Need advice on adding 50 amps plug for RV

[keouchao]

Hi,

I am planning to install an outdoor 50 amps plug in my backyard for RV. Following is my plan, and I would like to get an advice on any issue it may have.

The main wire panel is in the basement at front of the house, I am planning to install the plug on a post 30 feet from the back of the house. I will install a 50 amps GFCI breaker, running #6 UF-B wire from the panel to the back of the house (about 50 ft). Drill 1 inch hole for the wire to get out to the back of the house.

From the back of the house, install a junction box (about 3 feet above ground outside the house), it will connect IMC conduit downward, going 6 inches underground. There is one 90 degrees turns for the conduit; plus two 90 degrees turn for enter / exit the ground level. The 50 amps plug is a 14-50R receptacle inside outdoor enclosure mounted on 4x4 post 3 feet above ground.

I have couple questions - the total wiring length is 80 ft, 50 ft indoor, 30 ft outdoor inside conduit.
- does a 3/4 inch conduit works ? can I fish #6 wire through 30 ft conduit with 3 turns ?
- is it better to have run 30 ft wire outdoor, and 50 ft wire indoor and connect it at junction box or just a single 80 ft wire from panel to plus ?

Thanks for any advice.

 

[nsula_country]

If in doubt upsize to 1" but 3/4" will work.

I just pushed 4, #6 and a #10 in 1" EMT last week with 3 90*.

Don't think you need a GFCI for RV drop. Could be wrong. Have never seen a GFCI at ANY campground except for 20A convenience receptacle.

CT

 

[wyliesdiesels]

Why are you using UF-b indoors? Why not NM-b?

Can conduit be ran for the indoor portions? If so i would just run #6 THWN for the whole length and skip the splices and hassle of UF-b especially in conduit...

 

[theoldwizard1]

You are going to need larger conduit than 3/4" especially if you are going to run UF-B.

The other thing to consider is cost ! Aluminum, although much larger diameter, is much cheaper. I am not the expert on this so someone else will have to say it I am in correct, but you could use 2-2-2-4 aluminum SER inside the house and then switch to 2-2-2-4 MHF aluminum in an appropriately sized junction box (either just inside or or outside). This will be MUCH CHEAPER !

I am guessing, but if it was me, for the 30' I would use 2" PVC conduit unless there is a real reason for IMC.

 

[theoldwizard1]

Can conduit be ran for the indoor portions? If so i would just run #6 THWN for the whole length and skip the splices...

If you can run the conduit indoor, you could use 2-2-2-4 MHF the whole way. Cheaper than 3 #6 and a #4 copper all though those individual conductors would probably be easier to pull.

 

[nsula_country]

You are going to need larger conduit than 3/4" especially if you are going to run UF-B.

The other thing to consider is cost ! Aluminum, although much larger diameter, is much cheaper. I am not the expert on this so someone else will have to say it I am in correct, but you could use 2-2-2-4 aluminum SER inside the house and then switch to 2-2-2-4 MHF aluminum in an appropriately sized junction box (either just inside or or outside). This will be MUCH CHEAPER !

I am guessing, but if it was me, for the 30' I would use 2" PVC conduit unless there is a real reason for IMC.

150' of #6 Cu is affordable. I bought a 500' spool few months ago for about $200 ish. Recently bought 130' cut.

Supply house can pull it off of a big *** spool by the foot (thousands of feet).

#6 Cu will be more cost effective over Al than the upsize to 2" conduit.

CT

 

[sberry]

You need to bury underground to legal depth. I might be tempted to go uf b all the way, simply sleeve it up and down where I had to or shield it along the way. I avoid splices where I can.

 

[mike93lx]

6" isn't deep enough. IIRC, 18" if conduit, 24" if direct burial

UF ***** to deal with. I would only use it if there wasn't an alternative. If you are running conduit, there is absolutely no reason to use it

 

[sberry]

No problem if it's piped all the way.

 

[mm08822]

6" isn't deep enough. IIRC, 18" if conduit, 24" if direct burial

UF ***** to deal with. I would only use it if there wasn't an alternative. If you are running conduit, there is absolutely no reason to use it

6" is minimum for imc and grc without vehicle traffic over it. I would go deeper myself.

18" is pvc minimum.

 

[mike93lx]

6" is minimum for imc and grc without vehicle traffic over it. I would go deeper myself.

18" is pvc minimum.

noted, thanks for the correction.

I would go deeper as well, unless the soil conditions made it too challenging.

 

[wyliesdiesels]

If you can run the conduit indoor, you could use 2-2-2-4 MHF the whole way. Cheaper than 3 #6 and a #4 copper all though those individual conductors would probably be easier to pull.

The ground only needs to be #10.

 

[95vette]

Hello, Didn't see it mentioned but it must be four conductor for RV plug.

 

[walta]

The 240V GFIC breaker will not work for 120 volt loads in a camper.

Walta

 

[mm08822]

The 240V GFIC breaker will not work for 120 volt loads in a camper.

Walta

He would have to use a 120/240v rated gfci breaker. Both hots and neutral are monitored.

 

[dcg9381]

I don't think these things are typically GFCI either, but I stand to be corrected. I know that spas are 50A GFCI, but haven't seen an RV connection done that way.

The 240V GFIC breaker will not work for 120 volt loads in a camper.

In terms of not working for 120V loads in a camper - bigger campers are 240V @ 50A and split sides internally on their own load panel.

Alternately, people step down these 240V @ 50A connections with an adapter, but it is not overload-protected.

There's a great box on amazon - really a subpanel, that has 50A, 30A, 20A (GFCI protected) for about $130 on amazon. Outdoor OK. Look for Siemens TL137US. Comes with 3 breakers. I've put in 3 of these panels - I love them for the price and the flexibility of what you get.

I run 6GA copper NM-B (romex) in 3/4" conduit all the time for interior runs under 50'. I wouldn't recommend it for long distances - definitely do 1". You can get it thru a 3/4" liquid tight connector at the tail, but it's a real pain.

 

[Bert_]

This doesn't need a GFCI at all.

I'd be looking at #4 al xhhw or direct bury.
**Actually #6 AL xhhw or direct bury is good for 50A assuming your terminations are rated 75*C.

I would hardly ever consider using #6 uf. Not only because it's expensive but mostly because it's a pain to deal with.

 

[sberry]

At that distance I might be looking to save a little money on wire too. I will agree about some adapters, they do make a 50/30 that is legal due to the fact there is further ocpd on those circuits. On 20 got to add it.

 

[alfredeneuman]

A 120/240V GFI on the receptacle would take down all the power to the whole RV any time it detected a ground fault.
I wouldn't want that

 

[mike93lx]

I run 6GA copper NM-B (romex) in 3/4" conduit all the time for interior runs under 50'. I wouldn't recommend it for long distances - definitely do 1". You can get it thru a 3/4" liquid tight connector at the tail, but it's a real pain.

why would you run NM-B over THHN if it is going in conduit?

 

[mm08822]

A 120/240V GFI on the receptacle would take down all the power to the whole RV any time it detected a ground fault.
I wouldn't want that

Yeah, that would get old quickly. Point of use within the rv is better, easier to isolate.

 

[nsula_country]

why would you run NM-B over THHN if it is going in conduit?

Trying to figure this one out too. Thought OP was running conduit the whole run.

I reinforce the 18" conduit, 24" direct bury comments.

I also reinforce that you DO NOT NEED a 2 pole GFCI and if you use one, you will have problems.

CT

 

[dcg9381]

why would you run NM-B over THHN if it is going in conduit?

In my circumstance, I have some wood framed walls, so I use it as romex in some places. I put it in conduit (PVC) where we aren't framed or if it's used "outdoors".

I agree that if you're 100% in conduit THHN is easier and perhaps less expensive.

I don't agree (another poster) that using aluminum is the way to go on a 50A circuit - but it IS less expensive. For me, it's not worth the hassle of the added diameter.

 

[Bert_]

Sometimes I would agree but OP wants to use 6-3 uf. Some #4 or #6 direct bury aluminum would fit in smaller conduit and be easier to work with. To me the reduced cost would not be the main reason.

 

[theoldwizard1]

At that distance I might be looking to save a little money on wire too. I will agree about some adapters, they do make a 50/30 that is legal due to the fact there is further ocpd on those circuits. On 20 got to add it.

Wiring a 30A RV outlet would save a TON of $$ ! The difference in price of 10/2 NM-B vs 10/2 UF-B is only about $10-$20, less than buying a weatherproof junction box and you should be able to pull it through 1" conduit.

Usually, the only reason an RV has 50 service is because it has TWO A/C units ! Of course RV manufacturers never publish a wiring diagram so you don't know which outlets are on this leg, but with some patience you can figure that out. If make your own adapter, you could connect L1 and L2 as long as you do NOT turn on both A/C units.

 

[Falcon67]

Wiring a 30A RV outlet would save a TON of $$ ! The difference in price of 10/2 NM-B vs 10/2 UF-B is only about $10-$20, less than buying a weatherproof junction box and you should be able to pull it through 1" conduit.

Usually, the only reason an RV has 50 service is because it has TWO A/C units ! Of course RV manufacturers never publish a wiring diagram so you don't know which outlets are on this leg, but with some patience you can figure that out. If make your own adapter, you could connect L1 and L2 as long as you do NOT turn on both A/C units.

I did not use a GFCI anything on the run to our "RV". (RV = 34' enclosed race trailer with bath package). There are GFCI plugs in the trailer where required. So no need. I also ran only 30A worth of wire because unless we're in a disaster and living in the trailer running on the generator, it doesn't need or pull 50A. The 15K AC pulls 13A and the rest is lighting. I only need the AC and lights for basic maintenance between races.

"Usually, the only reason an RV has 50 service is because it has TWO A/C units ! "

Not so - it damn sure needs 240V power. You need to balance loads in an RV, same as a house. Our trailer has AC, microwave, fans, fridge, portable toaster oven along with things like air compressor, battery charger, air blower. 30A 120 service would mean having to budget power - don't use the microwave while I'm charging the car battery, etc. So yea - I need "50A service" 240v. For a "real" RV, I would run the full 50A 240 service because you just might be livin' in that van down by the river.

 

[sberry]

I would run 50 also, I was just making comment that there are SOME legal adapters in reference to another post.

 

[keouchao]

Thanks all for the helpful information, more details -

- GFCI breaker,
Is the NEC code requires it for all outdoor wiring? or this is an exception

- Conduit, Wiring
There are exist wiring holes in my basement joists (20+) that can pass through 6/3 wire, but not a conduit; that is why I do not plan to conduit indoor. For outdoor, lots of rocks under my backyard, minimum digging is my objective (using IMC conduit).

So, considering the comments against UF-B for hard to handle; NM-B indoor, THHN outdoor (easiest to pull through conduit). and my junction box will need to be indoor not outside.

 

[Captain Spaulding]

- GFCI breaker,
Is the NEC code requires it for all outdoor wiring? or this is an exception

For an RV pedestal, only the 120V 20A outlet requires GFCI protection.

 

[dcg9381]

The only case I know for GFCI on >20A circuits is spa/pool service. I stand to be corrected.

The pedestal I mentioned has a GFCI 20A circuit on it.


I have one case in my shop where I want an RV connection at the front, but didn't want to spend the $$ necessary to run 6 GA wire. Instead, I ran 10/3 @ 30A. In that case, I wired it as 30A 240V into a standard RV 50A outlet with a 30A label on it. This is enough to run my welder, I can step it down to a 120V @ 30A RV connection, and it will run both ACs on any RV that has the ACs on opposite sides of the circuit... At least that's the theory.

So, considering the comments against UF-B for hard to handle; NM-B indoor, THHN outdoor (easiest to pull through conduit). and my junction box will need to be indoor not outside.

My comment against would be splicing it in a junction box(es). Looked into the price of insulated tap connectors / polaris connectors? They're between $10-$20 each and you'll need at least 3 per junction.

Can you hang the conduit under the basement joists rather than thru?

 

[teamextreme]

You can also splice #6 using large blue wire nuts at a fraction the cost of the fancy-*** polaris connectors.

 

[nsula_country]

You can also splice #6 using large blue wire nuts at a fraction the cost of the fancy-*** polaris connectors.

Or split bolts...

CT

 

[keouchao]

Or split bolts...

CT

Anyone use this type of terminal block (WECO 327-HDS/04), sorry, can not post a direct link due to low post count... working on it

 

[nsula_country]

Anyone use this type of terminal block (WECO 327-HDS/04), sorry, can not post a direct link due to low post count... working on it

I have used those. If sized properly, will work fine.

If I'm going to use terminal blocks, usually will go with DIN rail and DIN terminals.

CT

 

[keouchao]

150' of #6 Cu is affordable. I bought a 500' spool few months ago for about $200 ish. Recently bought 130' cut.

Supply house can pull it off of a big *** spool by the foot (thousands of feet).

#6 Cu will be more cost effective over Al than the upsize to 2" conduit.

CT

In portland OR, Platt is the one I used; any other supply house I may check. Thanks

 

[Bert_]

#6 Cu will be more cost effective over Al than the upsize to 2" conduit.

CT

2" ! Why would you need 2"? Some #4 or #6 aluminum would pull into 1" just fine...

 

[nsula_country]

2" ! Why would you need 2"? Some #4 or #6 aluminum would pull into 1" just fine...

In post #4 theoldwizard1 suggested Al and 2" conduit.

CT