Introduction to Electric Heat Tracing Cable
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When the electric heating cable is powered on (note that the core wires at the end must not be connected), current flows from one core wire through the conductive PTC material to the other core wire, forming a circuit. The electric energy heats the conductive material, and its resistance increases accordingly. When the core temperature rises to a certain value, the resistance becomes so large that it almost blocks the current, and the temperature no longer rises. At the same time, the electric heating cable transfers heat to the lower-temperature heated system. The power of the electric heating cable is mainly controlled by the heat transfer process, automatically adjusting the output power according to the temperature of the heated system.
Features of Electric Heat Tracing Cable
1. Cable structure: inner layer of conductive thermoplastic, outer layer of double-layer flame-retardant polyolefin with shielding layer
2. Temperature range: maximum exposure temperature 85°C, maximum surface temperature 85°C
Maximum maintenance temperature 65°C, minimum operating temperature -60°C
3. Installation temperature: minimum: -5°C
4. Thermal stability: after 300 cycles between 10°C and 99°C, the cable heat output remains above 90%.
5. Bending radius: 25.4mm at 20°C room temperature, 35.0mm at -30°C low temperature
6. Insulation resistance: for a cable length of 100m and ambient temperature of 75°C, tested with a 2,500VDC megger for 1 minute, the minimum insulation resistance (between conductor and shield) is 120MΩ.
7. Starting current (10°C): 0.4A per meter
8. Installation and use as per the diagram on the back
9. Maximum use length: not exceeding 100 meters
Precautions for Installation of Electric Heat Tracing Cable
1. During laying, do not kink, do not subject to excessive tension, and avoid impact hammering to prevent damage to insulation and short circuits. During installation, no welding, hoisting, or other operations should be performed above the installation area to prevent welding slag from splashing onto the heating cable and damaging the insulation layer. Confirm that the pipe or equipment to be heat traced has been leak tested and cleaned, and that surface burrs and sharp edges have been smoothed and polished.
2. When laying in a winding manner, do not exceed the minimum bending radius of the cable (minimum bending radius not less than six times the cable thickness). Excessive bending or folding may cause local molecular structure changes, leading to breakdown and fire.
3. The cable should be tightly attached to the pipe surface to facilitate heat dissipation. Fix the cable with aluminum foil tape to increase the heat dissipation area, which is beneficial for heat conduction and also convenient for installation. The method is: first clean the oil and moisture on the cable path, fix the heating cable radially with fixing tape, then lay and cover with aluminum foil tape, and finally press firmly with a cloth to make the cable adhere smoothly to the pipe surface.
4. The installation of insulation and waterproof layers must be carried out after the cable installation and commissioning. The insulation material must be dry; damp insulation material not only affects the insulation effect but may also corrode ordinary heating cables, shortening their service life. After installing the insulation material, the waterproof layer must be wrapped immediately; otherwise, the insulation performance will be reduced, affecting the normal operation of the heat tracing system.
5. The installation length of the cable should not exceed its "maximum allowable use length". The maximum allowable length varies with different product models.
6. When wiring shielded cables, in addition to the reliable grounding protection of the medium pipeline system, the braided layer should be connected together, and reliable grounding should be installed. The conductive core wires at the cable ends must not contact the shielding mesh.
7. The cable end should be sealed with an end junction box. Do not connect the two parallel wires to avoid short circuits.
8. The junction box must be firmly fixed to the pipe wall to avoid short circuits caused by firearms and resulting flooding.
Note: The above information and technical parameters are compiled and published by Yangzhou Darry Electric Co., Ltd.
