Updated on 19 October, 2021
Insulation tester, sometimes called insulation gauge, is a hand-held electric meter that measures resistance and moisture levels in insulation. Megohameter, sometimes called meggers, is an electrical measurement device used to measure the insulation's resistance against static electricity and produce a voltage. Megohameter, introducing a low voltage, high current (DC) charge, measures the resistance to ground and detects faulty or missing insulation that can result in short circuits, arc faults and increased risk of electrical shock or failure. You can use a Megohameter as an insulated conductor test for a variety of insulation materials. Insulation gauges are safe, reliable and convenient to use.
The insulation tester is a simple instrument, consisting of a dial and a small clip-on probe for conducting voltage measuring function. The user inserts the probe into the appropriate point on the fabric, either above or below the area that needs to be measured. Usually, the two points are selected by a rotary control that ensures that the probe is in a fixed position. This simple operation is easy to learn and the meter can normally be read in one or two hours, depending on the material to be tested.
The benefits of a good insulation tester are many, but the most important feature is the accuracy of its measurement performance. There should be no errors in reading, even if it is tested under ideal conditions. Resistance measurement with a insulation tester is best performed with conductors of different gauge and voltage rating. If a high-voltage, low-gauge wire is used, the insulation resistance tester may not give the desired results. It may interpret the measurement inaccurately due to factors such as poor wiring, excessive heat, and moisture content in the wire.
High voltage insulation resistances are often tested in closed systems. High-voltage equipment is usually protected with lead shields, preventing the passage of excess voltage across the shield. The test voltages are often measured on the non-protected sides of the system. In such cases, the ability of the insulation resistances to conduct high voltage can be determined by measuring the test voltages at different locations. In other words, high voltage insulation resistances require both high and low-voltage methods to determine their suitability.
Some insulation tester machines measure resistance directly, while others rely on an analog technique called capacitance measurement. Capacitance is a type of measurement that involves the application of an electric field across a conducting media. The applied electric field varies depending on the orientation of the media and the degree of orientation to the electric field. Some widely used insulation resistance testing machines use digital models.
To determine whether the equipment has a good insulation value or poor insulation quality, a measurement called resistivity must be performed. Resistance is the product of the thickness of a material against a chosen voltage. If resistivity is high, then the machine has good insulation quality. It is possible to check resistivity directly using a multi meter but it is better to obtain electrical test equipment ratings and inspect the machine before purchase.
In addition to resistivity, insulation tester machines may also perform other resistance tests. They can measure integrated circuit failure points, thermal expansion, and electrical conductivity. High voltage insulation testers commonly measure these four parameters. Other resistance tests include overload and short-circuit tolerance, which are important for electronic and electrical equipment applications.
Many construction companies that rent electrical testers use multi meter testers with integrated circuit testers, overload and short-circuit tolerance, and other useful tests. These construction equipment testers usually come in sets of eight, nine, or ten, depending on the size of the project. They are portable and are quite user friendly. Each of these different types of testers has its own advantages and disadvantages. Each type of insulation tester is priced differently.