Contact resistance testing solutions

Get the fast, stable results you need in the field. Megger’s micro-ohmmeters deliver reliable, high-current contact resistance testing across circuit breakers, switchgear, and busbar systems.

When resistance rises, so does the risk. Even a slight increase can cause excessive heat, energy loss, equipment damage, or failure. That’s why it’s important to detect poor electrical connections early, so your systems continue operating safely and efficiently by staying within acceptable values and parameters.

Megger’s low resistance meters give you the confidence to act before problems escalate. Whether it’s degraded main contact surfaces, loose joints, corrosion, or aged materials, our instruments detect both steady-state and dynamic resistance with precision including applications such as a busbar contact resistance tests in switchgear and distribution systems.

Designed for use on circuit breakers, busbar connections, connectors, and other critical joints, our meters help you pinpoint weaknesses by testing that values are in acceptable limits, so you can carry out preventative maintenance and avoid costly downtime.

With Megger, you’re not just testing connections—you’re protecting your entire operation.

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Prevent Failures Before They Happen

Rising contact resistance is one of the earliest warning signs of electrical failure — long before there’s visible damage or a breaker trips. With Megger’s contact resistance testing solutions, you can quickly identify main contact wear, corrosion, or poor connections and take targeted action before faults occur. That means fewer surprises, less downtime, and complete confidence in the reliability of your breaker fleet.

Confidence in Every Reading

When you’re working in high-noise environments or dealing with extremely low resistance values, there’s no room for doubt. Megger’s contact resistance tests deliver fast, stable, and repeatable results — even in the micro-ohm range — so you know exactly what’s happening at the connection point. Whether you're confirming breaker integrity, testing acceptable resistance values, or spotting early signs of failure, you get reliable data you can act on, first time, every time.

Fast, Accurate, Repeatable Results

Every second counts when you're testing multiple assets under pressure. Megger’s contact resistance testers combine high output current, rapid stabilisation, and advanced filtering to deliver precise results in seconds — not minutes. You get consistent micro-ohm accuracy across tests, even in noisy environments, so you can move fast without compromising on quality or confidence.

Ready for the Real World

Whether you're working in a cramped panel room or a remote substation, you need contact resistance test equipment that works with you — not against you. Megger’s low resistance meter range includes everything from compact handheld units to high-current field instruments, all designed for quick setup, simple operation, and reliable performance in tough environments. Rugged, portable, and built to last — these are tools you can depend on, wherever the job takes you.

Frequently asked questions

What applications need low resistance testing?

Low resistance testing is used across many industries to verify the integrity of critical connections. Common applications include:

Utilities and contractors – testing breaker contacts, busbars, cable joints, and bonding points during commissioning and maintenance

OEMs – production testing of breakers, high-voltage switchgear, and welded joints

Transport and rail – checking ground connections, bonding, and conductor rail continuity

Aerospace – verifying aircraft frame bonds and static control paths

Anywhere a poor connection could cause heat, loss, or failure — low resistance testing is essential.

What type of instrument should I use for measuring circuit breaker contact resistance?

Contact resistance test values are typically in the tens to hundreds of micro-ohms — too low for standard ohmmeters. You need a four-wire (Kelvin) tester to eliminate lead resistance and deliver accurate results.

Standards require high test currents:

IEC recommends 50 A or more

IEEE recommends 100 A or more

Choose an instrument with a smooth DC output, current ramp-up/down control, and, ideally, DualGround™ capability for added safety when testing both sides of the breaker remain earthed.

What is a 'good' or acceptable contact resistance value for my circuit breaker?

There’s no single “correct” value — it depends on the breaker type, size, and manufacturer specs.
However, consistency is key:

Look for stable, repeatable results

Watch for sudden increases over time — they could indicate contact wear, corrosion, or looseness

Compare phases and poles — large deviations often signal a problem

Always refer to the manufacturer’s guidelines and baseline test data where available, including the specified acceptable values for the contact resistance test or equivalent criteria.

What is the reason to use highest possible current to measure the contact resistance?

Higher current improves measurement accuracy and helps confirm acceptable test values by:

Overcoming surface oxidation or film resistance

Stabilising the reading in inductive circuits

Matching real operating conditions for breakers and busbars

High current also helps meet compliance standards and improves confidence in the test result — especially in critical power infrastructure.

Need Reliable Contact Resistance Testing?

Get expert advice on the right solution for your application — whether it’s routine maintenance, commissioning, or production testing. Our team is here to help you choose the best tool for the job.

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