The Megger® BM220 series of Analog Arc/Digital Insulation and Continuity Testers comprises a range of instruments which offers comprehensive test features in a cost effective package.
Combining an Analog arc with a clear 3 digit LCD, the instruments offer a choice of insulation test voltages, with the option of single, dual or triple test voltage instruments. A selectable backlit display is incorporated to ensure readings may be taken in low light areas such as distribution boards or enclosures.
All instruments detect inadvertent connection to a live system which is energised to greater than 25 V. Dependent on model, the instruments either switch to the default voltmeter or indicate the presence of voltage by beeping and flashing the display.
Under this condition an insulation or continuity test cannot be carried out and the instrument will therefore automatically inhibit any further action until the source of voltage has been removed. Although insulation tests should only be carried out on de-energised systems, the instruments are protected on all ranges against accidental connection to phase to earth voltages up to 300 V a.c. and phase to phase voltages of 400 V a.c., Installation Category III.
Further indicators illuminate to show a low battery state and if the protective fuse has ruptured. To avoid accidental use of the 1000 V range, an indicator flashes for 3 seconds when the range is selected giving a visual warning. The instruments will automatically shut down after 5 minutes of non use to conserve battery life.