Power Cord/Extension Cord Melted Together

Melting electrical components sounds pretty concerning to me. I don't believe my electrical chords have ever even gotten warm to the touch, let alone so hot as to melt plastic or rubber. Yikes!

Hi Naio,

Folks don't seem to be aware they can use more than the capacity of a 15 amp circuit for some time without blowing the breaker on the shore power supply. Of course, as voltage drops anything with a motor (i.e. the air conditioner) draws more current. The same thing happens as the ambient temperature goes up.

For example, my air conditioner, on a 15 amp shore power connection ended up drawing over 18.5 amps, due to voltage drop and high ambient heat of 41 c (105 f). Because I do monitor that sort of information, I disconnected and moved over to using the generator. On the generator, it drew only 13.3 amps.

I appreciate your patience with me, Don :). I am still confused. Why would the heat be building up specifically in the adapter? Because it hold two plug connections (innie and outie) in close proximity?

(FWIW, we don't generally use more than a few amps. No AC or heater. And I was about to buy an adapter, so I want to be sure I am getting the right one :).

Hi Naio,

The good:

They are small and don't take a lot of storage space

The bad:

Because there are two sets of contacts in close proximity there is more chance of heating. Because 15 amp outlets are often abused they do not connect well, so even with low amperage (your converter may draw 6 amps if it is small--and twice that if it is large) heating may occur.

The ugly:

They don't always fit the shore power cord box well--and if the female shore box outlet is worn (and they often are), the extra weight may cause the connector to fall out of the plug--leaving you with no power in the middle of the night.

Because they are small, they are easily lost. (or they hide from you).

Do yourself a favor and spend the extra dollars on the Dog Bone. Get one with right angle plugs if you can find it. They "hang" better on the shore power outlet.

I carry a 15 to 30; a 30 to 15; a 50 to 30, and a "break out box" that converts a 50 amp shore power to a 30 and two 20 amp females that have their own circuit breakers.

X2 what PIANOTUNA says

I suspect the adapter and extension cord have been connected together too often while the power is still on.

Many folks plug their cords in while live, instead of turning off the power at the source (CG pedestal, or breaker at home) or inside the camper. Every time you plug in live, there is a momentary inrush current caused by the converter. This is the zap you will hear, and in the dark, a flash as well. This causes pitting on the blades of a plug and inside a receptacle or inside the connector on the end of a cord. The more you do this, the worse the pitting gets. The pitting also attracts dirt. The result is that resistance rises over time to the point where it gets hot. It can melt things or even cause a fire. A meltdown usually happens at the pedestal end of the cord, but I saw a photo once of a burned out power inlet on the side of a TT. The owner was always plugging in at the pedestal first, then attaching his detachable shore power cord with the power on. He was lucky that it only damaged his inlet fitting.

When we first got a TT, I used to plug it in at home to keep the battery charged and fridge running on 120V. I ended up having two extension cords go up in smoke. I eventually installed a 30A RV outlet in our carport along with a disconnect switch below it.

You should periodically check the blades on the end of the shore power cord and clean with fine emery cloth or steel wool. There's no way I know of to check inside a recept. or connector.

The reason that the compact "puck" style adapters don't work as well is because with the short length of the adapter, you have prongs/blades inside the connector/receptacle end and blades at the plug end in close proximity to each other. If they are both pitted and dirty, there is more heat concentrated in a smaller area. With a dogbone adapter, the plug and connector are separated by 18" and there will be little heat transferred from one end to the other.

If you want to plug into an extension cord at home, always turn the power off first at a breaker. Secondly, use a heavy duty extension cord. A #12 gauge cord will not only have lower voltage drop, it should have a more heavy duty connector on it.

I've always eventually had trouble with the connector end of even heavy duty contractor grade extension cords. They always seem to lose tension of the contacts inside the connector/outlet and eventually make a poor connection. If you do get a heavy duty cord, you might consider getting a high quality plug and connector and replacing what the cord came with. You could use something like this Leviton connector (and matching plug) which is industrial grade with a lifetime warranty.

I have a 25' 15A extension cord I made up that I store in our TT and I used a Marinco connector and plug on the cord.

When home, I plug the TT into a 20 Amp circuit in my garage, utilizing a heavy duty extension cord that matches the TT power cord, as well as an adapter to a standard receptacle. I have never experienced problems with heating, but I can confirm that it is not a good idea to plug in to live power. The adapter plugs into a power outlet strip that I turn off every time I plug in or unplug. At CG sites, I always make sure the power supply breaker is turned off before plugging in the TT cord.

Thanks all, lots of good info. For what it's worth, the connection was laying in the grass for 4 days & we had a lot of rain on day 3. On day 4 when DW was making coffee the GFI tripped. I always turn off campground breakers before plugging/unplugging & I seldom have to use the extension cord. I plan on replacing the cord ends & in future when I do have to use the extension cord I'll be checking the connection regularly.

Arn wrote:
Now to figure out why they melted together.

The usual cause is drawing too much current for them to safely pass. That, and corroded socket or pins. Happens over time.

It's always a good idea to check connections for heat during time you're drawing a lot of power. If they're hot, then cut back.

Thanks, pianotuna and Roy!

And myredracer, that was great info :).