I'm trying to get low voltage wiring from the attic to basement in a house. The problem I'm having is the drill rods I'm using keep snapping the drill heads off after I get three extensions on. Is it that you can only use so many extensions and then they just cannot take the tork? I need to do this and I don’t want to cut hole in the drywall. Do I just want the not possible? This is sensor for HVAC system, has to be away from power and under 200'. I'm using those drill rods that are thin steal and flex with a little self feed bit at the end.