How rating of main switch and cable is selected for Industrial Installation.

How rating of main switch and cable is selected for Industrial Installation.
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1 Answer

Answer :

1. Rating of Main Switch or Fuse Rating is decided in industrial installation: Rating of main switch or fuse is based up the starting current of motor. For calculating starting current is considered 2 times that of full load current,. Thus main switch is decided. If number of motors are there, then main switch is decided from following formula.

Incoming current = Starting current of highest rated m/c + Full load current remaining all m/c Thus from incoming current main switch is decided


2. Cable Rating is decided considering following points in industrial installation: The current rating of cables for supply to motor is based up on the normal full load current of motor considering the overload capacity 50% We take 1.5 times the rated current or full load current. & thus cable rating is decided.

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