DOCA0095EN

Responding to a Powerpact B Circuit Breaker Trip

Taking Precautions Before Responding to a Trip

DANGER
HAZARD OF ELECTRIC SHOCK, EXPLOSION, OR ARC FLASH
  • Apply appropriate personal protective equipment (PPE) and follow safe electrical work practices. See NFPA 70E, CSA Z462, NOM-029-STPS, or local equivalent.
  • This equipment must only be installed and serviced by qualified electrical personnel.
  • Turn off all power supplying this equipment before working on or inside equipment.
  • Turn off all power supplying the downstream equipment by manually opening the circuit breaker.
  • Before working on or inside equipment, always use a properly rated voltage sensing device to confirm that power is off.
  • Replace all devices, doors, and covers before turning on power to this equipment.
  • Beware of potential hazards, and carefully inspect the work area for tools and objects that may have been left inside the equipment.
Failure to follow these instructions will result in death or serious injury.

Before inspecting electrical equipment downstream of the protection, always isolate the feed.

Identifying the Cause of the Trip

A trip can be caused by the following events:

  • Fault detection on the installation

  • Fault detection caused by malfunction

  • Intentional tripping

Check the circuit breaker and the electrical installation to find the root cause of the trip.

Checking Equipment After a Trip

CAUTION
HAZARD OF CLOSING ON ELECTRICAL FAULT
Do not close the circuit breaker without first inspecting and, if necessary, repairing the downstream electrical equipment.
Failure to follow these instructions can result in injury or equipment damage.
NOTE: Checks, tests, and inspections must be carried out by qualified electrical personnel.

The fact that the protection has tripped does not fix the cause of the fault detected on the downstream equipment.

Perform the following tasks after a short-circuit:

  • Carefully clean off any traces of black smoke. The smoke particles can conduct electricity.

  • Check the power connections and control wires.

  • Operate the circuit breaker at least five times at zero load.

Depending on the type of fault detected, perform the following inspections on all or part of the equipment where the fault occurred (see List of Checks and Inspections):

  • For faults tripped by thermal protection:

    • Check system for damage and repair if necessary.

    • Perform checks E and F.

  • For faults tripped by magnetic protection or caused by an unknown reason:

    • Check the system for damage, and then repair if necessary.

    • Perform checks A, E, and F.

Resetting the Circuit Breaker

Before resetting the circuit breaker, make sure that the fault is identified and repaired, and that the installation has been checked.

If the system must be restarted quickly (for example, in a safety installation), isolate and lock out the affected part of the installation before carrying out maintenance.

The procedure for resetting a circuit breaker depends on the type of handle on the circuit breaker (see Table of Contents for resetting each type of handle).

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