Melted Cord!?!

[aluminitus]

Today the temperature got up to 110 here in Tucson and I got a call from my husband telling me to come home from work and bring some supplies because the female end of the power cord had melted and fused with the male inlet on the Airstream.







We have one air conditioner (30 amp) which was running, and are plugged into shore power with a high/low voltage surge protector between us and the pedestal. The only other power usage in the trailer was the refrigerator and a plugged in laptop. The air conditioner had been running for hours, and nobody else in the park reported any kind of a power drop or surge. Our surge protector read "low voltage" and there was no power coming through the cord, so the surge protector must have cut off the juice.

We replaced the melted parts and everything seems to be working now, but we don't know what caused this to happen. My biggest fear is that this will happen while we are out and the AC will turn off and our dogs will overheat quickly in 110-115 temperatures. Any ideas what could have caused this to happen?

[Al and Missy]

There are several possibilities:
1. Loose connections in the plug or socket at the trailer. This could increase the resistance through the connector, generate heat, cause dropping voltage, resulting in the AC to draw more current, generating more heat, etc. Ultimately it could get hot enough to melt the plastic.

2. Corroded pins or sockets at the trailer - same results as above.

3. Low voltage in the park - causes the AC to draw more current. When I had this problem, the breaker in the trailer tripped repeatedly, but the connector didn't overheat.

I'm guessing if you replaced the socket and plug at the trailer you fixed the problem. To be sure, measure the voltage in the trailer. It should be 110 volts or higher.

Al

[aluminitus]

I think our neighbor drives over our cord with his motorized chair...would it loose connection have to be at the trailer or at the power pedestal for the trailer side to melt? The pedestal side was fine.

[Al and Missy]

Originally Posted by aluminitus

I think our neighbor drives over our cord with his motorized chair...would it loose connection have to be at the trailer or at the power pedestal for the trailer side to melt? The pedestal side was fine.

In my opinion, only the trailer side. That's where the heat was generated, that's where the resistance was high.

Al

[Protagonist]

Originally Posted by aluminitus

I think our neighbor drives over our cord with his motorized chair...would it loose connection have to be at the trailer or at the power pedestal for the trailer side to melt? The pedestal side was fine.

Those shore power cords are pretty durable in that regard. Besides, if the cord was damaged by a motorized chair, it would melt where the damage occurred.

In order for his chair to damage the cord at either end, he'd have to snag the cord and drag it. If this happened, damage is more likely at the trailer end because the plug is locked into the socket and the wires could be pulled loose from the connectors inside the plug; at the pedestal end, it's more likely that the plug would just be pulled from the socket, possibly with bent prongs if it wasn't pulled straight out.

If your cord is strung across an area where someone in a motorized chair has to travel, it's best to protect the cord— and the person in the chair— by covering the cord. Something like this…

These covers are usually made of soft rubber or plastic, and can be slit along the bottom to insert the cord. Prices vary by style and manufacturer, but about $6 per foot of length is typical.

[J. Morgan]

Where the heat was was your problem. For one reason or another you had a poor connection, the new hardware should take care of the problem.




Superat stultitia.

[aluminitus]

Thanks for all of your help!

[AtomicNo13]

Its a good idea to frequently clean all the contact surfaces with either an electrical deox spray or use.something lime.bar keepers friend to make.the.contacts.shiny again.
although its a stick mess, an electrical grease is a great idea on all the same surfaces. Anytime you have an oxide form on your contacts, resistance can go sky high.and.cause heat.... as you know!