Make 50amp using 2-30 amp outlets

[FLYING BUTCH]

I have a splitter that I can run a 30 amp outlet into my 50 amp coach cord. This will only run one of mu three air conditioners. There is another 30 amp outlet available. Can't I run that into the other side of my splitter and then have power for my other air conditioners? I think I remember at one of the classes at a rally that 50 amp is really just two 30 amps. Or did I misunderstand. Appreciate any advise.

Safe travels everyone

[clyon51]

Originally Posted by FLYING BUTCH

I have a splitter that I can run a 30 amp outlet into my 50 amp coach cord. This will only run one of mu three air conditioners. There is another 30 amp outlet available. Can't I run that into the other side of my splitter and then have power for my other air conditioners? I think I remember at one of the classes at a rally that 50 amp is really just two 30 amps. Or did I misunderstand. Appreciate any advise.

Safe travels everyone

Is this "splitter" a commercially made adapter you purchased, or something you made?

If this adapter has a 50a female receptical on one end, then splits to 2 cords and two 30a male plugs, then yes, if the pedistal has two 30a outlets, you plug them in. Now you have 30a on both legs or a total of 60a available to the coach.

In a normal 50a outlet, you have 2 legs at 50a each for a total of 100a. Does this answer your question?

[RustyJC]

Originally Posted by FLYING BUTCH

I think I remember at one of the classes at a rally that 50 amp is really just two 30 amps. Or did I misunderstand.

Yup, you misunderstood. 50 amp 120/240VAC RV service consists of 2 each 50 amp hot legs wired 180 degrees out of phase for a total ampacity between the two hot legs of 100 amps, or 12000 watts. 2 30 amp circuits would provide a total ampacity of 60 amps (assuming that they are independent 30 amp circuits), or 7200 watts.

Rusty

[jamesrxx951]

Originally Posted by RustyJC

Yup, you misunderstood. 50 amp 120/240VAC RV service consists of 2 each 50 amp hot legs wired 180 degrees out of phase for a total ampacity between the two hot legs of 100 amps, or 12000 watts. 2 30 amp circuits would provide a total ampacity of 60 amps (assuming that they are independent 30 amp circuits), or 7200 watts.

Rusty

Something I just recently learned is that some motorhomes and travel trailers have appliances that run off of 240 (2 120V legs phased 180 apart just like a stick home). So, if both 30 amp receptacles are not 180 apart (phase), the appliances will not work.

[RustyJC]

Originally Posted by jamesrxx951

Something I just recently learned is that some motorhomes and travel trailers have appliances that run off of 240 (2 120V legs phased 180 apart just like a stick home). So, if both 30 amp receptacles are not 180 apart (phase), the appliances will not work.

There are a very few super high end RVs that use 240VAC for cooktops, dryers and other appliances. Any RV that is ever intended to see a variety of campgrounds (i.e., not just the "resorts") without having to run the internal generator will not require 240VAC service as the chances are great that, somewhere along the line, they're going to find themselves in a campsite that has 30 amp service (no 50 amp). Therefore, most 50 amp rigs such as mine don't use the 240VAC capabilities that are present in correctly wired 50 amp service.

That being said, however, it's critical that the 240VAC (not 0VAC) is present between L1 and L2 where 50 amp service is provided to avoid overloading the neutral conductor in the RV's shore power cord.

Rusty

[wa8yxm]

The standard "Dogbone" adapter feeds BOTH sides of your fifty amp plug but you still are limited to one A/C. (Two is more than the breaker (30 amp) can carry)

There is a device sometimes called a "Cheater box" has two 30 amp plugs and one fifty amp outlet, on this device one plug feeds one leg, the other plug feeds the other, it is normally shipped with a 15 amp adapter so you can plug into both the 30 amp and the 15/20 amp outlet on a pedistal and trip the GFCI (in modern parks the 15/20 amp outlet has to be GFCI (some older parks may still have non-GFCI grandfathered outlets) and if the cheater box does NOT blow the GFCI, it is defective.

It will, however, work on a pair of 30 amps. so long as they are NOT GFCI (I have been in two places where they are).

It will trip a GFCI 100% of the time less the GFCI is bad.

I have one of those boxes by the way, when they work they are great.

I also modified my RV.. Since I do not have an Energy managemebnt system I did it like this.

Original

Breaker box-20 amp breaker---wire to rear air conditioner

Above breaker----female end of extension cord
Male end of same cord (12ga by the way)--Wire to AC

Now, for safety I should put a 2nd 20 amp breaker in the junction box where the male cord hooks to the romex but....

I trust the park on that.

Now the cord (Plug and outlet end) are in an exterior compartment, I pull the plug, plug my wi-fi modem into the outlet (I mean it needs power after all) and plug a 12ga extension cord into the park and plug the A/C into that.

[bartlettj]

The neutral conductor on the 50 amp cord is sized the same as the L1 and L2 conductors. If you hook it up to two 30's that are in phase, you will be putting 60A of return current on that neutral and you will burn it out. Then you will have a safety hazard and may destroy your AC units. Neutral conductors do not have circuit breaker protection.

[FLYING BUTCH]

I'm not good at electrical. What I have , bought at camping world, is a splitter that my 50 cord from the coach plugs into. That splits into two 30 amp cords. They marked which cord will charge one side of my coaches system to keep batteries charged and run the coaches 120 amp things. It will run my middle air conditioner. I am going to a park for a week. I rented two 30 amp sites. I want to run two separate 30 amp cords into my splitter so I can run all 3 air conditioners. Will this work? Thanks everyone for your assistance with an electrical dummy!

[Ramets]

I have thought of this many times. But my problem is when someone starts using electrical jargon my eyes glaze over since I don't speak the language. I guess what I'm trying to say is, will the 2 30amp's work as a 50amp on a wish bone type hook-up?

[BCooke]

Originally Posted by RustyJC

Yup, you misunderstood. 50 amp 120/240VAC RV service consists of 2 each 50 amp hot legs wired 180 degrees out of phase for a total ampacity between the two hot legs of 100 amps, or 12000 watts. 2 30 amp circuits would provide a total ampacity of 60 amps (assuming that they are independent 30 amp circuits), or 7200 watts.

Rusty

Hope you were stating 180 for clarity.

[BCooke]

Originally Posted by Ramets

I have thought of this many times. But my problem is when someone starts using electrical jargon my eyes glaze over since I don't speak the language. I guess what I'm trying to say is, will the 2 30amp's work as a 50amp on a wish bone type hook-up?

The Y will give you 2 30 amp connections where as a normal 50 amp plug gives you 2 50 amp connections. It will function the same but if you run your A/C and you have a hair dryer or coffee pot you may still trip.

[BFlinn181]

RV 50 amp service is two 120 v 50 amps 2 X 120 v X 50 a = 12,000 watts
RV 30 amp service is one 120 v 30 amps 120 v X 30 a = 3,600 watts

Even with two 30 amp lines feeding your RV, it's still only 7,200 watts compared to 12,000 w from 50 amp service, or 60% of 50 amp service.

[RustyJC]

Originally Posted by BCooke

Hope you were stating 180 for clarity.

I guess I don't understand your comment. The two 120VAC hot legs (measured to N) of a split-phase 120/240VAC service are 180 degrees out of phase with each other. That's what produces the 240VAC across L1 and L2 and what makes the neutral currents subtractive instead of additive. See the split phase diagram of a center tap neutral transformer used to provide this split phase service (3rd diagram from the left) HERE.

Rusty

[BCooke]

OK.
I am working on an assumption, so my basis could be off.
Assumption:
Due to the size of the services required, the campground is supplied with three phase service as commercial entities are.
From that of course, three phase has a 120 deg separation.

Yes/no ?

Side note: I do not trust that they have used separate legs for separate outlets. Measure voltage across the 2 hot legs to make sure you have separate phases so as not to over load the neutral if they are not.