The PowerPacT H, J and L-frame circuit breakers are designed to protect electrical systems from damage caused by overloads and short circuits. H and J-frame circuit breakers are available with either thermal-magnetic or Micrologic electronic trip units. L-frame circuit breakers are available with Micrologic electronic trip units only. Shunt trip (MX) trips the circuit breaker when the control voltage rises above 70% of rated voltage. Pulse type = 20 ms or held control signals. AC shunt trips are suitable for ground fault protection when combined with a Class I ground fault sensing element. The coil is designed for continuous operation.