50 Amp 120/240V Twist Lock Configuration

[Metalman RVer]

We just pulled the trigger on a 2007 Glendale Titanium 5th wheel & being up here in the north will not be taking delivery of the unit for about 2 months or so yet. I would like to start looking into providing shore power for the unit here at home for the unit & plan to supply full 50 amps of power to it.  I have some knowledge in the electrical wiring world with the various plug/receptacle configurations for different voltages/amperages in buildings but not RV's. Is there a standard for the plug/receptacle configuration for 120/240 50amp twist lock in rv's, like a NEMA number (or similar) that identifies them?  I will be using an outdoor rated box to supply the power.

Thanks

 

[SeilerBird]

Here is the plug you want. It is two 110 volt lines, there is no 220 involved. NEMA is 14-50R.

 

[Metalman RVer]

Ok......I see, just the straight blade 50 amp then? I did see a twist lock on the rv, but would that just be in the rv end only?

Are the campgrounds that have 50 amp capacity usually (or always) the 14-50R configuration then?

 

[SeilerBird]

Ok......I see, just the straight blade 50 amp then? I did see a twist lock on the rv, but would that just be in the rv end only?

Are the campgrounds that have 50 amp capacity usually (or always) the 14-50R configuration then?

Here is the twist lock like I have on my RV.

https://www.amazon.com/Power-TechON-RVA4016-Twist-Adapter/dp/B01K0MBYDE/ref=sr_1_2?ie=UTF8&qid=1487024727&sr=8-2&keywords=rv+twist+lock+adapter

All RV parks use the 14-50R for 50 amp and the TT-30R for 30 amp.

 

[grashley]

Yes, you want the 240V connection per normal wiring.  The very first thing the RV does is split that 240V single phase into two separate 120V supply lines.  RV use 120V ONLY.

If you were wiring a 30A circuit for the RV, this is VERY DIFFERENT from household wiring.  While the plug LOOKS similar to a 240V dryer plug, it is in reality simply a heavy duty 120V plug, wired with a 120V hot, neutral and ground.  An RV plugged into a 240V 30A household plug will result in significant damage to 120V appliances.

 

[Metalman RVer]

Ok, thank you for the clarification on the electrical feed requirements.

 

[robertusa123]

Its the same outlet at a 4 prong stove. 50amp.    You can buy a outdoor rv plug incloser at lowes or home depot.  6-3 wire

 

[xrated]

Its the same outlet at a 4 prong stove. 50amp.    You can buy a outdoor rv plug incloser at lowes or home depot.  6-3 wire

Fixed that for ya, ......  6/4 wire.......2 hots, a neutral, and a ground!

 

[Prior member]

I just finished adding a 240 volt, 50 amp panel to my new 30 amp trailer.
I now have two separate supplies and adequate power to add a washer and dryer.
The panel came with a 100 amp main, but I changed it out to a 50.
I also disconnectd my air condition feeder from the 30 amp panel and rerouted it via a junction box to a new single pole 10 volt 20 amp breaker in the new panel.

We can now run the residential refrigerator, the air conditioner, the electric water heater and any electric appliance at the same time with out popping the 30 amp breaker breaker.

jack L

 

[Isaac-1]

Fixed that for ya, ......  6/4 wire.......2 hots, a neutral, and a ground!

The wire may be labeled as 6/3 with ground often simply referred to as 6/3  when talking about NM-B or UF (often called Romex or Outdoor Romex), which actually has 4 conductors, 3 insulated current carrying conductors and a bare ground wire all in an common jacket.  If Romex style wire is code legal for your particular installation is another matter, while once widely used 30-50 years ago there has been a trend in the NEC for years to limit the locations where this style wire is code legal, and is now down to certain types residential installations in locations where the wire is protected.

 

[SeilerBird]

Fixed that for ya, ......  6/4 wire.......2 hots, a neutral, and a ground!

It could either be called 6/3 or 6/4 but 6/3 is technically more correct since the ground wire is not included in most wire descriptions 12/2 has a hot, a neutral and a ground. 12/3 has two hots a neutral and ground.

 

[xrated]

It could either be called 6/3 or 6/4 but 6/3 is technically more correct since the ground wire is not included in most wire descriptions 12/2 has a hot, a neutral and a ground. 12/3 has two hots a neutral and ground.

You are referring to NM-B type cable and/or the UF type.  There is a designation for both 12/2 (you can buy it this way with no ground wire in it) and 12/2 w/ground.  There is also 6/3 (you can buy it this way with no ground wire in it) and 6/3 w/ground.  If the original poster is wiring a service disconnect (fused or breaker style), then the easiest method would be to use one of those two types of wire, which ever is applicable.  If he is making a short run from an existing panel and adding a sub panel, then individual 6 ga. wire (THHN) would most likely be the preferred method).  If he is making up a shore power cord, then obviously he needs the SOOW type cord which is designated 6/4.

My entire purpose/reason for posting my original post is so that the fellow didn't buy a length of wire and end up with one conductor short (missing) in his connection.

 

[robertusa123]

Fixed that for ya, ......  6/4 wire.......2 hots, a neutral, and a ground!

Nope 6-3.  Ground is a given and is not included in the description. 
Aka 14-2.  Hot neutral and ground
6 -3.  2 hots a neutral and a ground

 

[Gary RV_Wizard]

RV use 120V ONLY.

Not really so. Probably 99% of existing RVs use a 50A/240V source as twin 120v, but ultra high end models from Newell, Wanderlodge and the various Prevost conversion brands have utilized 240v for many years. Some newer mid and high end models are now doing the same, offering 240v dryers and electric stoves as optional equipment. I know Tiffin has a 240v dryer option, for example.

 

[xrated]

Check it out for yourself Robert.  Just one of probably thousands .....

http://www.homedepot.com/p/Romex-125-ft-6-3-Black-Stranded-CU-SIMpull-NM-B-W-G-Wire-63950002/202316279

This, also taken as a description bullet with another ad for 6/3....
*Southwire Type UF-B cable is manufactured as a 2 or 3 conductor cable, with or without a ground wire

As I Stated in an earlier post:  The WHOLE purpose for this is/was to keep the original poster from buying the wrong product when he adds his 50A service for the trailer.  I do not know what he knows or doesn't know about electrical stuff, so in an effort to keep him from buying the wrong wire (which usually cannot be returned if it was cut from a large spool at the store), this is why I posted what I posted.

Having been a Journeyman Maint. Electrician since 1980, I've seen a lot of different types of wire/cable/multi-conductor cable, etc.  And for a non electrical person to try and figure it out sometimes, it's very easy to buy the wrong stuff because some guy at Home Depot or Lowes tells you "this" is what you need to do the job.

 

[robertusa123]

Check it out for yourself Robert.  Just one of probably thousands .....

http://www.homedepot.com/p/Romex-125-ft-6-3-Black-Stranded-CU-SIMpull-NM-B-W-G-Wire-63950002/202316279

This, also taken as a description bullet with another ad for 6/3....
*Southwire Type UF-B cable is manufactured as a 2 or 3 conductor cable, with or without a ground wire

As I Stated in an earlier post:  The WHOLE purpose for this is/was to keep the original poster from buying the wrong product when he adds his 50A service for the trailer.  I do not know what he knows or doesn't know about electrical stuff, so in an effort to keep him from buying the wrong wire (which usually cannot be returned if it was cut from a large spool at the store), this is why I posted what I posted.

Having been a Journeyman Maint. Electrician since 1980, I've seen a lot of different types of wire/cable/multi-conductor cable, etc.  And for a non electrical person to try and figure it out sometimes, it's very easy to buy the wrong stuff because some guy at Home Depot or Lowes tells you "this" is what you need to do the job.

Thats stranded rubber cord.  Ake extension cord.  And yes tencley your right.  On rubber cord they count the ground as a conducter.....  But on none Metallic solid wire AKA Romex the ground is not counted as a conducter
I be happy to place a wager on it

 

[Metalman RVer]

Yes, I already have the SOOW or SJOW cord with the rv, so the new addition will be a case of running PVC conduit (with strand wiring inside) or Tek cable to power the new outdoor 50 AMP power Box, which will be 6/3 (2 poles + neutral + ground, ground not counted)  from our existing outdoor panel under our elevated deck to the new receptacle, which will be a distance of about 15'.  I believe you only count the ground if the supply is in chord?

 

[John From Detroit]

The Twist lock is a standard Marinco Marine type normally used on Boats due to it being water tight when properly locked... However it is only used on the RV end of the cord, them puppies are expensive.

For the "Park" end it is a different plug.. I do not know if the one linked to above is it or not.  But it is like the Stove plug

Some folks talk about the 120/240 volt issue.. I saw one person abouve say "it is two 120 volt lines no 240 volt involved"

Very misleading.. It is 120/240/120 volt service EXACTLY THE SAME AS AN ELECTRIC RANGE..  It IS 240 volt, not "two 120 volt lines" but 240 volts divided..  There is a reason for this.  Two of them in fact.

If you run two 120 volt lines, and pay attention to phase (Which side of the 240 volt service) then you wind up with 120 volt side to center (Assumes the round pin is either top or bottom) and 240 volts side to side.

But if you run two 120 volt lines, both on the same leg.. You get 120 volts side to center and since it's A/C and the only thing, if there is anything, in the RV that looks for 240 volts is an energy management system made by Intelletec that sheds loads (that's how it knows you are hooked to 50 amps)..  Everything works.

BUT at FULL LOAD. the neutral is not hauling 50 amps. but 100. this will likely over heat it and may cause all sorts of issues...... Like a visit from a company that still makes house calls...... The Fire Dept.. (Do you know why a group of firefighters are called a Company?)

So it is wired just like a stove with 120 volt side to center but 240 volt across. We just never use the 240 volt. but it's there.  I can measure it.

 

[xrated]

Thats stranded rubber cord.  Ake extension cord.  And yes tencley your right.  On rubber cord they count the ground as a conducter.....  But on none Metallic solid wire AKA Romex the ground is not counted as a conducter
I be happy to place a wager on it

This is NOT rubber cord....
https://www.lowes.com/pd/Southwire-250-ft-10-3-UF-Wire-By-the-Roll/3234088

Scroll down to the description, and open it up.  Fourth "bullet" down and read it.

You can send me a PM for my address for your payment to me!  ;D

And BTW, the link that I posted above that references the wire from Home Depot.....that's NOT rubber cord either!....Just sayin'

 

[xrated]

The Twist lock is a standard Marinco Marine type normally used on Boats due to it being water tight when properly locked... However it is only used on the RV end of the cord, them puppies are expensive.

For the "Park" end it is a different plug.. I do not know if the one linked to above is it or not.  But it is like the Stove plug

Some folks talk about the 120/240 volt issue.. I saw one person abouve say "it is two 120 volt lines no 240 volt involved"

Very misleading.. It is 120/240/120 volt service EXACTLY THE SAME AS AN ELECTRIC RANGE..  It IS 240 volt, not "two 120 volt lines" but 240 volts divided..  There is a reason for this.  Two of them in fact.

If you run two 120 volt lines, and pay attention to phase (Which side of the 240 volt service) then you wind up with 120 volt side to center (Assumes the round pin is either top or bottom) and 240 volts side to side.

But if you run two 120 volt lines, both on the same leg.. You get 120 volts side to center and since it's A/C and the only thing, if there is anything, in the RV that looks for 240 volts is an energy management system made by Intelletec that sheds loads (that's how it knows you are hooked to 50 amps)..  Everything works.

BUT at FULL LOAD. the neutral is not hauling 50 amps. but 100. this will likely over heat it and may cause all sorts of issues...... Like a visit from a company that still makes house calls...... The Fire Dept.. (Do you know why a group of firefighters are called a Company?)

So it is wired just like a stove with 120 volt side to center but 240 volt across. We just never use the 240 volt. but it's there.  I can measure it.

That's correct John.  If you would use two 120 volt legs from the same side of the 240 Volt supply, both legs are in phase and the neutral would be trying to carry 100A when fully loaded.  Using the standard 14-50 NEMA plug gives you two 120 volt legs that are 180 degrees out of phase with each other, causing the neutral to carry a maximum of 50A even when pulling the full load of the system.