50 amp to 30 amp

[kycamping]

Going camping this weekend and have a question? Our camper is 50 amp but the campground only has a 30 amp service. Here is the question I only have a extra 30 amp cord not a 50 amp and the hook up is longer than me 50 amp cord. Is it ok to use the adapter and plug the 50 amp into the 30 amp and then to the box? Also was wondering how to plug up my surge protector with this set up. Thanks

[fredetteb]

You shouldn't have any trouble using the setup you describe. 30A cable from the campground hookup . . adapter . . surge . . 50A to camper. We have done the same thing several times with our 50A camper.

Do keep in mind that you may not be able to use all the electrical items you want at the same time. Things like the water heater, TV, Refrig, and Converter are using some portion of you total current. Adding A/C, Micro, Hair Dryer.. will pull more amps.

[chuckster57]

There is an adapter that will let you plug your 50A into it and it in turn plugs into the 30A and 15A for a total of 45A, getting you close.

[grayghost03]

There is an adapter that will let you plug your 50A into it and it in turn plugs into the 30A and 15A for a total of 45A, getting you close.

As chuckster said, the 15amps will help, but remember you will not be able to use everything, like you can on "50 amp" because 50 amp is actually 100 amp, two 50 amp feeds, coming into 2, 50 amp mains, giving a total of 100 amps of usage power, that's why you can run 2 ac's and microwave, and hotwater heater, along with other things with out tripping the breakers, using the 30 amp and 15 amp supplemental, you will be tripping breakers. But it is better then just the 30 amp.

[bobbecky]

Remember to switch the fridge and water heater to gas only when using a 30 amp connection. This will take some of the electric load off of the system.

[christopherglenn]

The 30 + 15's rarely work anymore. All the 15 amp plugs *should* have gfci's on them. The 30+15's only work on the older non gfci plugs.

[Tom]

I'm having a really hard time grasping the concept that a 50 amp trailer can really draw 100 amps without a problem.

[chuckster57]

because 50 amp is actually 100 amp, two 50 amp feeds.

Not really. There is two "legs" in a 50A RV cord, Leg 1 will be 30A and Leg 2 will be 20A for a TOTAL of 50A

[Javi]

I'm having a really hard time grasping the concept that a 50 amp trailer can really draw 100 amps without a problem.

It can... and it can't.. if you use a meter you will find that you have a split 240 service... one leg is 120volt 50 amp and the other leg is 120 volts 50 amps.. for a total of 100 amps..

Now.. you can't use all 100 amps on one circuit or run of wire.. each run gets 50 amps.. RV manufacturers wire the trailers and MH's so that the 240 volts is split into two 120 volt runs..

Both legs carry 120 volts and 50 amps..

So 50 amp service is really 100 amp it just isn't all available at any one plug or run.

[Festus2]

because 50 amp is actually 100 amp, two 50 amp feeds, coming into 2, 50 amp mains, giving a total of 100 amps of usage power,.

If the RV is wired for 50A and you are plugged into a 50A service at the pedestal , then that is what you get - since only 50A is actually usable. I don't think you get 100A of usage power.

[Javi]

If the RV is wired for 50A and you are plugged into a 50A service at the pedestal , then that is what you get ---- 50A not 100A - is it not? I too do not follow your explanation that "50A is actually 100A".

How does a 50A wired RV's electrical system cope with 100A of usage power?

:confused: Very puzzled by your statements.

See my post

[Festus2]

See my post

Javi- Sorry, I revised my post and you quoted my original one. But you did clear up my confusion....... not an easy task BTW.

[chuckster57]

I will freely admit to not knowing a lot about electricity other than it can HURT you if treated wrong. So maybe someone can explain to me in "electricity for dummies" language.

In some RV's I work on, there is a display panel and it has the ability to show you how many amps your drawing on shore power, and how much is being used at any time. When I am plugged into a 50A service, I see L1 @30A and L2 @20A.

My Dad was an electrical engineer and tried all the time to explain how this stuff "worked", but I didn't listen.

[Javi]

I will freely admit to not knowing a lot about electricity other than it can HURT you if treated wrong. So maybe someone can explain to me in "electricity for dummies" language.

In some RV's I work on, there is a display panel and it has the ability to show you how many amps your drawing on shore power, and how much is being used at any time. When I am plugged into a 50A service, I see L1 @30A and L2 @20A.

My Dad was an electrical engineer and tried all the time to explain how this stuff "worked", but I didn't listen.

That's not uncommon.. what you are seeing is draw not available amps.. If you turn on another appliance or plug in a hairdryer you will see that amp draw increase on one of the legs. Each Leg is capable of 50 amps.

[chuckster57]

I'll try that. Thanks.

[HappyCamperMN]

For anyone not believing / following Javi's (very good IMHO) explanation, please see this link -> http://www.myrv.us/electric/pg/50amp_service.htm

A couple of excerpts...

From this common service we can draw 120 or 240 volts. Each leg is 50 amps @ 120 volts. 50-amp X 120-volt = 6000 watts. But since there are 2 HOT 120-volt legs at 6000 + 6000 = 12,000 watts to use in the RV or 50-amp X 240-volt = 12,000 watts when used as a 240-volt service.

The 50-amp 3-pole 4-wire service is superior to the 30-amp service because of the total amperage available.

30-amp 120-volt service = 3,600 watts
50-amp 120/240-volt service = 12,000 watts

[Tom]

I've got it now, the panel in a 50 amp trailer is just like the panel in my house except that my house has 100 amps per leg instead of 50. If the legs were balanced in the trailer like they are in the house then you could actually get 100 amps from the 50 amp service. The problem with that is that if you had to use a 30 amp supply then you would lose out on everything powered from the B leg. That wouldn't be good if something you needed was on the B leg.

I've never seen the electrical panel on a 50 amp trailer but I assume the only thing on the B leg is the second AC. Is this true?

[bobbecky]

A 50 amp trailer plugged into a 30 amp supply, using a 50-30 amp dog bone adapter, is connecting the single 30 amp/120 volt leg to both the 50 amp legs going into the trailer panel. You will only have 30 amps available for everything in the trailer, instead of the total of 100 amps from the two 50 amp legs when connected to a 50 amp pedestal. If you are connected in the summer months when an A/C is needed, it is wise to turn the water heater and the fridge to propane only, and when running only one of the A/C's at a time (if you have two units), you may need to turn the A/C off if the use of the microwave is needed.

[Tom]

Another dumb question: since the trailer manufacturers don't use more than 50 amps in their trailers anyway, why run 2 50 amp legs into the trailer when 1 would seemingly be enough? What does having a second 50 amp leg accomplish?

Obviously I'm not an electrical engineer.:( I understand the workings of 30 amp service fine but am confused about 50 amp service.

[Javi]

Another dumb question: since the trailer manufacturers don't use more than 50 amps in their trailers anyway, why run 2 50 amp legs into the trailer when 1 would seemingly be enough? What does having a second 50 amp leg accomplish?

Obviously I'm not an electrical engineer.:( I understand the workings of 30 amp service fine but am confused about 50 amp service.

If you consider all of the appliances, air conditioners, hairdryers, microwaves, converter, chargers and other stuff we run or plug in to our trailers you'll find that the potential is there for more than 50 amp draw at any one time.

Tom, understand this is 120v/240v 100a service... all that's done is to split it at the service panel "IN" the trailer into two 120v-50a circuits but make no mistake; you have the potential to use all 100 amps of available draw. In fact some top end RV's like the Provost do in fact use the circuit as 240v-100a service, and just like your stick house split that at the service panel to provide 120v/30a, 20a and 15a.

[christopherglenn]

It is not that hard to exceed 50 amps in an rv with 2 ac's. I can run (barely) both ac's on a 30 amp. With the charger off, and the fridge on gas. The local lake only has 30 amp at the larger spots, go figure. The fridge is a maybe with both ac's, the charger popped the braker at the panel. Assuming the microwave pulls close to 8 amps, battery charger, and a simple hair fryer (drier) at about 13 amps, you are over 50 amps. Some of the toy haulers have a 3rd AC in the garage.

As for the confusion on the naming of 50 amp services, they are 50 amp 240 volt - hence the name, we are splitting them into 2 50 amp 120 volt services internal to the rv. I have yet to see any 240 devices (other then transformers and surge supressors) in an rv from the factory - none of them would work on 30 amp or less.

The 30 amp adapters put 120 volts to both sides of the internal braker panel, so everything works, and unlike the 50 amp - which is up to 50 amps in both sides, there is a total of 30 amps between the sides. You can split it 15-15, 5-25, or put all 30 on the same side, it doesn't matter.

[Tom]

Very interesting & informative- for sure my next trailer will have 50 amp service AND 2 air conditioners.

It would sure be nice to be able to run numerous high draw electrical appliances without running out of juice. It gets old having to flip the water heater breaker (wish it had a switch assessable from the coach interior) whenever we want to use the microwave and the ac is running (which it always is during the summer).

Back in the old days, Fleetwood 30 amp products had a switch by the microwave that said microwave/water heater. With this switch you had to turn off the water heater to run the microwave. This was a great idea which unfortunately died out.