In the summer it's surprisingly common for power plugs on RVs to be destroyed by excess heat. But it's not the sun's heat that's causing this to happen—it's the result of heavy air conditioner use combined with corrosion on the power plug's metal prongs.
When you're running the air conditioner on a hot day, a lot of electricity is trying to flow from the power outlet to the metal prongs of your power cord. If the metal has corrosion on it, electricity can't flow through that connection as efficiently.
This causes the metal to get hot, which leads to even faster corrosion, which in turns leads to more heat. In a matter of hours the entire thing can get so hot it melts the plastic and can even start a fire. At the very least, you'll lose power and the plug will be destroyed.
There are a few ways to avoid this problem:
1. Keep the prongs shiny
It's simple: No corrosion, no meltdown! The prongs of your power cord should always be shiny yellow brass, not brown, black, or copper colored.
Check the plug each time you plug it in, and if the brass is getting dark you'll know it's time to clean it up. We have a kit that includes tools specifically for this job, and it's easy to do!
2. Avoid extension cords if you can
- Extension cords cause the electrical voltage to go down, which means more heat at the plug connections.
- More points of connection means more places a meltdown can occur.
- A cheap extension cord will take your primary cord down with it!
I speak from experience on this one. As the photo at the top of this blog shows, our plugs were lying on grass for two very humid days with the air conditioning running. The problem started inside the black extension cord's plug because it was a cheap one with thinner metal connectors and probably a bit of corrosion inside. It heated up, and dumped melted plastic on the gray cord that was plugged into it. I explain the details in this 1-minute video:
You can also see that the heat and corrosion turned the metal prong a copper-ish color. I was able to get the prong back to shiny brass so it was usable in a pinch, but not all the melted plastic could be removed. The only solution was to replace the heads of both cords with better-quality parts before they could safely be used again.
If you must use an extension cord, use the heaviest one possible and keep a close eye on it.
3. Limit electrical loads
Late model Airstreams seem to have more electrical appliances every year. Many Airstreams sold in the past few years have dual electric/gas water heaters, electric-only refrigerators, microwave ovens instead of gas ovens, and dual air conditioners.
Many people don't realize that you can't run all that stuff at once. The total power draw can easily exceed what the power cord can handle, even if it doesn't trip the circuit breaker at the campground power pedestal.
For example, the single air conditioner in my Airstream Globetrotter 23FB will draw anywhere from 12 to 18 amps by itself, depending on how hard it's working. The microwave oven needs about 12 amps. The electric water heater is another 12 amps or so. But the trailer's power cord is rated for only 30 amps in total.
To make matters worse, the National Electrical Code calls for using only 80% of the rated capacity if you're going to use it continuously. Well, on a very hot day your air conditioner is likely to run continuously, and that means any load over 24 amps (on a 30 amp plug) or 40 amps (on a 50 amp plug) is asking for trouble.
Don't count on the campground's circuit breaker to save you. If you're running a 30-amp trailer on a 50-amp circuit (using an adapter or "dogbone"), a meltdown can occur long before the breaker ever trips.
An easy way to cut electrical loads is to shut off the water heater during the day or run it on gas mode. Switch the fridge to gas mode too, if it has that option. If you want a quick reheat of last night's leftovers, switch off the air just for a minute while you're using the microwave.
4. Get an EMS
The need to know how many amps you're using is yet another reason to get a good quality Electrical Management System (EMS). The EMS will show the number of amps you're using on the display. That way you can know if you're nearing the limit, and reduce electrical loads before something bad happens.
You should also check the voltage on the EMS readout before you plug in. It's wise to assume that the voltage you see in the morning is the best it will be all day, and probably will go down. If it's marginal, talk to the campground.
An EMS will cut off the power to save your Airstream's air conditioner if the voltage drops too low. In my opinion an EMS is not optional, except for gamblers.
5. Consider a plug upgrade
One thing I really hate about RV cords is that most manufacturers supply only brass connectors. Brass corrodes easily and that's why we all have this problem.
A plating of nickel over the brass is far superior and resists corrosion. That's why marine-grade cords usually have nickel plating. Electrical vehicle chargers use nickel-plated connectors too. When you need a reliable high-power connection that's resistant to corrosion, it's a great choice.
So why aren't nickel-plated RV plugs commonplace? My guess is it's because the RV industry as a whole is way too focused on cutting costs to the bare minimum. (That's another rant I could get on, but I won't do that here.)
I wouldn't go cutting off perfectly good plug ends just to upgrade them to nickel-plated plugs, but since mine needed replacement anyway I went to the small extra expense.
In lieu of marine-grade connectors, a smear of dielectric grease on shiny brass prongs is probably the best and most practical way to keep things happy. Dielectric grease is one of the things included in our Maintenance Essentials Kit, for this very reason. Like the other preventative tips I've listed, it's cheap insurance.