LEVEL 3 – MEGGER INSULATION TESTING
WHAT MAKES INSULATION GO BAD?
When your plant electrical system and equipment are new, the electrical insulation should be in top notch shape. Manufacturers of wire, cable, motors, and so on have continually improved their insulations for services in industry. However, even today, insulation is subject to many effects which can cause it to fail – mechanical damage, vibration, excessive heat or cold, dirt, oil, corrosive vapors, moisture from processes, or just the humidity on a muggy day.
In various degrees, these enemies of insulation are at work as time goes on – combined with the electrical stresses that exist.
As pin holes or cracks develop, moisture and foreign matter penetrate the surfaces of the insulation, providing a low resistance path for leakage current. Once started, the different enemies tend to aid each other, permitting excessive current through the insulation. Sometimes the drop in insulation resistance is sudden, as when equipment is flooded. Usually, however, it drops gradually, giving plenty of warning,
if checked periodically. Such checks permit planned reconditioning before service failure. If there are no checks, a motor with poor insulation, for example, may not only be dangerous to touch when voltage is applied, but also be subject to burn out.
What was once good insulation has now become a partial conductor.
The Sprint Electrical Team will supply highly-trained technicians to perform Insulation Testing to ensure all components are in proper working order and there are no apparent code violations, as well as hazardous conditions.
