If a parallel electric heating tape fails, how do you determine the fault point?

Heating cables offer excellent heating performance, especially constant-watt parallel-type heating cables, which can be used not only for general heating and insulation applications but also for complex environments, such as explosive atmospheres in factory zones 1 and 2.

If a heating cable fails during use, such as a parallel-type heating cable, how can we determine the fault point? First, you can split the cable into two sections. At this point, the fault point is still difficult to pinpoint; it could be in the front or back section. Further confirmation is required. Once the front section is identified, you can further narrow the scope by splitting it in two. This process can ultimately pinpoint the fault point.

For example, if a section of pipeline is covered with 50 meters of heating cable and cannot be powered on for maintenance, the following steps can be used:

1. Verify that the circuit breaker, cables, and thermostat in the distribution box are functioning properly before locating the fault point in the heating cable.

2. Remove the metal sheet and insulation from the thermostat and terminal junction box, and remove the heat-resistant tape and aluminum tape. Also remove the thermostat and terminal.

3. At approximately 25 meters, remove the metal sheet and insulation, and remove the heat-resistant tape and aluminum tape to fully expose the heating cable. Peel back approximately 250cm of the outer insulation (i.e., the reinforcing sheath) from the heating cable and cut the braid. Be careful not to damage the insulation (i.e., the outer sheath) of the heating cable.

4. Wrap the cut braid with insulating tape. Then, use an insulation resistance meter to clamp either busbar and the braid at the thermostat (or tail end) to test the insulation performance. (Use a 2500V insulation resistance meter.) Assuming the insulation is abnormal between the thermostat and the center disconnect (25 meters), but normal between the tail end and the center disconnect, the fault is determined to be within the 25 meters between the thermostat and the center disconnect. Connect the cut braid and wrap it with insulating tape.

5. At approximately 12 meters from the heating cable, remove the insulation and tape, peel back the insulation by about 250cm, and cut the braid.

6. If the fault is determined to be within 10 meters of the heating cable, remove the insulation and repair it.