Secondary current injection testing is performed on solid-state trip units using a specially designed power supply unit. However, the secondary injection method only tests the solid-state trip unit, and does not test the current sensors, wiring, or the breaker current handling components.
A secondary injection test set allows for the inspection of the solid-state trip unit operation without using primary current by passing enough current to check any desired calibration point. The breaker must be de-energized before checking the operation of the solid-state trip units.
The primary current injection method is favored when it is necessary to verify the sensors and wiring, as well as the conduction path in the breaker. It is recommended that the primary injection test be performed on all three phases when testing breakers with solid state-trip units.
Related electrical test equipment available for rent from Protec: