RV Electricity – Can I plug my 50-amp RV into a 240-volt generator?

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By Mike Sokol

Dear Mike,
We just bought a travel trailer with 50-amp service. Can I plug my trailer into my generator directly? The generator is 50 amps at 240 volts. The RV is a brand-new Rockwood 2912BS. Thanks. —Bruce Johnson

Dear Bruce,
Are you sure your generator is actually rated for 50 amps at 240 volts? That would be a 12 kW generator which is not very portable. A 12kW genney would need Cam-Lok connectors or a CS-50 (California) outlet to work. Let me know the make and model of your generator and I’ll look it up.

Most likely your generator could be something like a 7,000-watt Honda EU7000 which has a 4-wire/twist-lock/30-amp outlet with split-phase 120/240 volts. That will work perfectly with the proper dog-bone adapter. You’ll be limited to around 30 amps per leg, but since you have two legs that would be 60 amps total current for your RV.

Dear Mike,
No worries, this is a Firman generator with 30- and 50-amp outlets. Just wanted to make sure my travel trailer can handle 240 volts without any problems. Thanks again. —Bruce J.

Dear Bruce,
Remember, your RV needs split-phase 120/240 volts with a 2 hot poles, 1 neutral and 1 ground. That takes 4 wires in the generator to do this. And this size generator may also have a 3-phase/1-phase selector switch and possibly 208/240/480-volt settings as well.

I almost lost an entire music stage of expensive gear when one of my technicians tried to hook up to a rental Whisper Watt generator without my help. I ran over before he started it up, and sure enough it was set to 3-phase output and 277/480 volts. It would have been a disaster had he started it up and threw the master circuit breaker to power the stage. 

Also, make sure you’re connecting the RV’s shore power line to the neutral of the generator as well as the two hot poles. And you might need to add my G-N bonding plug to any 20-amp outlet on the generator to bond the neutral and ground in the generator together, especially if you have any type of Intelligent/EMS surge protector that tests for open ground. But on a generator of this size, the neutral and ground are typically bonded together with a bus bar. 

Let’s play safe out there….

 

Mike Sokol is an electrical and professional sound expert with 40+ years in the industry. His excellent book RV Electrical Safety is available at Amazon.com. For more info on Mike’s qualifications as an electrical expert, click here.

##RVT896

 


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Dave Telenko
Dave Telenko

Hi Mike is there an EMS for your “almost disaster”? Hmm seems like a timely question, with your Sunday portable generators discussion coming up tomorrow 5/12/19!
See ya
Dave Telenko

Mike Schwab
Mike Schwab