My '99 Silverado w/ 5.3 liter gas has an engine block heater. It was supposed to be around 0 (that is cold around here) so I decided to use the block heater. Didn't notice it when I had used this in the past, but whenever I plug it in to the outlet on my outside electric pole it kicks the GFI. I know (or at least think) the GFI is good because I used it at Christmas for lights. I moved the cord over to the outlet in the shed that isn't GFI and it seems to be working and it hasn't kicked the breaker. Is this common for block heaters to kick a GFI outlet?