Is there something that makes GFCI outlets trip easier in cold weather? I'm having a shit time trying to get my block heater to stay going more than 5 minutes, this is on one breaker. My christmas lights are on another breaker coming off the back of the house, they're drawing less than 300W and they're tripping every few days as well. Not sure what's going on. Have the clear, hinged weatherproof boxes over them as well. Or did the guy before me buy junk shit chinese GFCI's?