I need heat in my garage this winter and would like to use my dryer outlet to plug into my garage heater. there is 6' of 12-2 cord attached to the unit which isn't long enough to reach the 15' I need. my plan is to attach a replacement dryer cord 10-2 to a 10' 12-2 I purchased at hd. I drilled a 1" hole through the wall and want to mount the unit on the wall. My question is can this be done safely