Electric heating of paved surfaces such as sidewalks, driveways, and parking ramps is an efficient, economical method of preventing snow and ice accumulation. Electrical snow melting systems replace older, less efficient means of snow removal such as hot water or oil circulation systems, plowing or shovelling, and offer an effective alternative to the application of salt and other chemicals which results in pavement damage and environmental pollution.
MIC mineral insulated cable is a high performance, industrial quality, series resistance heating cable which uses a high temperature metallic conductor as the heating element. The conductor is insulated within an organic dielectric, Magnesium Oxide (MgO). The cable has a corrosion resistant incoloy 825 outer sheath which provides mechanical protection and a metal grounding path. Because of the superior performance of MIC cables, snow melting designs can use these advantages to reduce the overall cost and improve the reliability of the snow melting system.
MIC cable has been used for snow melting systems for over 40 years, and offers several advantages over parallel, self regulating heater technology when used for snow melting systems.
Constant Wattage: MIC cable provides a series resistance heating system so that the power output is uniform over the entire length of the cable. Parallel, self regulating heaters develop a significant voltage drop over their circuit length which results in reduced power output at the end of the circuit.
High Voltage: MIC cable can be operated up to 600 volts while parallel, self regulating heaters are limited to 347 volts. Increased voltage results in longer circuit lengths and fewer circuits. In addition, increased voltage correspondingly reduces amperage for an overall reduction of power distribution costs, and, at higher voltage, the need for step down transformers can be eliminated.
No Inrush: MIC cable eliminates oversizing of circuit breakers because of cold temperature inrush. Most MIC cable do not exhibit cold temperature inrush, and circuit breakers are sized for steady state load. Circuit breakers for parallel, self regulating heaters must be over-sized to compensate for inrush.
High Power: MIC cables can be operated up to 88 watts per foot (289 w/m). Because of the superior performance capabilities of MIC cable, power outputs can be increased, which reduces the amount of cable necessary for the required watt density. Parallel, self regulating cables are limited to 30-35 watts per foot (100-115 w/m), which results in narrower spacing and increased heater quantities.
Rugged Sheath: MIC cables have a rugged, Incoloy 825 outer sheath which resists mechanical damage during installation. Parallel, self-regulating heaters have plastic sheaths which are easily damaged during installation.
High Temperature Exposure: MIC cables can withstand high temperatures, a requirement for installation in asphalt. Parallel, self-regulating heaters are damaged by these temperatures.
Conduit Installation: MIC cables can be installed inside conduit without deration of the heater. No additional cable is required if the cable is installed in conduit. Parallel, self-regulating heater power output must be derated as much as 40% if installed in conduit, which increases the amount of cable required.
Design Options: MIC cables are available in a wide variety of resistances and with either one or two conductors. More design choices allows the designer to provide the most economical heating solution, taking many design variables into consideration, such as circuit length, voltage, and power distribution requirements. Parallel, self-regulating heaters are limited to only one or two cable choices, with few options for design.
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