Megohmmeter
From Infogalactic: the planetary knowledge core
Megohmmeter (sometimes referred to as a megger) is a special type of ohmmeter used to measure the electrical resistance of insulators. Insulating components, for example cable jackets, must be tested for their insulation strength at the time of commissioning and as part of maintenance of high voltage electrical equipment and installations. For this purpose megohmmeters, which can provide high DC voltages (typically in ranges from 500 V to 2 kV) at specified current capacity, are used. Acceptable insulator resistance values are typically 1 to 10 megohms, depending on the standards referenced.
