Basic Installation of the Roof Heating Cable
Choose a starting point
The starting point for your system will be based on the location of your outdoor electrical outlet (if you are using the NAMSR-Kits) or the junction box routing to the controller (NAMSR cable).
Plan the pattern on your roof
There are multiple methods for applying the cable to the roof and gutters. We recommend you plan a written route for the cable to ensure the most efficient path and installation method for the heating cable.
Note that the heating cable is specifically intended for problem areas and does not need to be installed on all areas of the roof. In some instances, on high-pitched roofs (over 40-degree slope) and on roofs with minimal overhang, no cable on the actual roofline may be required. However, always ensure to create a path for the ice to melt from the roof to the ground, placing cable on the roof, in the gutters, and in the downspouts as necessary. Extend the cable about 1’ out of the bottom of the downspout (surface) or about 1’ below the frost line. As a reference, the frost line in cold areas is typically 20” to 30” deep.
Installing the roof & gutter de-icing cable
The cable laid along the roof line is arranged in a triangular pattern (see Figure 2). The cable MUST extend above the overhang into the warm section of the roof. To determine the height of the triangles, measure the depth of the overhang. The triangle heights are measured by the number of shingle rows from the roof edge (based on the standard 5½ inch tab shingles). Using Table 1, determine the height of each triangle. Using this method, the triangles will extend at least one shingle row (5½ inches) into the warm roof area.
TIP: If you will be working directly on the roof during the installation, you may want to mark the cable pattern with chalk before attaching the cable. If working from a ladder, you will probably want to lay out the pattern as you attach the cable with the clips. Making a drawing of your roof and your planned pattern on paper is recommended.