As the insulation resistance quality on an electrical system can degrade over time – whether it’s from heat, cold vibration, dirt or similar forces, it becomes very necessary to check the insulation resistance of equipment at a constant regular interval. Routine testing, where Megger test equipment is used to test electrical insulation, will keep you in the know whether or not your electrical systems are performing as effectively as you are expecting to. By regularly testing the insulation, many problems can be identified and fixed before an accident or equipment failure occurs. But in order to select the best insulation resistance tester for your purpose, you will have to consider a few different factors.
First things first, ask yourself what kind of electrical systems do you need to test. Have in mind the nominal voltage of the equipment that you need to check and approximately how many tests per year there need to be conducted. The nominal voltage can help you decide which test voltage you will need from an instrument, while the number of tests you perform each year will help you determine whether extra convenience features are important or not. Generally speaking, when there are more tests that need to be conducted, the overall quality, durability, and convenience become more important.
Another thing that you need to consider is the test environment and other possible uses for the insulation resistance tester. This will also help you when selecting additional features. Ask yourself where will the test instrument be used – is it only going to be used in a shop environment or in an industrial plant or will it be used inside or outside. Some insulation resistance testers can be relatively large and not very portable, while others can be easily carried. For instance, a Megger test equipment that is built into a robust, lightweight case, will be light enough to be worn around your neck but also suitable for field, production or test laboratory use. Also when small in size it can be taken into areas that are otherwise too small to access.
Also, you want to make sure you choose an insulation resistance tester that will supply the needed output test voltage. That’s because not all insulation resistance testers are the same. For instance, many handheld insulation testers can supply test voltages up to 1000 volts, while others may supply 5,000 V dc test voltage or even more.