Breaker Testing: All about circuit breaker testing solutions

There is a range of breakers in our life, and they are a helpful component in any electrical device. They can help maintain order and add a layer of safety to the electrical power system. However, when put in use, the condition of circuit breakers deteriorates. Besides the half-life, some other correlated factors, such as varying load, load removal, and addition, circuit alteration, improper or inappropriate device selection,  also lead to deterioration. Luckily, with the beaker testing, we can ensure proper operation, reduce damage to circuit breakers, increase conditions for circuit breakers, and above all save a life.  And, according to circuit breaker types, you can keep routine maintenance and testing with different circuit breaker testers. Now, read on to find the circuit breaker testing method.  

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Recommended Circuit Breaker Tests

Circuit breaker testing services are plenty depending on the type of circuit breaker and operation types. The comprehensive circuit breaker tests include;

Offline Testing:

These kinds of circuit breaker testing supplies are:

Capacitance and Tan Delta Measurement

Capacitance and tan delta measurement help verify the insulation of components used in the circuit breaker.

Insulation Resistance Measurement

The resistance test by the direct current can address several issues like contamination, moisture, and mechanical failure. It checks the threshold for the other tests too.

Insulation Resistance Measurement

Dynamic Contact Resistance Measurement (DCRM)

The duration and the distance by which currently carries measure dynamic contact resistance measurement (DCRM), during which the circuit breaker contact acts like an SF6 puffer type. The application of this test is simple, where the circuit breaker operates through the contact points with a small DC. We then measure the resistance using the change in the contact position by doing simultaneous records. DCRM can also help measure the length of the arcs of current, whereas in other cases, only dismantling the circuit breaker is the only option. The material used at the contact point is copper/tungsten, which melts when a high current passes.

Static Contact Resistance Measurement (SCRM)

This test extends like DCRM where you insert circuit breaker contacts with a small DC but at the closed circuit. You can confirm the results by checking the resistance against drops in the voltage. The resistance indicates the condition of the contacting part.

Static Contact Resistance Measurement (SCRM)

Timing Measurement

Time measurement is significant as slight time delays can affect the operation of the circuit breaker. Thus, you have to take the time measurement with the change in the resistance state and main contacts with aux contact as an independent time state. You can also get related data like dead-time, dwell time, velocity, and circuit distance.

SF6 Gas Dew Point Measurement

Dew point temperature is when water vapors around the circuit breaker condense to form a liquid. This negligence can cause flashover and corrosion in the circuit breaker which can hamper the mechanical performance. So, for this purpose, you have to keep the moisture content inside SF6 at the least possible.

SF6 Gas Leakage Test

During the conventional times, you had to sniff for the SF6 gas leakage. But today, we can use leak detectors or sniffers to perform this operation. This leakage may occur at joints like flanges, bushing, and valves. It can occur due to tank leakage, which is most rare.

Vacuum Interrupter Test (VIDAR- Only For VCB)

Air pressure drop can estimate the measuring of the air pressure at various operations, like in the case of air-blast breakers.

Functional Check (Remote Trial)

This is the final check before giving the green signal for mass production or packaging. You use the short-circuits to check the behavior by switching time with little oscillogram readings after arc dissipation and contact breakage.

Online Testing:

Here are a few of them:

Partial Discharge Measurement

You can take partial Discharge Measurement using testers, where the voltage spike shows oscillation. The voltage is of the order mV to few volts and is equal to the discharge current. On the other side, the discharge is estimated in Columbus. PD takes the readings relative, not absolute, so you have first to decide the reference. The oscillations fluctuate between the measurement location and discharge site. These fluctuations depend on many factors like frequency of motors, range of PD. Although it gives you relative results, it is still helpful for detecting early warning and wear.

artial Discharge Measurement


Thermography means using images to detect the component wear condition. In case of a temperature increase, the connection can get loose and worn bearings. With this technique, the heat distribution pictures help locate the possible current faults which can arise in the future. This is a non-destructive test, and you can perform it at any time without production delays.

How to Test a Circuit Breaker With Breaker Test Equipment?

The circuit breaker testing tool is:

A circuit breaker analyser

Due to electrical overload, a damaged or broken circuit breaker can elevate that chance. In some cases, it might even cause a short circuit or fire. The circuit breaker analyzer operates on fault current condition, which calculates the voltage, current, and related parameters through a set of algorithm diagnostics after finishing the test under various conditions.

A micro – ohmmeter

A micro-ohmmeter can test the working conditions of the circuit breaker. It can gauge the resistance to the amount of following current, which results in an electrical discharge.

Breaker Testing– A high current primary injection testing tester

For the regular checks for overload and faults, the low voltage test should pertain. You can use primary current injection testing for this purpose, too, for current transformers and related devices. This helps us verify the electrical distribution of the system. For this setup, experts recommend static trip devices. You can use a custom wiring harness to mold it according to your requirements and application. 

A high current primary injection testing tester

Breaker Testing– A secondary injection test set

The Secondary current injection uses the power supply units which are designed for this purpose. For each test, you can use a wide injection range. For example, the checking of trip units uses solid-state units with the help of primary current. You do this testing with the closed circuit, whereas this helps you understand if the solid-state is functioning, it is not the trip unit that needs replacement.

Breaker Testing– A Multimeter

A multimeter is very helpful if you are interested in narrowing down your instrument and using a voltmeter and ohmmeter in one device. It can help test circuit breakers using many injections and functions. We can check the continuity, voltage, and resistance in the circuit through it. This quick method can give a quick result for speedy recovery and procedures.

Breaker Testing– A Clamping Ammeter

The biggest issue with the circuit breakers is that they tend to rest whenever used. This can make the diagnosis more cumbersome. Hence we use a clamping ammeter. This can help you in checking the overloads and shorts circuits in the components and devices. You can also measure the electric current through the circuit. Like in the case of ammeter, this connects in series only with a single wire. A positive clamp ammeter shows the short circuit or overload without hassling in finding the error in the components.

Breaker Testing– An Electromagnetic Circuit Finder

In most cases, it sometimes looks as if the circuit still carries the current even after tripping. This is very dangerous as you’re left with nothing when this situation arises. Thus, for this purpose, we use electromagnetic circuit finders. Although it is not accurate every time still it can give a fair idea of the electromagnetic field. Otherwise, you can also use a more expensive tester to get more accurate results; you get the actual purpose of using this tester.

Breaker Testing– An Electrostatic Wand

The stick, which refers to the electrostatic wand or volt stick, can state if the wire or the insulation around the wire overheats during DC. In case of an anomaly, it will state with the light indicator. This tester is inexpensive but not reliable, as it may catch stray signals from the environment and corrupt the actual results.

Breaker Testing–A Voltmeter

The voltmeter is considered the oldest, yet it can give the best results when a large amount of current is being passed. The circuit breakers may give irregular results using the inexpensive testers. This tester helps measure the live voltage by connecting the probes with the neutral and live wires of the circuit breaker. The downside, this voltmeter uses shunt resistance in its operation, not guaranteeing whether the current will completely pass through it, is not possible.


All in all, choosing proper breaker test equipment depends on the type of breaker a lot, such as vacuum circuit breakers, voltage circuit breakers, and so on. Also, besides replacing a bad circuit breaker, you also need great quality wire harnesses to provide additional safety. Interested? Check out our website to get more information about circuit breaker troubleshooting.

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