I had a problem last winter with ice dams on one portion of my roof. So I removed drywall. Installed soffit and roof vents in my attic and properly insulated the attic. I think I took care of the ice dam problem but just in case I installed easy heat cable on that small section of my roof. My question is in what temperature should that cable melt the ice and snow? We had 4 inches of snow last night and I turned on the cable and it doesn't feel warm to the touch and is not melting any snow. It is only 7 degrees out right now. I know that the cable doesn't get real warm just enough to help clear a path for ice dams but the instruction manual said the cable should feel warm to the touch. Any help or knowledge would be greatly appreciated.