So...... Earlier this afternoon I had a breaker trip that prevented the laundry room light from working. I reset the breaker and all was good. So I thought!
A couple of hrs later, as we were leaving, my daughter informed me that the laundry room lights were again, not working.

As we were running late I elected to investigate when we got back home. I was removing ice from the truck when my daughter came out, and I told her to unplug the truck since she was closer.

When we got back home I went to plug the truck in and I noticed both the truck end , and the female end of both plugs were charred and somewhat deformed, indicative of them both being hot. The plug in the garage outlet was fine!

I immediately put 2 and 2 together and realized this was the reason for the breaker tripping.

The cord I use is dedicated to my truck, and seldom gets used for anything else. I been using it for 3 yrs., and it is in good shape with no cuts or bad areas. Any electricians out there who can shed some light on what might have caused this? Could it have burnt my heater up?

 

What size cord you using? and how long is it?

 

Hey Richard, It's 12ga and its only about 10 ft long . Its worked fine for at least 3 yrs now.

 

That should be plenty heavy enough - Make sure the plug prongs (both male & female) are clean & making a good connection. Loose connections will cause overamperage and charring or loose wire on the plug end ?

 

That cord is plenty big enough do like Bill said and check the ends on both cords. Also check the condition of the block heater cord it goes all the way back to the oil filter.

 

Mine does that too but I believe the wire that connects to the male plug is just getting old and oxidizing. I actually had to cut my male plug off and cut the wire back some and get a new plug from HomeDepot. Later when I get a new bumper I'm putting the plug in the bumper with a water tight lid on it to keep the wires and plug from getting exposed to water and road grime and oxidizing.
When the wire starts to oxidize it creates more resistance which equals more heat which causes more deterioration and then starts a ruthless cycle of heat, oxidation and resistance.
I would do what these guys said and make sure there aren't any hard spots in your wire for your block heater. Check near where you plug it in. If there are hard spots then cut the wire and replace your plug.
I would also check the resistance of your block heater but I don't know what the resistance is supposed to be. I know the shorter the wire the less the resistance but they all should have a optimal range.

 

I think this nails it. Most of the block heater cords at work show some signs of heat. I also had to put a plug on mine last week. These new liquid deicers they use now days are hard on wiring. Most of our trailers had problems the first winter it got used around here.

16 ga wire is around .005 ohms per foot, so if you see more .05 ohms on a leg of the cord I would look for problems. Myself, I would check for bare spots and try a new plug. Then go from there if you have issue's.

 

Agreed. New plug on the heater cord with a protective cover, and replace the female end on the extension cord (or replace the extension cord). Have a look at the opposite end of the heater cord (next to the oil filter) just to make sure everything is "cool" there.

All that moisture and oxidation on the plug makes for a poor connection after a while, which generates sparks and heat.

 

Thanks for all the info guys...... Plugged it in last night with a different cord and will be going out in a few to see if the heater is working.

 

I was afraid that my plug end of the truck was showing signs of wear so I proactively did this mod: Marinco Plug mod

 

You can get the Marinco inlet plugs for like 18 bucks on amazon right now. I think i am going to try to do this one soon.