2012 Hyundai Veracruz Melted Block Heater
This happened in Dec. 2013, I plugged the extension cord to block heater plug and started clearing snow from sidewalk, after five minutes while clearing snow close to vehicle, I noticed red glow under the chassis. Immediately unplugged extension cord from wall, opened the hood and could clearly see flames deep down where block heater attaches. I used fire extinguisher to put fire out, called my Hyundai dealer next day, they told me to bring it in, also told me it is safe to drive it.
At the dealership they found it totally melted and also damaged the motor mount. Block heater was replaced after a week but still waiting for the engine mount as it has to be imported from Korea.
They also tested my extension cord (14 ft, 14 gauge contractor grade), no damage to it and no issues found. The tech was unable to answer why and how this happened. I am now reluctant to use block heater until I find some answers. I have attached couple of pics and would appreciate if anyone can shed some light.