Wiring a 50 amp 120v rv service

[Zed254]

You are correct for smaller rv's in the 30 amp size. In this case its a 36' 3 slideout land yacht!! They are still 120v but fed by 2 legs instead of 1 for a 50 amp supply..

If camper is wired for 240 volts you will need to supply 240 volt: 2 legs of 120 volts. A 240 volt camper will be similar to a house in that the 120 volt legs are approximately balanced (amps). I would wire it up 4 wire, 6/4 SOOW cable, MEP802 selector switch on 120/240. You will get 26 amps and need to learn to manage the load.....or get a bigger generator. The 6/4 SOOW will be large enough cable in case you decide to buy a smaller camper that only needs the single 120 volt leg.

 

[98G]

If camper is wired for 240 volts you will need to supply 240 volt: 2 legs of 120 volts. A 240 volt camper will be similar to a house in that the 120 volt legs are approximately balanced (amps). I would wire it up 4 wire, 6/4 SOOW cable, MEP802 selector switch on 120/240. You will get 26 amps and need to learn to manage the load.....or get a bigger generator. The 6/4 SOOW will be large enough cable in case you decide to buy a smaller camper that only needs the single 120 volt leg.

I don't disagree with any of this. Let me paraphrase and emphasize some things you didn't. Correct any misconception I have:

Feed the RV 26amps of 240v. The RV will split it out to 52amps of 120v and will do a better job balancing it than we can.

The 6/4 cable is good, and probably overkill for 26amps of 240v. Overkill is good, because if you ever step down to 120v on it, the amperage and thus the heat will double.

 

[LittleBill]

I don't disagree with any of this. Let me paraphrase and emphasize some things you didn't. Correct any misconception I have:

Feed the RV 26amps of 240v. The RV will split it out to 52amps of 120v and will do a better job balancing it than we can.

The 6/4 cable is good, and probably overkill for 26amps of 240v. Overkill is good, because if you ever step down to 120v on it, the amperage and thus the heat will double.

rv won't split anything out, load balancing is done by breaker per phase, so if there is an air conditioner and a microwave on the same phase, he risks overloading only 1 side of the generator.

for the best load balance and NOT requiring 240v in the rv, the generator should be run in 120v mode, and l1 and l2 should be combined to l3 off the generator, this will allow 52 amps to flow down either side of the rv distribution box, and balancing will not be required.

 

[Ranger Danger]

Wow! Now I'm really confused!!

Sent from my SM-G930V using Tapatalk

 

[Triple Jim]

Edit: Upon further reading, my post may or may not have applied, and I didn't want to confuse the issue even more. Ranger Danger should post the manual for his RV where it explains the electrical system, and maybe confusion can be cleared up.

 

[Ranger Danger]

I believe 50a 120 is normal for RVs these days. They're not wired for 240 at all, everything just runs on one 120v 50a input. An 002A has a setting for 120v 50a, and I assume and 802A does also, so if I understand this thread correctly, it should be perfectly OK for Ranger Danger to run his RV this way. #6 is good for 50 amps, so there wouldn't be any need to double up the wires, but he could. 3-wires is all that's needed for this. The only thing confusing to me is the 4-pin receptacle in the original post.

Please elaborate. Where should these 3 wires be connected? What setting should the genny be set on, 120 or 120/240? I don't see a 50 amp setting.

 

[Triple Jim]

Please see my edited post that's no longer what you quoted.

 

[LittleBill]

Please elaborate. Where should these 3 wires be connected? What setting should the genny be set on, 120 or 120/240? I don't see a 50 amp setting.

Ranger,

please read the post a couple up that i wrote. i explained it correctly, Triple is incorrect. i gave you the connections you needed.

 

[Ranger Danger]

Edit: Upon further reading, my post may or may not have applied, and I didn't want to confuse the issue even more. Ranger Danger should post the manual for his RV where it explains the electrical system, and maybe confusion can be cleared up.

The manual does not cover the electrical system to the point that is required to answer the question. The manufacturer does not want the average knucklhead messing with the inner workings of the electrical system.

 

[uniquify]

Ranger Danger should post the manual for his RV where it explains the electrical system, and maybe confusion can be cleared up.

A picture of the RV's panel or it's factory power cord & plug (if it has one) would help immensely. Without more info, we can't be sure we're giving appropriate suggestions.

 

[kloppk]

Keep in mind that if one runs the 802 in 120 v mode to get the 52 amps and connecting the trailers L1 & L2 together the Neutral wiring from the generator all the way to the RV breaker panel must be capable of handling the 52 amps.

Normally when feeding 240 single phase from the 802 (L1 & L2 separated) the neutral line only carries up to 26 amps. This occurs when 1 leg is fully loaded and the other leg has zero load. When both legs are fully loaded the Neutral has zero current. (Assuming 1.0 PF loads)

When connecting L1 & L2 together the neutral has to carry up to 52 amps as opposed to the 26 amps when L1 & L2 are normally separated.
Would hate to see you burn up your trailer should the trailers Neutral not be rated to carry 52 amps.

 

[tobyS]

Then do this....use an ohmmeter to see if L1 and L2 on the camper distribution box are connected. If they are connected, you have straight 120v and it can only be plugged into a 120v source. If they are open, you could have two seperate circuits that allow for connection to your 240 home connection (2 x 120) but could be jumpered together as long as the neutral can handle the full load (NEVER hook it up to your home without removing the jumper....a dead short). If open, you should be able to use the 240 single phase....just like your home wiring....2 hot and one neutral.

Take a photo of the open distribution box.

Buy a current transformer and meter to monitor your loading and turn on one thing at a time to see what can be ran together and what can't. Buying a larger generator may get you the ability to operate many things at the same time, but you are going to pay for it in initial cost and fuel cost.

Your 6 wire is okay for the 52a....maybe not at 100% duty cycle... a load meter would help.

 

[Ranger Danger]

I have been powering the RV with a Yamaha EF3000iseb genny up until now. It has a rated max output of 2800 watts and 25 amps plus a 500 watt 10 second boost for larger draw items. I have it connected to the RV with a 10 gauge power cord 100 feet long. It works ok with some power management, for all but the a/c. I just cant imagine that the MEP-802A will not be enough genny to run this RV!! Its literally double the output of my current genny.


Edit: The Rv has 2 120 feeds. I have them jumped together on the power cord running from my Yamaha.

 

[LittleBill]

I have been powering the RV with a Yamaha EF3000iseb genny up until now. It has a rated max output of 2800 watts and 25 amps plus a 500 watt 10 second boost for larger draw items. I have it connected to the RV with a 10 gauge power cord 100 feet long. It works ok with some power management, for all but the a/c. I just cant imagine that the MEP-802A will not be enough genny to run this RV!! Its literally double the output of my current genny.


Edit: The Rv has 2 120 feeds. I have them jumped together on the power cord running from my Yamaha.

View attachment 722185

then change the wiring to 6gauge, and run in 120v on the MEP, and you should be fine

 

[tobyS]

Your #6 wire is plenty to handle it either way.

Why would you not run this as a 240 (L1, L2, N and G) that is just 2 x 120V...like your house? No jumper. If you put the continuity meter on L1 and L2 and get no reading, then it should work fine

Edit: I read back and see the idea of having a single 120v that can handle 52 amps was introduced.

I'll go back to your table of loads to see if you have them broken down by which of the two 120v circuits they are connected. To get reasonable balance, you should have that information.

Edit 2 : No, the table has loads but not which circuit. That is information that would make it possible to do it once and get right. The big thing running 2 of the largest loads from the same circuit at the same time. We can almost assume the camper people were smart enough to keep them seperate. Check continuity for each circuit to confirm it.


Adding the complexity of a jumper to run unbalanced 120 will gain nothing unless the speculation that they are on the same circuit is correct....which I very much doubt is the case. You don't need #6 for 240v, it can be half that size.

You'll have a circuit breaker pop out from the thermal if it is overloaded. Modern circuit breakers are both magnetic (a short) and thermal (overloaded).

Edit 3 : If you want your AC to work best, run a separate 240 to it and get it off the 120.

 

[Ranger Danger]

First off, A big Thank you to everybody for your help and guidance. At times it was confusing but that just forced me to work harder toward an education and a decision. My plan is to run in the 120v/240v 1PH position. I will run appropriately sized wire in a 1 1/4" PVC conduit and hard wire into the sub panel. Then do some power management. The RV was setup for this to begin with and....who am I to mess with it! My hangup was mostly about amps rather than watts. In an A/C config. vs a D/C config. that's backwards. After looking at the watt ratings, I don't think I will be using more than the genny can provide. I will continue to read and ask when needed so please keep the conversation going. RD

 

[LittleBill]

Edit 3 : If you want your AC to work best, run a separate 240 to it and get it off the 120.

Um, what? the AC in a RV is 120v, not 240.

 

[tobyS]

Um, what? the AC in a RV is 120v, not 240.

A lot of them can have 240v or 120.. If it's capable of being changed (like a jumper) and ran on 240v, it would clearly say. I had a large one that was only 120 and it simply had too much line loss to perform very well. After that, I look for the ones that can go either way (given a choice). And hey, go 3 phase to be more efficient. Some mil air conditioners, even window units (I think) are 3 phase 208.

 

[DieselAddict]

Keep us posted on how it goes.

 

[Daybreak]

Howdy,
You have given us some pictures. Now take a picture on the inlet on the RV. The inlet plug will have special little writing on it will then be your course of action. (NEMA xxa-xxxv) The MEP-802A can supply what you need. It will really depend on the RV itself.

OK, what is the RV? make, model, etc... The internet is fantastic in looking things up.

pictures needed,
inlet
breaker panel in RV