Monday, December 5, 2022


Are all RV power adapters created equal?


By Russ and Tiña De Maris

A regular reader sent us this interesting question:

“I bought a popup camper a few years back that had the various plug adapters included. Last year I sold the popup and purchased a travel trailer, but kept those electrical adapters. Here is my question: Can electrical adapters be as safe as a dog bone adapter? In the picture you can see that 30-amp adapter plug appears to have been heated to a point of a meltdown.”

Melt-downs of electrical adapters (and even electrical plugs on the ends of power cords), of course, are traced back to heat. Why did the heat develop in the first place? When too much electrical current is asked to go through a connector, there’s a huge heat buildup. The connector picture you show is a 15 amp on the “delivery” side and I would guess probably a 30 amp on the receiving side. Someone probably tried to pull more than 15 amps through this fitting, and although it wasn’t enough to trip a breaker, it did overheat the adapter. It’s also possible that only 15 amps was called for, but the material of the adapter just wasn’t up to the task.

As to a dog bone-style adapter having better resistance to heat (and therefore avoiding meltdown), well, there’s a subject that’s open to argument. This link goes to an outfit that swears its adapters (non-dog bone) are safer, “provide superior durability and heat resistance over ‘dog bone’ type adapters.” And on the other hand, dog bone manufacturers will tell you their product is more heat resistant. Wow, leaves us consumers with a guessing game. Do we believe any of the hype? Here’s our experience:

We have, and use, both styles of connectors, and haven’t had any meltdown problems with either. However, there’s another factor to consider. Keeping the contacts on your plugs clean and shiny is a critical factor. The copper in the prongs is subject to oxidation; the greater the level of oxidation, the more resistance to the flow of electrical current. The greater the resistance, the greater the buildup of heat. So, take a look at your rig’s electrical plug and take after it with fine grade sandpaper if it’s not shiny — that will help.

And like the “chain is only as strong as its weakest link,” you cannot call for more power than the lowest value in the system. If you’re hooking up your travel trailer (and I’m guessing it’s a 30-amp service) to a 15-amp circuit, you cannot safely draw more than 15 amps. Translated: Not likely you’ll be able to run an air conditioner, and you’ll need to be careful about how many large-current items you run at the same time. In our case, we don’t fire up the microwave oven at the same time the toaster is going when we’re tapped into a 15-amp circuit.


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5 years ago

Dog bone connectors that hang from an electrical service are a real danger to male dogs who decide to raise a leg while passing by. It either lights their “fuse” or can kill them. Either 30 or 50 amps!

5 years ago

The sort of simple meter im talking about:

I have a similar 5-way meter on my generator that also displays wattage, runtime, and accrued watt hours.

5 years ago

The addition of a $6 AC volt/ammeter is a powerful tool (NPI) towards knowing what each appliance actually draws, the total instantaneous draw, and when voltage is sagging (by sharing campground lines or your own overloading). At this point, i wouldn’t run an RV without one, as it has probably saved me lots of repair bills.

I’d also recommend staying a margin of safety from the stated maximum draw, having melted cords at 90% draw… Sustaining 27A on a 30A service noticably heats up the cord and outlet, and I’m not a fan of pushing limits.

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