct tape, if I was a plumber, or a recommendation to put bacon grease on a second degree burn, if I was a nurse. Because you have access to a keyboard, and an opinion, it doesn't mean your opinion is safe, correct, or remotely in keeping with standard, let alone best practice. As for your claim of never mentioning your qualifications and experience, do I need to paste the fact that you did just that, a few posts ago?

soren wrote:
How many of you would expect to find pairs of massive feeder conductors, as in 3/4" diameter wires, bolted inside of a 50 Amp pedestal, with no breaker that size anywhere. How many understand a ten foot tap rule? RV park wiring has lots of things a typical residential electrician might find odd, or even wrong.

As I noted earlier, ALL of this depends on the local inspector, and they may be extremely competent, or clueless.

The OP's initial query is of a pretty basic & simple code nature. How are comments like the above and others you've made helpful in clarifying the OP's situation. I even commented that the OP could go to the Mike Holt electrical forum (where there are electricians, engineers, inspectors and other electrical experts) if he still had any doubts. How many homeowners even take out a permit to install an RV recept./pedestal? Not interested in debating the different methods for wire pulling and when to.

eom...

I doubt most homeowners take the time to permit a pedestal installation, and rightly so. That said, it has nothing to with sub-panels, ground rods, or a lot of "advice" offered here. Most DIY work has a whole lot of room for error, sadly, electrical work doesn't. There have been countless reports here, over the years, of extensive damage to RVs, caused by clueless DIYers, and incompetent residential electricians. There have also been reports of DIYers doing incredibly stupid and dangerous things, then offering advice. Things like illegal home generator backfeeds. You might be OK with never calling out anything, or hurting any feelings, but I'm not.