In high-current electrical systems, even a few micro-ohms can make a big difference. That’s why contact resistance testing has become a fundamental part of preventive maintenance for switchgear, circuit breakers, and busbar assemblies. It detects issues that visual inspections often miss—before they lead to overheating, energy loss, or catastrophic failure.
A contact resistance tester injects a high DC current—often 100 A or more—through the electrical connection while simultaneously measuring the voltage drop. Using Ohm’s Law, the device calculates resistance with extreme precision. The lower the resistance, the better the contact integrity.
Elevated contact resistance usually indicates one of three problems: corrosion, loose or degraded connections, or mechanical misalignment. These conditions increase heat generation at the contact interface, which can accelerate aging, trigger protection relays, or, in worst cases, cause arc faults.
Routine contact resistance testing is especially important in aging infrastructure or outdoor switchgear where moisture and environmental contamination are common. It’s also a critical step after breaker servicing, ensuring that all joints and contact points are reassembled properly and seated correctly.
Today’s portable contact resistance testers are rugged, battery-powered, and equipped with Kelvin (4-wire) connections for maximum accuracy. Many models include built-in data logging, automatic temperature correction, and pass/fail thresholds to speed up decision-making in the field.
If your maintenance strategy still relies on visual checks alone, you’re missing the full picture. A contact resistance tester gives you quantifiable evidence of contact quality—and that means greater confidence in every connection.
