Megohmmeters and Insulation Testers

Megohmmeters and insulation testers apply a DC test voltage across insulation and measure the resulting leakage current, expressing the result as resistance.

Megger, AEMC, Hioki, HT and IET Labs cover this range. Test voltage is the specification that must match the asset: 500 V and 1 kV instruments suit building wiring and appliances, while medium-voltage motors, generators and cable acceptance testing expect 5 kV or 10 kV. Above the simple spot reading, polarisation index and dielectric absorption ratio tests reveal moisture and contamination that a single measurement misses, and step voltage tests expose weak insulation before it fails. Confirm the guard terminal is present if surface leakage needs to be excluded.