Tech Tips: How to Test Self Regulating Cables
In this video, our tech lead Scott shows you how to test a self regulating cable - these systems are used for deicing roofs, gutters and outdoor pipes with radiant heating.
Using an electrical megaohmmeter, you should test the cable before, during and after installation to make sure the product is in working order.
Hello. When you order your self-regulating cable for installation in your gutters or on your roof, it will arrive in a spool. The end of the cable will typically be cut off, leaving it nondescript and without any visible indication of its internal components. Before proceeding with the installation, it is crucial to test the cable to ensure its functionality. To do this, you will need to disassemble the cable to examine its internal structure.
Upon inspection, you will find that the cable is encased in an outer cover made of a plastic-like material. Inside this cover, there are two metal components known as bus bars, along with a ground wire. By carefully removing the outer layer, you will expose these internal elements. This process involves trimming back the cable a couple of inches and separating the ground wire. You will then need to remove an additional layer of insulation, which will reveal the black inner core and the two wires that conduct electricity.
To verify the integrity of the cable, you will require a mega ohm meter. This device may come in various forms, including older crank models, though it is advisable to use modern battery-powered electrical mega ohm meters. The purpose of the mega ohm meter is to perform a high potential insulation test, ensuring that there is no continuity between the conductor and the ground. To conduct the test, set the meter to the 500-volt selection and connect the probes to the respective wires.
Using both hands, attach one probe to one of the wires and the other probe to the ground. It is essential to exercise caution, as this involves high voltage. After conducting the test, the meter should indicate infinity, confirming that there is no connectivity between the outer braid or ground and the inner core. Repeat the process for the other wire, ensuring that you receive the same infinity reading. If both tests confirm no contact with the ground, you can conclude that the cable is in good condition and ready for installation.
