The LRM 200 is a microprocessor-based, true DC micro ohmmeter designed to test the contact resistance of circuit breaker contacts, switchgear, and bus bar joints. It is the instrument every test technician needs to have to maintain circuit breakers, switch gear and busbars. The LRM 200 is designed to meet the IEEE C57.09-1999 standard’s requirements for testing circuit breaker contact resistance.
The LRM 200’s wide measuring range is 1 micro Ohm to 5 Ohms with 0.1 micro ohm resolution with a current range of 10 A to 200 A.
The LRM 200 injects a true DC current through the contacts under test and measures the contact resistance. It can compare the test results against the prescribed limit and make the pass/fail decision. As the rise and fall time is configurable for each test, no transients are induced in the associated apparatus such as current transformers. This avoids tripping of the relays. The LRM 200 is a lightweight (15 Lbs/7.5 kgs) instrument designed for portability and field use.


Dual Ground Connections
- Outstanding Features
- Technical Specifications
- Downloads
- Selectable rise and fall time of the true DC current eliminates the mal-operation of connected relays to the current transformer
- “Fast Test” mode to check multiple contact joints in the current circuit, improving productivity
- Full-size keyboard, color display and built-in thermal printer with user friendly interface for efficient and quick testing
- Internal Storage of 150 test records with 75 readings each, along with nameplate details, eliminating the need for a computer
- Ability to export test results to PDF and Excel format
Physical Specifications | Dimensions: 18”W x 7”H x 15” D (45.7 cm x 17.8 cm x 38.1 cm) Weight: 19.8 lbs. (8.9 Kg) |
Resistance Reading Range | 1 micro-ohm to 5 ohms (max 10 milliohms @ 200A and 5 ohms @ 1A) |
Test Current Range | 1A ¬ 200A (selectable in 1A steps) |
Resolution | 0.1 µΩ - 999.9 µΩ: 0.1 µΩ 1.000 mΩ - 9.999 mΩ: 1 µΩ 10.00 mΩ - 99.99 mΩ: 10 µΩ 100.0 mΩ - 999.9 mΩ: 0.1 mΩ |
Typical Accuracy | ±(0.15% of reading + 0.15% FS) at test current of 10-200 A |
User Interface | Screen: Back-lit LCD color screen (800 x 480 pixels) viewable in bright sunlight and low-light Keypad: 44-key "QWERTY" back-lit keypad Printer: Built-in 2.5” thermal printer |
Computer Interfaces | One USB PC interface One USB flash drive interface |
PC Software | Windows®-based analysis software is included |
Internal Test Record Storage | 150 test records; each record can contain up to 75 readings |
Input Power | 100 - 240 Vac, 50/60 Hz |
Temperature | Operating: -10°C to +50°C (+15°F to +122°F) Storage: -30°C to +70°C (-22°F to +158°F) |
Humidity | 90% RH @ 40°C (104°F) non-condensing |
Altitude | 2,000 m (6,562 ft) to full safety specifications |
Included Cables | 33 ft (10 m), #1 AWG test cables, power cord, ground cable, USB cable |
Safety | Designed to meet IEC 61010 (1995), UL 61010-a, and CAS-C22.2 standards |
Options | Shipping case, 15 ft (4.57 m) test cables, hand spike set, dual ground option |
Warranty | One year on parts and labor |