Megger BM121 User Manual

SAFETY WARNINGS
Safety Warnings and Precautions must be read
and understood before the instrument is used.
They must be observed during use.
The circuit under test must be switched off, de-
energised and isolated before Insulation or
Continuity tests are made.
The test push button must not be held down while
connecting the test leads.
During an insulation test, the circuit must not be
touched.
After insulation tests, capacitive circuits must be
allowed to discharge before disconnecting the test
leads.
Test leads, prod and crocodile clip must be in
good order; clean, and with no broken or cracked
insulation.
Replacement fuses must be of the correct size,
type and rating.
MEGGER
®
BM121 and BM122
Insulation & Continuity Testers
User Guide
Guide de l’utilisateur
Gebrauchsanleitung
Guía del usuario
Symbols used on the instrument
Caution: Risk of electric shock
Caution: refer to acompanying notes.
Equipment protected throughout by Double Insulation (Class II).
Equipment complies with current EU Directives
NOTE
THEINSTRUMENTS MUST ONLY BE USED BYSUITABLY TRAINED AND COMPETENT
PERSONS
.

Megger BM121 Specifications

General

Continuity Test Current	200 mA
Power Supply	8 x AA batteries
Operating Temperature	-10 °C to +50 °C
Storage Temperature	-20 °C to +60 °C
Voltage Range	0 V to 600 V AC/DC
Test Current	1 mA
Display	LCD
Test Voltage	500V DC
Continuity Range	0.01 Ω to 1000 Ω

Summary

Safety Warnings and Precautions

General Safety Rules

Read and understand warnings before use; observe during operation.

Test Procedure Safety

Ensure circuit is isolated, use test button correctly, and allow discharge post-test.

Instrument and Lead Maintenance

Check test leads, use correct fuses, and ensure instrument integrity.

Instrument Symbols

Electrical Hazard and Caution Symbols

Symbols indicating risk of electric shock and need to refer to notes.

Protection and Compliance Symbols

Symbols for Double Insulation (Class II) and EU Directives (CE).

Operation and Display Features

Display Indicators

Explains display features like Fuse Ruptured, Low Battery, and voltage/resistance readings.

Instrument Operation

How to switch on, select modes (Continuity/Insulation) using the control button.

Testing Procedures

Preliminary Test Lead Check

Inspect leads visually and check their continuity by shorting.

Continuity Testing

Steps for performing continuity tests, including lead resistance subtraction.

Insulation Testing

Steps for insulation tests, including mode selection, lead connection, and discharge.

Specifications and Environmental Conditions

Insulation and Continuity Specifications

Details ranges, accuracy, voltage, and current for Insulation and Continuity tests.

Operating and Storage Environment

Specifies temperature, humidity ranges for operation, storage, and accuracy.

Instrument Features and Maintenance

Automatic Discharge and Warnings

Automatic discharge of capacitive circuits and warnings for external voltage.

Power Supply and Battery

Details power supply type, battery life, low battery indicator, and replacement.

Fuse Information

Specifies fuse type, rating, and procedure for checking and replacing it.

Technical Information and Support

EMC and Safety Standards

Compliance with EMC standards and safety requirements for double insulation.

Physical Specifications and Cleaning

Details weight, dimensions, and recommended cleaning procedures.

Accessories and Publications

Lists supplied and optional accessories, and relevant publications.

Repair and Warranty Information

Guidance on handling static-sensitive devices, warranty terms, and unauthorized repairs.

Service and Contact Information

Instrument Repair and Spare Parts

Contact details for service and spare parts for MEGGER instruments.

Company and Product Information

Company Contact Locations

Lists contact addresses and phone numbers for AVO INTERNATIONAL and MEGGER SARL.

Product Manufacturing and Trademarks

Information on manufacturing location, design rights, and registered trademarks.