Installing 30/50 Amp Outlet Box

[emm-dee]

Questions for the electrical gurus here.

Finalizing the installation of my "RV Carport" next week and getting ready to run the electrical power. I plan on a Connecticut Electric box similar to the ones found at most campgrounds. Has 20, 30 and 50 amp outlets. Connecticut-Electric Outdoor Power Outlet, 120/240V, 80A CESMPSC75GRHR | Zoro.com

The distance from the 200 amp service panel in my barn to the carport will be 90 feet. I discovered that six gauge three conductor with ground wire is really expensive ($200 range). I can get a 100 foot roll of two conductor with ground from a local source for less than $50, and I already have a 100 foot roll of a single six gauge wire.

My question is is it acceptable to use the two conductor wire for the two 50 amp "hot" connections, the ground wire in the 6/2 wg for ground and then use the single six gauge wire for neutral. The wires will be run through PVC conduit and buried about 18 inches. Even though the wires are rated "buried" I prefer to use the conduit.

[hammer55]

# 6 is good for sixty amps, what are you planning to do, tap for the 30 amp. and the 20 amp, you have to plan for all three, if you plan on using any of the two together,,, other wise you have to run enough amperage for all three amperage's combined, depends what you are planning

[caper]

For a 90 foot run 6 gauge wire is too small. At 90 feet you will have a 3.6 voltage drop. You should be using 1/0 or 2/0 wire. When I wired the 27 site at the CG I used single 2/0 wire.

[hammer55]

if you use # 6 wire depends on how you are using it you can use it and have:

1 conductors per phase utilizing a #6 Copper conductor will limit the voltage drop to 1.81% or less when supplying 50.0 amps for 90 feet on a 220 volt system.

70.0 Amps Rated ampacity of selected conductor (but only good for 60 amps when connected to a breaker)
0.2957 Ohms Resistance (Ohms per 1000 feet)
0.048 Ohms Reactance (Ohms per 1000 feet)
6.6000000000000005 volts maximum allowable voltage drop at 3%
3.1. Actual voltage drop loss at 1.41% for the circuit
0.9 Power Factor

but I would use #4 wire myself and have: using a tap rule, utilizing all three receptacles, but that's just me !!!

1 conductors per phase utilizing a #1 Copper conductor will limit the voltage drop to 1.22% or less when supplying 100.0 amps for 90 feet on a 220 volt system.

[emm-dee]

I thank all of y'all for the comments. I notice several mentions of 220 volt. When I originally talked to a county building inspector I asked for the requirement for running the connection for a 120 volts per leg and was told I needed 6/3 (with ground) wire. I didn't ask if I could use four individual six gauge wires (two "hot" wires, one neutral and one ground).

What are the differences between 50 amp 120 volt and 50 amp 220 volt?

[fonzie]

Here is a good link to RV electrical......

RV Electrical Systems

[hammer55]

my MH takes a 50 amp 220, or I can use a 30 120, 50 amp uses a 2 pole breaker, and utilizes two poles of 120 using a neutral and a ground from the service, a 120 uses a single pole breaker utilizing a single run of 120 volts from the service with a neutral and a ground, not sure if anyone uses a 50 amp single pole for a MH or a trailer (fifth wheel) but could be, and yes you can use your wire, if it were me I would use the separate run of wire as a ground or neutral, I would also take the sheathing off of the wires in the cable, but that's me

Originally Posted by emm-dee

I thank all of y'all for the comments. I notice several mentions of 220 volt. When I originally talked to a county building inspector I asked for the requirement for running the connection for a 120 volts per leg and was told I needed 6/3 (with ground) wire. I didn't ask if I could use four individual six gauge wires (two "hot" wires, one neutral and one ground).

What are the differences between 50 amp 120 volt and 50 amp 220 volt?

[Bama Rambler]

The difference between 50 amp 120 volt and 50 amp 240 volt is really just another wire and a double pole breaker instead of a single pole one.

In order to get the full potential of the pedestal (80 amps), you'll need to run #4 copper.

Having said that, since you're using it at home you may not need all 80 amps. If you just want 50 amps you can use the #6 copper and it's fine to use the 2/C w/gnd cable and an extra conductor for the neutral in the conduit. Just be sure that each conductor is clearly marked on each end.

[Harkerr]

For most rigs you can get by with 30 amp 120 volt. I only need 50 amp to run both air conditioners at the same time.

[Ke5rbd]

Will work same as if all in same cover. Make sure polarity on 30 amp is correct

[mikebecker80]

I ran a 10/3 to my 50 amp plug (only 20 feet), and put a 30 amp breaker on it. Just use for battery keeping battery charged.

[Swampy]

emm-dee,
Since you are going to pull it in conduit any way, save yourself some $ and buy the individual wires They will pull much easier than a full USE flat cable. I would go with different color wires Black Hot #1, Red Hot #2, White Neutral, Green Ground. Use stranded wire for ease of pulling and bending and use some liquid dish washing soap ahead of the wire before starting the wire pull. Keep the number of conduit bends to no more than a total of 270 degrees and you should be able to make the pull by hand, else you will need a mechanical pulling assist tool or block & tackle or winch.

I design street lighting systems and power cable installations as a Lead Engineer for the local utility. I've been doing this work for over 35 years and believe me you can pull cable much farther than you think. Good luck on the installation!

Jim Knoch

[LLVanB]

Why do you think you need 50, 30 & 20 amp receptacles? If you want 50 amp in order to run both AC units then just install a 50 amp receptable and save yourself some money. I would think you could get by with #6 -3 w/g. Note you will need 6-3 w/g to meet codes and get both 120V legs. Don't skimp on this! I am an electrical power engineer...

[emm-dee]

Originally Posted by LLVanB

Why do you think you need 50, 30 & 20 amp receptacles? If you want 50 amp in order to run both AC units then just install a 50 amp receptable and save yourself some money. I would think you could get by with #6 -3 w/g. Note you will need 6-3 w/g to meet codes and get both 120V legs. Don't skimp on this! I am an electrical power engineer...

Don't need the 50 amp at this time but if I decide to get a new RV later it might have a 50 amp setup. The cost only goes up about $35. Since the building I'm putting up is 20 feet wide there will be plenty of room to park the truck next to the trailer and and having the 20 amp receptacle already installed in the box it will be available for stuff like vacuuming the truck, battery charger, etc.

[Too Tall]

Here's a wire size calculator. May help you decide.

Wire Resistance and Voltage Drop Calculator

[boondocking]

Originally Posted by Too Tall

Here's a wire size calculator. May help you decide.

Wire Resistance and Voltage Drop Calculator

I don't think that link will help to much, the OP is running line voltage, not DC.

[Too Tall]

thanks boondocking, I used it the other night to buy some battery wire but didn't realize it was DC only. Good catch, never mind.

[hammer55]

usually I do not worry about voltage drop until the distance is 500 foot or more, and if I was doing it for my own personal use then I would do what I wanted to do as long as it was protected, running #6 wire would be OK, as long as I did not go over amperage on the usage end, 60 amps is enough to run all three as long as you use it wisely, and you could also protect is with a 40 0r 50 amp breaker to make sure it is protected, and use a tap to supply all three receptacles, ie: duplex, 30amp, 50amp, that is just for my own usage, of coarse if you ever sold it (the property) you could just remove the duplex and thirty amp and just leave the fifty, or vice-a-versa,,, jmht

[WolfWhistle]

There are many but I use this one:

Voltage Drop Calculator

Remember the distance is there and back and its 120 vac (or the exact if you know it) not 240.
WW

[Karl4Cat]

One thing in this thread that people are a little confused about is the 50 amp RV outlet. It is indeed a 240V. There is no such thing as an RV 4 wire 50 amp 120V plug. So, if your RV has a 50 amp service, your RV connects to a 240V outlet. There is no difference between it and say a grounded range plug in your kitchen. When the 240 volt hits your RV's breaker/fuse panel it splits into two phases just like in your home and half your circuits pull off one phase and half pull off the other since they are all 120V. For more info, photos, and diagrams go to: http://www.myrv.us/electric/ and click on the 50 amp link in the upper left.

Now in an outlet like the OP wants to install with a 30 amp and 20 amp plugs as well, they only pull off a single phase. Only the 50 amp outlet will get both phases. The good thing about these CE panels is they come with all three outlets pre-wired so all you have to do is hook up your wire to the main input lugs and it's done.

As to the run, I have 200 feet from my house to my RV pad. I used #6 and have no voltage drop issues. I can run all three ac's at once and not go below 117 volts on either phase. I also would have no issue using 6/2 and a separate neutral as the OP was wanting to do.

One last thing for the OP. If you haven't already ordered the CE box from Zoro, Amazon has a lower priced alternative that is a touch better quality from Siemens. It would save you $37...

http://www.amazon.com/Siemens-TL137U...=siemens+talon