Thermostat and common bell wire have this rating. MOUNTING TO OUTLET BOX: A standard electrical box (not included) may be used with the sensor plate as its cover. This provides room inside box for wire nut connection between sensor wires and wiring run to the thermostat. USING SENSOR PLATE: Attaching the plate directly to the outside wall simplifies mounting and requires less space, but the wire nut transitions to the thermostat wiring now need to be made within the wall. This may be difficult i