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Precautions for the installation and use of low-voltage circuit breakers

By:Nader Updated:September 09,2020 11:31AM

(1) The upper terminal of the circuit breaker is the incoming terminal, and the lower terminal is the outgoing terminal. The "N" is extremely neutral, and it is not allowed to flip.

(2) When the low-voltage circuit breaker is used as the main switch or the control switch of the motor, an isolating switch, knife switch or fuse must be installed on the power inlet side of the circuit breaker as an obvious disconnection point. All products with grounding screws should be grounded reliably.

(3) After the circuit breaker is overloaded or short-circuit protected, the fault should be eliminated first, and then the closing operation should be performed.

(4) The current carried by the circuit breaker is too large, the handle is already in the trip position and the contacts of the circuit breaker are not completely disconnected. At this time, the load end is in abnormal operation, and the current needs to be manually cut off and the circuit breaker is replaced.

(5) After the circuit breaker disconnects the short-circuit current, open the circuit breaker to check the contacts and operating mechanism. If the contacts are intact, the operating mechanism is flexible, and the test button is reliable in operation, it is allowed to continue to use. If there are traces of arc smoke, wipe it off with a dry cloth. If the arc contact has been singed, it can be carefully trimmed with a fine file, but when the singeing is severe, the circuit breaker should be replaced to avoid accidents.

(6) After long-term use, the burrs and metal particles on the contact surface can be removed to maintain good electrical contact.

(7) The circuit breaker should be inspected and maintained periodically, and the power supply should be cut off during inspection. Periodic inspection items include:

  • Add lubricating oil to the transmission part:
  • Remove the dust on the surface of the shell and maintain good insulation;
  • Remove the metal particles and black soot on the walls and grids of the arc extinguishing chamber to maintain a good arc extinguishing effect. If the arc extinguishing chamber is damaged, the circuit breaker cannot be used.