Conducting Secondary Injection Test Set for Circuit Breaker Maintenance

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Circuit breakers are commonly found in homes, industrial facilities and power substations. They can be used to protect the power line from reversal, overload, earth fault, and over current conditions. This protective device is preferred over fuses. These power interrupters can be reset and reused for future use which makes it cheaper because you do not need to replace it every time it trips. However, poor maintenance can damage it, which can cause problems in the power line.


In order to check the effectiveness of a breaker, a primary injection test or a secondary injection test is conducted. Used circuit breakers are best tested using a 
secondary injection test set. This is because primary injection tests a protective device while it is connected to the power line. When the breaker trips, the coils can induce an inductive kickback which can be several thousands of volts. This can effectively shorten the operating life of the protective device. Primary injection is suitable for new circuit breaker installations to test its effectiveness. Secondary injection is safer on used protective devices because it does the test with no power in its contacts.

If you need secondary injection test instruments, you can get them from Protec.  You can choose from a wide selection of tools from popular brands. Call us at 866-352-5550 for more information ontest equipment rental rates.