The Megger® BM400/2 Series of autoranging insulation and continuity testers, provides simplicity of use in a hand-held instrument, which fully complies with British and International Wiring Regulations. The ease of use and comprehensive specifications are achieved using the latest electronic design and display technology.

The Analog/digital LCD incorporates the benefits of electronic arc Analog indication with unambiguous digital readings. The Analog scale helps to make rapid identification of insulation condition, and to monitor variable readings, and is complemented by the precision and simplicity of a digital display.

The series offers a range of single, dual and multi-voltage variants to suit the user’s application. Each range conforms to BS 7671 (formerly the 16th Edition IEE Wiring Regulations) and International standards IEC 364 and HD 384. The insulation ranges output the nominal test voltage when loaded with 1 mA as specified within these standards. The continuity ranges have a short circuit test current of at least 200 mA in order to comply with the requirements of European harmonisation and international documentation. Also, the hands free continuity ranges have the facility to null the resistance of the test leads enabling direct readings of low resistance to be taken. A continuity buzzer is included on the second continuity range.

In addition to the insulation and continuity ranges, the BM400/2 series has a resistance range which measures up to 100 k½ on the digital scale and up to 10 M½ on the Analog scale. Due to the low test voltage and current of this range, it can be used to test circuits with sensitive equipment connected, without causing damage.

Two voltage ranges measure up to 50,0 V and 600 V a.c. or d.c. respectively, and indicate the presence of negative d.c. A voltage warning is provided in these models, alerting the user to the presence of external voltage greater than 25 V, by displaying the voltage level, even when measuring on insulation and continuity ranges. The voltage range will indicate if capacitive charge remains after a test, and will monitor the automatic discharge. Two non voltage-measuring models (BM402/2 and BM404/2) are available which generally precludes the use of fused test leads. To alert the user of the presence of external voltage, the non-voltage measuring instruments (the BM402/2 and BM404/2), will emit a beep and the Analog arc and ‘V’ symbol will flash. On all models testing is inhibited if 55 V is detected. Hands free operation is offered as standard on all ranges except the insulation ranges. Locking and non-locking test buttons are provided with each instrument for user selection. Use of the non-locking button is recommended to prevent accidental mis-use and injury, and in cases where continuous operation of an insulation test is required the locking button can be fitted. Alternatively the optional accessory Switched Test Probe SP1 can be used enabling remote operation of the test button from the negative test probe.