Cold Weather Catalog - Chromalox Precision Heat and Control

Heating CableSRF-RGSelf-RegulatingRoof & Gutter• Roof and Gutter De-Icing• Fast, Easy Installation• Cut to Length• UL Listed• CSA Certified• Approximate Size 3/8"W x 1/8"H• Minimum Bend Radius 1-1/8"DescriptionChromalox SRF-RG self-regulating heatingcable provides reliable freeze protectionof roofs and gutters. Because SRF-RG isself-regulating, it automatically adjusts to theappropriate heat output as ambient conditionschange, making it both energy effi cientand cost effective. The protective waterproofouter jacket is suitable for wet applications indownspouts and roof drains.Likewise, it is easy to apply SRF-RG followingthe provided instruction sheets and utilizingthe required accessory kits. It can be cut-tolengthand overlapped. Simply trace the gutteror roof and energize the cable when precipitationis expected. From that point on, SRF-RGwill rapidly increase its output when in contactwith snow or ice, providing maximum meltingpower. When the roof and gutters are clear ofsnow and ice, the SRF-RG cable will regulateits output and save energy.ApplicationsBCut to Lengthin Field1. To calculate the amount of cable needed,multiply roof edge length to be heattraced by the spacing factor. The spacingfactor (feet of cable required per footof roof edge) is determined by the roofoverhang, heating width (A) and heatingheight (B):2. Add the total gutter length and the totaldownspout length to the fi gure calculatedin step 1 to get the total length of cablerequired.AOutputTemperatureSelf RegulatingOutput3. Determine how many circuits are required.Divide the total length of cable by themaximum circuit length (see specifi cations,next page). Round that number up (forexample, 2.1 to 3) to get the total numberof circuits.WARNING — A ground fault protection deviceis required by NEC to minimize the danger offi re if the heating cable is damaged or improperlyinstalled. A minimum trip level of 30mA isrecommended to minimize nuisance tripping.RoofOverhang(In.)HeatingWidth A(Ft.)HeatingHeight B(In.)SpacingFactor12 2 18 224 2 30 336 2 42 4For larger roof overhang, determine cablerequired by using equasion below:Spacing factor = B 2 + A 2110