Snow Melt Plaque (NEC Requirement) (SMP)

Once you've decided what type of heating system (manual vs. automatic), you'll need to choose a control, which may or may not utilize a sensor. You may need a relay panel(s) depending on the size of the system, and a snow melt plaque which is required by the National Electric Code. Junction box(es) may be optional depending on the distance of heating cable from the indoor power location.

Any outdoor rated plastic, watertight junction box will be acceptable.

A 2 pole single-phase 240V circuit works by continuously monitoring the current flowing through both hot wires of the circuit. If it detects even a slight imbalance between the current on each hot wire (indicating a ground fault), it will quickly trip, cutting off power to the circuit. Essentially, it compares each leg of the 240V circuit and trips if they are not precisely equal.