In August 2002, mill maintenance surveyed nearly 400
breakers and removed three MCCBs from service in the
Paper Machine No. 3 and Deink area of the mill. The No. 3
Fig. 6: Paper mill Thermographer conducting thermal scan survey
of low-voltage MCC compartment.
machine was originally commissioned in 1990 as opposed to
the other two paper machines, No. 1 and No. 2 that were
commissioned in 1978 and 1980 respectively. Because the
older section of the mill was built in an era when circuit
breaker interrupting ratings were typically much lower, the No.
1 and No. 2 machine areas included thermal-magnetic circuit
breakers with integral current-limiters for each motor circuit.
The current-limiters were required due to the mill system
available fault current exceeding the vintage MCCBs
capability as a stand-alone overcurrent protective device. The