Community Forums

Houdini52 · 10-15-2010, 09:45 AM

Anyone know if a 30A to 50A Step Up Transformer exists? And... where one would get it?

One of my favorite parks only offers 30A service, which is a problem for my 50A 5th Wheel. I have to turn off items in order to run A/C or Washer/Dryer etc...

Thx, Dale

azloafer · 10-15-2010, 10:02 AM

Quote:

Originally Posted by Houdini52

Anyone know if a 30A to 50A Step Up Transformer exists? And... where one would get it?

One of my favorite parks only offers 30A service, which is a problem for my 50A 5th Wheel. I have to turn off items in order to run A/C or Washer/Dryer etc...

Thx, Dale

I bought a unit from Camping World that was supposed to make 50 amps by plugging one cord into the 30 amp outlet and one into the 20 amp. This was at a park in Bisbee, Arizona. It did not work. I called the company and was told that it will not work in all parks depending on how the park is wired with ground fault interrupters. I returned it to Camping World. I am not sure if this answers your question. Happy travels, Joe

RustyJC · 10-15-2010, 10:19 AM

That's not how transformers work. To oversimplify, both sides of a transformer will have constant wattage (Volts x Amps = Wattage), less transformer losses (OK, actually constant VA for the electrical engineers reading this). Therefore, if you had the input side of a theoretical transformer hooked to a 120 VAC 30 amp supply, you would have a total of 3600 watts available (120 VAC x 30 amps = 3600 watts).

Theoretically, this transformer could have twice the number of windings with a center-tap neutral on the output side which would give you 2 each 120 VAC legs just like true 50 amp service with L1 to L2 reading 240 VAC, but you would only have a total of 15 amps available on the output side (120 x 30 must equal 240 x 15) since the total wattage must be constant. You can't create wattage with a transformer, which you would have to do to get 2 each 120 VAC x 50 amp circuits on the output side.

Sorry....

Rusty

WOODYDEL · 10-15-2010, 10:28 AM

If you find one, I'd like the name of the company so I can invest some money. Well, maybe in some parallel universe this might be possible...

I have a name for the transformer: the SOMETHIN FROM NUTHIN.

Route 66 · 10-15-2010, 10:48 AM

I agree with the others, there is no such thing.

Transformers increase or decrease voltage, not amperage.

Remember, that 50 amp service is actually 2 50 amp circuits for a total of 100 amps, over 3 times the current available from a 30 amp circuit.

BryanL · 10-15-2010, 12:06 PM

re: " Transformers increase or decrease voltage, not amperage." -- whoops. It's watts that stays the same. That means if voltage goes up, amps go down in proportion (and vice versa) so the watts in will equal watts out (neglecting losses).

A 50 amp RV service is a 12,000 watt electrical service. A 30 amp service is a 3600 watt electrical service.

Route 66 · 10-15-2010, 12:31 PM

Quote:

Originally Posted by BryanL

re: " Transformers increase or decrease voltage, not amperage." -- whoops. It's watts that stays the same. That means if voltage goes up, amps go down in proportion (and vice versa) so the watts in will equal watts out (neglecting losses).

A 50 amp RV service is a 12,000 watt electrical service. A 30 amp service is a 3600 watt electrical service.

That's true, but for this discussion, trying to keep it from getting too technical, there is no amperage to be gained by a transformer.

BryanL · 10-15-2010, 12:44 PM

Confusing people with 'too technical' should not be confused with confusing via mistakes and errors, especially in regards to units of measure and what is being measured.

A major purpose of transformers is to swap between voltage and current. That means that they do indeed gain or loose amperage in inverse proportion to voltage.

It is power, as measured in watts, that transformers do not change.

Rick Long · 10-15-2010, 01:21 PM

Dale... the answer is NO there is not one.

azloafer · 10-15-2010, 03:10 PM

It is called a 50 amp RV box adapter. It is sold by camping world and many other outlets. The following is the description from Camping World's ad:

Use your 50-amp power cord in parks without 50-amp service to operate lights and appliances. Two 30-amp plugs on heavy-duty 17"L UL approved cords supply power to a 50-amp receptacle from any combination of two 30-, 20- or 15-amp power receptacles. One 30-amp connection and one 20-15-amp connection (with included adapter) on separate circuits is the ideal situation for running both air conditioners. For providing 20-15 amps on each leg an additional #24493 30-to-15-amp adapter (sold separately) is required. Receptacle is housed in a weather-proof box with flip cover and works best if outlets are on separate circuits. Polarity check of each park receptacle is recommended before use-see #16036 Good Governor

Just go to Camping World or through google and put the title in :
"50 amp RV box adapter"

Oh and I'll be waiting for the apologies!!! I never called it a transformer. I called it a "unit" as I recall. Joe

azloafer · 10-15-2010, 03:47 PM

February 10, 2010
We camp at many places where 30 amp is the only power source available. With this unit I can plug into the 30 and 20 amp service and run everything without any power issues! If you camp at older RV parks with limited 50 amp power available, then this is the Getty-up you want in your bag-O-power tricks! Understand it will NOT work on a GFI protected 20-15 amp outlet. But most places we hit... Don't have GFI outlets at the utility pole so it's never been an issue. I use a "Surge Guard" after plugging into everything, just in case ;o)

By Gordobear
from Sacramento, CA
This product is great!

RustyJC · 10-15-2010, 05:34 PM

The adapter you describe, even if no GFCI is present so that it can work, will not provide 50 amps on each leg of the 50 amp service. It will provide no more than the amperage of each circuit that it's plugged into - for instance, if it's plugged into a 30 amp and a 20 amp shore power outlet, it will provide 30 amps on one leg and 20 amps on the other leg of the "50 amp" service plug since these current outputs are limited by the shore power circuit breakers in the respective circuits.

Maybe that's enough for what you want, but be aware that it's not true 50 amps and won't run everything you could run on true 50 amp service.

Rusty

azloafer · 10-15-2010, 05:47 PM

Quote:

Originally Posted by RustyJC

The adapter you describe, even if no GFCI is present so that it can work, will not provide 50 amps on each leg of the 50 amp service. It will provide no more than the amperage of each circuit that it's plugged into - for instance, if it's plugged into a 30 amp and a 20 amp shore power outlet, it will provide 30 amps on one leg and 20 amps on the other leg of the "50 amp" service plug since these current outputs are limited by the shore power circuit breakers in the respective circuits.

Maybe that's enough for what you want, but be aware that it's not true 50 amps and won't run everything you could run on true 50 amp service.

Rusty

Tweety's RV calls it a "cheater box" and here is their description and it sure sounds like they believe it makes 50 amps:

The Cheater box plugs into a 20A and 30A outlet on separate circuits to provide a 240V/50A service outlet, enabling coaches with 50A service to have full use of RV appliances. Includes a 30A to 15A adapter. Will not operate on a GFCI circuit.

RustyJC · 10-15-2010, 05:54 PM

It makes 30 amps on one of the 50 amp hot legs and 20 amps on the other ("50 amps" total ampacity) whereas a true 50 amp service makes 50 amps on one and 50 amps on the other (100 amps total ampacity), with the 2 circuits being 180 degrees out of phase such that L1 to L2 measures 240 VAC. The adapter wouldn't produce 240 VAC across L1 to L2 if the hots on both the 30 amp and 20 amp shore power outlets are fed by the same leg (either L1 or L2); rather, the adapter would read 0 VAC across L1 to L2 if that were the case.

Rusty