Troubleshooting of Primary Injection Test

Condition	Probable causes	Solutions
Circuit breaker trips earlier than expected during primary injection test with either ground-fault inhibit function or thermal-imaging inhibit function enabled.	Ground-fault inhibit function or thermal-imaging inhibit function was not disabled and restarted after circuit breaker tripped during previous primary injection test.	Stop and restart either ground-fault inhibit function or thermal-imaging inhibit function after each circuit breaker tripping event.
Circuit breaker trips up to twice as long as expected when performing primary injection test.	While performing primary injection using either ground-fault or thermal-image inhibit function, interface screen displays communication error. In response ground fault or thermal imaging was re-inhibited without stopping primary injection causing circuit breaker to trip long when long-time segment of time-current curve tested.	Terminate primary injection test completely. Start ground-fault or thermal-image inhibit function and start primary injection test.
Circuit breaker installed with MicroLogic 6.0A, 6.0E, 6.0H or 6.0P trip unit does not trip when performing ground-fault test.	Fault level injected not high enough to cause trip on ground-fault protection. Circuit breaker connected in Modified Differential Ground-fault (MDGF) or source ground return configuration.	Inject higher fault current. Refer to MicroLogic Trip Unit Compatibility to determine if test is applicable to trip units. The ground fault protection function cannot be tested for circuit breakers configured for Modified Differential Ground Fault (MDGF) or Source Ground Return (SGR) protection. These configurations require primary injection testing.

Condition

Probable causes

Solutions

Circuit breaker trips earlier than expected during primary injection test with either ground-fault inhibit function or thermal-imaging inhibit function enabled.

Ground-fault inhibit function or thermal-imaging inhibit function was not disabled and restarted after circuit breaker tripped during previous primary injection test.

Stop and restart either ground-fault inhibit function or thermal-imaging inhibit function after each circuit breaker tripping event.

Circuit breaker trips up to twice as long as expected when performing primary injection test.

While performing primary injection using either ground-fault or thermal-image inhibit function, interface screen displays communication error. In response ground fault or thermal imaging was re-inhibited without stopping primary injection causing circuit breaker to trip long when long-time segment of time-current curve tested.

Terminate primary injection test completely. Start ground-fault or thermal-image inhibit function and start primary injection test.

Circuit breaker installed with MicroLogic 6.0A, 6.0E, 6.0H or 6.0P trip unit does not trip when performing ground-fault test.

Fault level injected not high enough to cause trip on ground-fault protection.
Circuit breaker connected in Modified Differential Ground-fault (MDGF) or source ground return configuration.

Inject higher fault current.
Refer to MicroLogic Trip Unit Compatibility to determine if test is applicable to trip units.
The ground fault protection function cannot be tested for circuit breakers configured for Modified Differential Ground Fault (MDGF) or Source Ground Return (SGR) protection. These configurations require primary injection testing.