Welcome to my J.A.M. (Just Ask Mike) Session, a weekly column where I answer your basic electrical questions. If you’re a newbie who’s never plugged in a shore power cord (or ask – what’s a shore power cord?), or wonder why your daughter’s hair dryer keeps tripping the circuit breaker, this column is for you. Send your questions to Mike Sokol at mike (at) noshockzone.org with the subject line – JAM. This week I answer a question about splitting a ProPower 30-amp outlet to run two trailers at once.
I’d like to ask you a question about some adapters you may use for the F-150 PowerBoost hybrid… I own one with the 7.2 kW built-in generator and I’m interested in splitting the 240-volt, 30-amp outlet into two separate 120-volt, 30-amp circuits.
It would be really cool to be able to provide power for two 30-amp trailers at the same time. How did you do it with your demo truck? —Gregg S
I’ll admit that this took me a few minutes to figure out, since it wasn’t obvious. And there’s no single adapter cable that will do this. No, it’s a bit of a Frankenstein fix, but still perfectly safe and code legal.
I first hooked the ProPower outlet panel into my 10kW load bank for general testing. This was pretty simple because the ProPower panel has an L-14-30 twist-lock outlet, in addition to a pair of 120-volt, 20-amp duplex receptacles. My load bank will accept either 120- or 240-volt power, so I set it for 240 volts so I could monitor total power available from the PowerBoost truck.
First Connection (one and done)
The truck has an L14-30 twist-lock outlet exactly like you would find on any 5kW to 7kW portable generator. And since I already had an L-14-30P to 14-50R dogbone adapter for my Honda EU7000 generator, I was already halfway there. You can buy one of these on Amazon HERE.
If you wanted to power your 50-amp shore power RV alone, then this is all you need. Just use this dogbone adapter to make a 50-amp outlet just like a campground pedestal. The twist-lock outlet on the truck is wired with split-phase 120/240-volt power with a bonded neutral. So your RV will treat this like a standard campground outlet and split the 240 volts into a pair of hot-legs, each with 120 volts on them.
Second Connection (second verse, same as the first)
But now we need to convert this 14-50R outlet into a pair of TT-30R outlets that can power a pair of RV trailers. Again, this is a stock connector that will split the two hot legs of the 240-volt outlet into 120/120-volt power.
I didn’t have one of these laying around, so I ordered it on Amazon and it was here in two days (Thank you, Amazon Prime). You can get one HERE
If you want to power a pair of 30-amp RVs, then plug the second Y-adapter to the first adapter, and then plug in your RVs. The PowerBoost truck even has a cool on-screen app that lets you monitor outlet power on each of the legs.
Since these are bonded neutral outlets with GFCI protection, it may be possible to trip the GFCI with an RV that has too much hot-to-chassis leakage (over 5mA). Apparently Ford is aware of this and is supposed to come up with a software patch soon. But I’m not in that loop, so I’ll have to wait for an official announcement from Ford. But it worked perfectly on the three different RVs I experimented with.
That’s a wrap (for now)
I’ve asked Ford to provide me with an F-150 Lightning loaner as soon as one is available, so I’ll let you all know when it arrives, probably early 2022 according to my media contact.
OK, everyone. Remember that electricity is a useful and powerful force, so we all need to pay attention to safety precautions while using it.
Let’s play safe out there….
Mike Sokol is an electrical and professional sound expert with 50+ 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.
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