• Megger

Megger® BM220 & BM223 Series

Insulation & Continuity Testers
Megger BM200 series insulation & continuity testers


  • Combined analog arc/digital display
  • Backlit LCD for reading in restricted light
  • Test lead null facility
  • Hands-free continuity testing
  • Automatic voltage warning and discharge of circuit under test


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.

Both instruments offer hands free continuity measurement with a short circuit current of greater than 200 mA and an open circuit voltage of 5 V.

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.

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The BM220 Series will find applications in electrical contracting, both on domestic and industrial systems, and in site maintenance and service departments. A choice of instruments allows testing to be carried out on circuits with rated voltages up to 1000 V and all instruments may be used on capacitive circuits since, at the end of an insulation test, the circuit under test will be automatically discharged.

The BM220 Series of Insulation and Continuity Testers are ideal for testing transformers, motors, generators, switchgear, domestic appliances, power tools etc., as well as fixed wiring systems. All instruments meet the requirements of most International Standards including VDE0413 Part 1 and BS7671 (the 16th Edition of the IEE Wiring Regulations).


  • Insulation test ranges produce the rated test voltage into a 1 mA load. Testing can be carried out to International Standard requirements.
  • Digital display of insulation measurement up to 999 MΩ on either linear or logarithmic backlit analog arc digital display.
  • Continuity range has 0,01 Ω resolutioand a short circuit current in excess of 200 mA to meet the requirements of International Standards.
  • No need to press the test buttowhecontinuity testing, leaving both hands free.
  • Automatic switch-off after 5 minutes’ inactivity conserves battery life.
  • Microprocessor control of the solid state digital/ analog display ensures that only the correct scale for the range selected is visible, avoiding taking readings from the wrong scale.
  • Automatic voltage detectioavoids accidental contact with dangerously live circuits.
  • Auto zero allows automatic compensatiofor test lead resistance.
  • Buzzer range operates at <5 Ω.

  • Literature
  • Specifications
Insulation Ranges
BM221, BM224 500V
BM222 500V 1000V
BM223 250V 500V 1000V
BM227 250V 500V
Measuring Range:
Digital: 0,01 MΩ to 999 MΩ
Analog: 0,1 MΩ to 1 GΩ
Test Current on load:
±3% of reading ±2 digits up to 10 MΩ ±5% of reading ±2 digits up to 100 MΩ ±30% of reading up to 999 MΩ
Continuity Range:
Measuring Range: 0,01 Ω to 99,9 Ω
Short Circuit Current: 0,01 Ω to 9,99 Ω 210 mA10,0 Ω to 99,9 Ω 21 mA
Accuracy: 0,01 Ω to 9,99 Ω ±3% ±2 digits10,0 Ω to 99,9 Ω ±5% ±2 digits
Automatic Discharge
When the test button is released after an insulation test the item under test will be automatically discharged.
Default Voltmeter
Operates automatically with any range selected in the presence of an AC or DC voltage in excess of 25 V.
Voltage (BM221, BM222, BM223, BM227 only.)
Measuring Range: 25 V to 600 V to 50/60 Hz and DC
Accuracy: 25 V to 450 VAC. to ±1% ±1 digit450 V to 600 VAC to ±2% DC accuracy unspecified.
Voltage Warning (BM224 only)
Symbol flashes on the display and the buzzer sounds intermittently in the presence of more than 25 VAC, VDC
Auto Shut off
The instrument will automatically switch off after 5 minutes’ inactivity. If the instrument is not to be used for several months, it is recommended that the batteries be removed from the instrument.
Battery Type:: 6 x 1,5 V cells IEC LR6 type.Nickel Cadmium rechargeable cells may be used.