RV (Rec Veh) wiring question

[FastEddieB]

Quick background:

We finally got power in the form of a transformer and temp pole at our Lenoir City airstrip property:

It has two breakers and two 20A GFCI outlets. The meter has since been installed and powered up.

We're trying to get temporary power to our RV parking area about 100' away, and are running conduit underground to do so.

Problem is, we'd like to get 30A service there to run our air conditioner and microwave, which can tax 20A service at a distance from the power source. The contractor said the utility company said no modifications can be made to the temp pole once inspected.

I had a thought that I suspect might have something wrong with it...

Could I just make up a "Y" connector joining the two 20A outlets into a single 30A RV receptacle. Pardon my kindergarten art, but:

Seems like 20A parallel with 20A should be plenty to provide 30A (40, actually).

Where am I going wrong, or is this doable - if unconventional.

This will only have to serve us for the next year or so until our hangar is built - then we can do proper wiring into the panel at the hangar while still utilizing the wiring already in the ground. We'll unplug whenever not at the property.

 

[Skip Miller]

You need to find out if your two 120 volt outlets are on the same phase or are different. Test this with any sort of voltmeter that can handle up to 250 volts. Measure between the hot sides of each outlet. The answer will either be 240 volts or zero volts. If you measure 240 volts, NO! STOP! DO NOT PASS GO! Using the rig you have diagrammed above, you will create a direct short circuit across the 240 volts and ... well, it could indeed be exciting. The best that can happen is you will blow some breaker upstream of your receptacle box, and the worst that can happen involves a 911 call and some red trucks with lots of flashing lights.

 

[Shawn]

Yeah...don't dot that. You can blow chit up.

You are running conduit...meaning you are gonna hard wire into the box anyway right?

Just slap a 30A breaker in place of the 20A and don't broadcast it...or add a 30A in the panel...looks like there is space.

Do it right and ask for forgiveness later...or is your contractor a too by the book kinda guy?

 

[SoonerAviator]

Yeah, I'd just swap the breaker and go on with it. I'd claim ignorance if they noticed it (unlikely) and tell them I have no idea what they are talking about.


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[FastEddieB]

Thanks.

In reconsidering mode, which is why I asked.

Had not considered them being of different phase.

We cannot hard wire into the box per the utility company. So whatever we do has to utilize the existing 20A receptacles and breakers. Any modification could put the contractor - not an alectrician - on the utility company's poop list, and we don't want to do that.

All of this goes away once we have the hangar built - ultimately the main panel will be there and power will run to the RV parking from there with no restrictions.

 

[Shawn]

If you are looking at a year long use...it may be well worth it to have a 30A plug installed properly then. Sounds like a serious oversight on someones part of what that panel was needed for.

That should not be more than an hour of time for an electrician, permit, and possibly an inspection fee to do it right.

Another option may be run two 20A services to your RV with 10AWG cable at and split off your air on one circuit and microwave and shore power on the other...all depends on how hard wired your RV is.

Also, if you are just running extension cords to those plugs...be sure you are using a true 20A connector. Those typically have one blade at 90 degrees to the other...almost all traditional U Ground Edison on household extension cord type connectors are only actually rated at 15A. Try and run your 30A load through a 15A connector in a 20A service from one of those outlets and you are asking for meltdown before breaker trip. Looks like the panel receptacles are 20A.

 

[FastEddieB]

My guy was in direct contact with the head guy at the utility company. He basically was told two 20a circuits was all a temp pole could be fitted with.

Yes, it would be straightforward to modify the box for a 30A RV outlet. But not anywhere in the utility company's playbook, apparently. We're the first to get power and water in the development, so are kinda serving as guinea pigs as to what is and isn't kosher.

 

[Shawn]

My guy was in direct contact with the head guy at the utility company. He basically was told two 20a circuits was all a temp pole could be fitted with.

Yes, it would be straightforward to modify the box for a 30A RV outlet. But not anywhere in the utility company's playbook, apparently. We're the first to get power and water in the development, so are kinda serving as guinea pigs as to what is and isn't kosher.

Which is odd...since almost every temp power service I have ever dealt with especially for a new construction site typically involves a 50A Temp Power twistlock pigtail and 50A breaker so the contractor can drop a 6/4 cable and jobsite temp power box to run their heavier tools off of where they need them. Two 20A plugs in a fixed location seems woefully inaequate for most job sites.

 

[FastEddieB]

I'm clearly getting the info second hand.

I will probe farther when I can about other options, if available.

 

[SCCutler]

Which is odd...since almost every temp power service I have ever dealt with especially for a new construction site typically involves a 50A Temp Power twistlock pigtail and 50A breaker so the contractor can drop a 6/4 cable and jobsite temp power box to run their heavier tools off of where they need them. Two 20A plugs in a fixed location seems woefully inaequate for most job sites.

It does seem very odd that you'd have only 2x 20A circuits allowed.

 

[TheGolfPilot]

I saw the picture and my stomached dropped. The mere thought of having to charge my car there makes me uncomfortable (would take FOR EVER)

Anyway, electric car forums go into a lot of conversation about this. If the two plugs are on separate circuits you can do it.... do I need to put a disclaimer in here?

 

[deonb]

Contact Quick220.com

Their primary product is one where you plug into 2x110V outlets to get 220V. And to do this in a way thats at least semi-safe. (If you just hotwire these you'll have a male plug with live poles - not good).

Anyway, I know quick220 have other products that let you draw more amps from 2x110V instead of more volts - just send them an email.

 

[FastEddieB]

I am not in any way defending my harebrained scheme, which has been abandoned, but...

...perusing the internet to confine wiring for a 30A RV receptacle I stumbled upon this:

So I'm not completely alone in my imaginings. And I note the same warnings that Skip Miller started out with.

Image from here:

http://www.dmbruss.com/zFullTimeLifeStyle/FTLS_ElectricalAdapters.htm

As an aside, if we do use true 20A plugs and large enough wire, we might be fine running the air or the microwave as long as we don't do both at the same time. The problem with voltage drop I had before was a result of over 100' of standard extension cord.

 

[jsstevens]

I am not in any way defending my harebrained scheme, which has been abandoned, but...

...perusing the internet to confine wiring for a 30A RV receptacle I stumbled upon this:

So I'm not completely alone in my imaginings. And I note the same warnings that Skip Miller started out with.

Image from here:

http://www.dmbruss.com/zFullTimeLifeStyle/FTLS_ElectricalAdapters.htm

As an aside, if we do use true 20A plugs and large enough wire, we might be fine running the air or the microwave as long as we don't do both at the same time. The problem with voltage drop I had before was a result of over 100' of standard extension cord.

You can run big wire to solve the voltage drop regardless of the breaker size. And you should! Voltage drop will kill AC motors. Run #8 if you can. Even if you have to trim a few strands off to get it into a 20A plug terminals. Then you can be judicious with the microwave, toaster etc. You could even run a separate set of wires and thread an extension cord into the RV for plug in loads.

John

 

[PaulS]

Might be easier to break out the microwave and AC and make sure they run on separate circuits, sounds like 20 amps would run each one fine. Maybe plug the microwave directly into the cord. Better yet, since you are running conduit, run wire that can handle 20 amps up to the RV then cords from there.

 

[deonb]

Might be easier to break out the microwave and AC and make sure they run on separate circuits, sounds like 20 amps would run each one fine.

The AC on most RV's (mine included) won't start on 20 amps. It will use less than 20 amps when running, but it will trip a 20 amp breaker (or generator) when it starts.

 

[Shawn]

So I'm not completely alone in my imaginings.

FYI, that adapter takes two 30A 110v outlets and allows you to use a 50A 220v plug on a three pole four wire connector (two hot, neutral, ground). That does not combine the two 110v legs like you were thinkin...you still need 110v on a single hot, not 220v.

 

[FastEddieB]

Yep. My "Y-connector" idea is pretty much out the window. Blowing chit up is fun, but maybe not in this context!

As an update, have the conduit and wire run, along with the water to the camping area and gravel.

Stub at temp pole:

Water and stub at RV parking:

And the fresh gravel:

Things are gradually coming together, slow but steady.

Next trip up wiring the 20A circuit to the camping area is on my agenda.

 

[SoonerAviator]

Seriously, just have them add the breaker/outlet you want in the panel and re-inspect if necessary. It beats having to get adapters and jury-rig things just to get the a/c or microwave going. Unless the cost outweighs the price of a generator, I'd do it just for convenience.


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[flyingron]

You can't just up the breaker without installing wiring that is of sufficient ampacity. The breaker is sized to the wire. The wire is what determines the ampacity.

 

[FastEddieB]

I spoke with my contractor yesterday. I had forwarded this thread to him and he had read it.

He said he tried any way he could to have them approve a higher amperage outlet for the temp pole. He said there had been so much abuse, largely by boat owners, of high amperage temp poles getting made permanent that they had to buckle down. Hence the strictness on the 20A circuits.

I may have an electrician come by to get a second opinion - my contractor said he'd be fine with that.

 

[3393RP]

You can't just up the breaker without installing wiring that is of sufficient ampacity. The breaker is sized to the wire. The wire is what determines the ampacity.

Those breakers are installed on the bus bars of the meter box, they are probably at least 60 or 100A ampacity. I see a main breaker in the panel, what is its rating?

What size wiring did you install in the conduit going to your RV pad? If you are able to get a 30A breaker installed, it will change the wire size requirements. You shouldn't have pulled the wire until this was resolved.

The wiring installed from the panel to the RV pad should take voltage drop into consideration. A 5% voltage drop allowance is sufficient. At 100' #10 AWG would be good. If a 30A breaker is successfully installed, up the wire to #8 AWG.

Just curious, is the temp power pole the only load on the pad mounted transformer in the photo?

 

[Tom-D]

Just follow these instructions.

http://www.myrv.us/Imgs/PDF/50-amp Service.pdf

 

[weilke]

How long are they going to allow you to use a 'temp' pole ?

 

[FastEddieB]

Is somewhat random order...

Yes, the temp pole is right now the only thing attached to the transformer.

I believe the permit is nominally for 1 year. We should have the hangar/barn up by then and ready for the wire to be made permanent.

I think the only breakers in the photo are two 20A. The service requested on the permit was for 100A.

I'll have to check the wire gauge. It was allegedly sized for ultimately carrying 50A, as was the conduit to house it. Only one conduit run had wire pulled.

Nice link weilke. Saved. Thanks.

Headed up to the property today for a quick look. Will report back.

 

[weilke]

Headed up to the property today for a quick look. Will report back.

Take a multimeter and check whether they put the two outlets on the different limbs of the supply. If they did, you could do that monkeybusiness with wiring two 20A outlets to one RV plug. If they are both on the same limb, well then all you have are two 20A outlets ;-)

I still dont get why the utility would restrict a temp pole like that. You get those for construction and there are plenty of tools that require 240V.

 

[FastEddieB]

Stopped by the property.

3x 8GA wire running in what appears to be 1 1/2" grey PVC.

Will be back tomorrow to take some voltage measurements and start wiring things up.

 

[deonb]

So here is an idea - if those plugs are indeed on different legs (you can measure 220V from Live of one to Live of the other), what you can do fairly safely:

a) Put a quick220 on them:


This gives you 240V/20A out on a NEMA 6-20 - and it's protected so you don't have a live male plug dangling if somebody goes and unplugs one side.

Then:
b) Plug in a 220V/110V step down transformer into the Quick220 that's capable of 4000W (not just a 4000W nameplate) - these are generally hardwired ones. That then gives you 110V 36A. With this setup you'll never draw over 20A over those outlets, even if they're somewhat imbalanced.

And when you're done with it next year, sell the setup to one of those "boat" people.

 

[PaulS]

Eddie, you are running a conduit already. Go pull another permit and tell them you want a portable hot tub next to your place and it needs 30 amps and a plug outside. I can't believe there isn't a work around for this, I hate bureaucracy.

 

[FastEddieB]

Spent a couple hours today at the property.

1) 240v between the two hot legs.

2) Finished getting my shed/man cave wired up:

Underground ROMEX from temp pole to shed.

Got one of these RV pedestals in the ground by the conduit and wire:

Will wire that up next time. Good, solid 20A service to the trailer will be a big help regardless.

deonb, that's a pretty creative solution! Let me think about that.

 

[FastEddieB]

Here's an update...

1) An electrician friend did not like the ROMEX underground cable running into the plugs at the temp pole - he said an inspector would frown on that, since ROMEX is not designed to be flexed and has low abrasion resistance. He recommended S00W cable, so that's what I used. Final install at the temp pole:

2) At the RV pedestal, it took a single jumper to bring the 20A service to the 30A receptacle:

Necessary because normally one would have two hot wires feeding the two legs, and for now we only have one.

So, I marked the pedestal thusly:

Have not had a chance to power the RV with it yet. Should have a good solid 20A at the 30A connector, with large gauge wires running from the temp pole to the pedestal. That should be enough to power the air conditioning if nothing else is running, and its easy to throw the breaker for the RV's converter to take that load off as well.

Question...

If someone snuck in at night and swapped a 30A breaker for one of the 20A breakers at the temp pole, would that present a problem? The only "bottleneck" would be the 20A outlet and 20A plug at the temp pole. The rest of the wiring is certainly up to 30A service with no problem.

Thanks for all the input so far!

 

[flyingron]

You need to get a competent electrician out and get fix this disaster.

Type NM (Romex) is **NOT** for outside or underground use, it's neither rated for sunlight nor wet locations (underground even in conduit is always considered wet, for good reason. That's in addition to the the flex issue.

I suspect what he recommended is SOOW (not 500W) CORDAGE (not Cable). That's fine for temporary use.

The receptacle in the bottom picture isn't really right either, but it's pretty darned common in RV hookups. I don't understand why they use those. It's a 7-15R.

Neither the 7-15R or the GFCI duplex 5-20 should be protected with a 30A breaker. They should be 20A.

While it's fine now, when you get to hooking up the RV panel for real, that little jumper between the two screws at the top looks undersized.

 

[FastEddieB]

Thanks. "S00W" is what I typed above, and is what is running where exposed.

The RV panel is as sold by Home Depot with all outlets/breakers in place.

Of course, the 110v 20A outlet will be protected by the 20A breaker in the panel.

I think the jumper is 10GA, but I'll check. What gauge would you recommend?

Here's "behind the scenes" of the pre-wired RV panel:

 

[jsstevens]

Thanks. "S00W" is what I typed above, and is what is not running where exposed.

The RV panel is as sold by Home Depot with all outlets/breakers in place.

Of course, the 110v 20A outlet will be protected by the 20A breaker in the panel.

I think the jumper is 10GA, but I'll check. What gauge would you recommend?

Here's "behind the scenes" of the pre-wired RV panel:

The biggest problem with what you've pictured is the 50A plug is for 220V with the legs 180 degrees out of phase with each other. What you've wired has both legs on the same phase. The 30A plug is OK it just won't handle 30A because you don't have 30A from the temp. I've no idea why anybody who understands electricity would have bothered to add the jumper on the upper left.

 

[flyingron]

It's still not S00W. It's SOOW. O as in the letter between M and P, not 0. And that's a designation of cordage, not cable. I'm confused by your second part.
Cordage is not allowed to substitute for permanent wiring. I assume that the cords are spliced to some approved conductors (THWN for example) inside the LB elbows at the feeding panel.

Depends on how the feeder is sized, but at 50A it should be 8 gauge, not 10.
I hadn't even looked at the plug you'd taped off, but FastEddie is right. That installation is 100% screwed up. You will be overloading the neutral before those breakers trip. I understand that RV's play fast and furious with the rule, but the installation of that hookup panel SHOULD comply with the NEC and it clearly does not.

 

[FastEddieB]

Let me go back a bit to what the goal is here.

By design, everything here is temporary. Once we get our hangar built, an electrical contactor will run power from our transformer to the hangar, then back to our RV pedestals. That wiring will definitely support 30A, and we're debating 50A just in case we have visitors with a larger RV. This should all happen over the next year or so.

The short-term goal is to get as much amperage to our RV as our inspected and approved temp pole allows. 20A should handle our air conditioner, but not much else. Which would be OK, but it would be nice to have capacity for occasional excursions just above 20A.

I'll stop there, but want to address a specific post separately.

 

[FastEddieB]

I've no idea why anybody who understands electricity would have bothered to add the jumper on the upper left.

I'm not sure you meant that to be condescending in the above, but it's easy to read it that way.

The pedestal is set up to take two hot wires. BOTH would run to the 50A receptacle, if it were to be utilized. But for now we only ran one hot lead.

Normally, one hot lead would feed the 20A outlet, the other would feed the 30A outlet and both would feed the 50A outlet. I just wanted the single hot lead to feed either the 20A or the 30A. Power out would be the same, but it would allow me to plug our trailer's plug directly into the 30A outlet, forgoing an adapter plug to the 20A outlet. That's the reasoning behind the jumper.

 

[weilke]

A 'temporary' fire is still a fire. A 'temporary' electrocution is usually permanent.

Find an electrician.

 

[AKBill]

Just wondering if you know for sure what the current draw is with the AC and microwave running in the RV. Not hard to determine with the proper test equipment.

 

[FastEddieB]

Just wondering if you know for sure what the current draw is with the AC and microwave running in the RV. Not hard to determine with the proper test equipment.

This should be a close approximation:

I was mainly warned about the voltage drop from a long extension cord plugged into a 15A circuit damaging the air conditioner.

BTW, our air conditioner is only 13,500 BTU.