Can you plug your trailer's 30 amp to 50?

[HEYBOSS]

Went to a local camp ground to look at some site reservations and they tell me I shouldn't plug my trailer's 30amp service into 50amp service. I've never heard of it and my camper's manual doesn't mention anything! Any help is appreciated, Fred.

 

[Fireman Dave]

I think the other way around may be something to worry about, but I don't think 30 into 50 should be a problem. I'm no expert, though. All I know is how to plug in - not much beyond that!



I'll be interested to see what someone who knows about this says. I just got a big trailer this year - 30 amp also, so I'm learning too.

 

[B.G. Smith]

30 to 50

Fred, there is an adapter that plugs into the 50 amp outlet and has a 30 amp receptacle on the other end. They are normally about $19. 00 at RV places. It only picks up one side of the 50 amp circuit. You can make one but won't save any money unless you can get the material by scrounging. The 50 amp outlet is two 110 volt lines so you only want to use one side. You need to get one of the adapters, as you will sometimes run into a park that only has 50 amp outlets. bg

 

[HEYBOSS]

Re: 30 to 50

Originally posted by B. G. Smith

Fred, there is an adapter that plugs into the 50 amp outlet and has a 30 amp receptacle on the other end. They are normally about $19. 00 at RV places. It only picks up one side of the 50 amp circuit. You can make one but won't save any money unless you can get the material by scrounging. The 50 amp outlet is two 110 volt lines so you only want to use one side. bg

Two 110 volt lines? That would be 220 volts, never seen at camp ground. Correct me if I'm wrong. I think they all are 110, just that you can get the extra amperage out of 110 if you run more appliances, two roof ac's etc.

I tend to agree with Fireman, it would be a problem if it was the other way around, 50 into 30. The owners manual tells me not to plug it into something less then 30 amps. Now could it be that the converter being rated for 30 amps could be the reason? But then again I would think that if we overload a circuit in the trailer, one of circuits on the trailer's board would trip! Then I couldn't see how it would be a problem.

 

[B.G. Smith]

50 to 30

Yes,it is two different phases of 110 but you only pick up one for the 30 amp circuit. In a unit with the 50 amp power supply, yes, you could have 220. bg

 

[HEYBOSS]

Re: 50 to 30

Originally posted by B. G. Smith

Yes,it is two different phases of 110 but you only pick up one for the 30 amp circuit. In a unit with the 50 amp power supply, yes, you could have 220. bg

Ok. Now I'm starting to understand it. Let me throw another one at you. If it is a 50 amp circuit with the two legs, then with the adapter using one leg, I will have 25 amp service? Now I'm under the 30 amp rating that is required by my trailer! Thanks for the replies, this is very educating, not only to me, but for everyone that reads it, Fred.

 

[klenger]

Connecting a lighter load on a circuit will not cause any problems. Think about it this way ... the outlets in your house are on either 15 or 20 amp circuit breakers. If you plug in a clock or whatever that draws a fraction of the 15 amps it doesn't damage anything. It just uses less of the available power. On the other hand, you should not connect a load that uses more current that the circuit can handle, or the breaker will trip. You wouldn't want to connect your 30 amp trailer to a residental 15 amp circuit and run the AC and microwave.



If you are going to make an adapter to convert 50 amp service to 30 amp service, make sure you connect between one of the 115 vac hot wires and common. If you connect across the two 115 vac hot wires (230 vac), you will burn up everthing in the camper.

 

[HEYBOSS]

So it all makes sense as to why the camp ground does not recommend plugging into 50 amp service, they just couldn't answer me why, and I like to know all the Y's. I was not aware that 50 amp services had 220 volts, live and learn as they say. So BG is right, I can use an adapter and plug into it, I'll probably just be under the rated 30 that is required, but get by for short term use only.

 

[David Oxland]

I've not seen a trailer that takes 220V but it's best to check it out with an electrician; any on board?

The caution with making a 50 amp current available to a system dedsigned for carrying 30 AMP is very much the same as changing a home fuse from 15 to 20 AMPs. You are now proposing to allow 50 Amps of current flow in a conductor and busbar designed for 30. Could be a recipe for fire and destruction. Be Careful here.

 

[JSchooley]

50 Amp service is designed for trailers with extra loads such as washer dryer and 2nd air conditioner.



All residential AC is split 220 VAC, 220 VAC with the center tapped to ground/common. Either side is 115 VAC with the full span being 220 VAC.



On 50 Amp service, 220 VAC should be available for appliances such as clothes dryers. Most service is like house current, split between the two 115 VAC halves. The most use is feeding separate air conditioners, which both use 115 VAC, but from the two sides of the circuit.



There is nothing wrong with pluging into the higher rating as long as you have the appropriate adapted.

 

[Paul Somers]

BG is right. If you take a volt ohm meter and measure across the receptical you will read 220V. Read one of these legs to netural and you will read 110V. The 50A to 30A adapter only uses one leg of the 220. And you will have 110V at 50 amp not 25 amp. A two pole 220 volt 50 amp breaker is 50 amp per leg not 25 amp.

 

[RustyJC]

50 amp RV service uses 4 each #6 leads - 2 hots, each capable of 120VAC and 50 amps, 1 neutral and 1 ground. It is essential that the 2 hot legs be wired 180* out of phase to avoid excessive neutral leg currents. If these hot legs are 180* out of phase, a voltmeter will show 240VAC across the 2 hot legs and 120VAC from either hot leg to neutral. With the hot legs 180* out of phase, the neutral leg current is effectively the difference between the hot leg currents; if the hot legs are in phase, the neutral leg current is effectively the sum of the hot leg currents - if each hot leg were carrying 45 amps, the neutral current would be 0 amps if the hot legs were wired correctly, but 90 amps if the hot legs were miswired, thus overloading the #6 neutral lead.



Therefore, an RV with 50 amp service has a theoretical ampacity of 100 amps (2 each hot legs times 50 amps per leg) versus an ampacity of 30 amps for an RV with 30 amp service which only utilizes 1 hot leg capable of 120VAC and 30 amps, 1 neutral and 1 ground.



If a 30 amp RV is plugged into 50 amp service, it picks up one of the 50 amp hot legs that is protected in the shore power box by a 50 amp breaker. The only protection against overcurrent for the 30 amp RV, therefore, is the 30 amp main breaker in the RV's power distribution panel.



Rusty

 

[Okie-Go]

At our campout in Kerrville I blew the breaker on the post in the trailer park twice in the 30 amp side in about three hours. I found my adaptor and plugged into the 50 amp and had no more problems the rest of the weekend.

 

[Vic]

I carry a 50 to 30 amp converter obtained at Camping World and have used it occasionaly without any problems. Actually I prefer to plug into 50 amp service since it tends to be more lightly loaded in RV parks. That is, the voltage is less likely to drag down during peak power utilization periods in the park.



Up in Canada an electrician got excited over my using my adaptor saying it was unsafe. His reason was that in the event of a short in the trailer not protected by the trailer's circuit breaker that the park connection was mis-sized and something could burn up between the park connection and the trailer circuit breaker. I think that's a very remote possibility, so I don't worry about it.



By the way, I carry a voltmeter pugged into one of the trailer's 115 volt outlets just to monitor park voltage levels. camping World also sells a handy plug-in meter. Have found some parks with really low voltage levels, like 105 volts. Low levels can lead to the stall of the AC compressor and probably aren't too good for the microwave either. Of course, when voltages are low, we'll reserve power for the critical stuff like AC and leave the refrig and water heater on propane.



Enjoy.