Low Voltage Circuit Breaker Testing

[nhee2]

What is the typical test frequency that others see or implement for testing of LV 480 VAC molded case breakers? In this case - 400 - 1200 A breakers with electronic trips, installed in facility switchboard. NFPA 70B (2016) recommends electrical testing every 3-5 years. What percentage of facilities do you see maintaining this schedule? Is secondary injection testing at those time intervals typical?

Thanks for any input

 

[mayanees]

My experience is that I could get by at my facility with bi-annual maintenance, that's every other year. This was a paper and finished products manufacturing facility.
NETA MTS standard shows in Appendix B of the 2015 edition the development of a Factor for Frequency of Maintenance Tests which looks at the reliability requirement of the application and the condition of the equipment. A number is developed which is then multiplied by the Inspections and Frequency of test requirement for all the different electrical of devices and an interval is developed for testing.
I specified line injection testing for breakers that were Acceptance tested (first time), and secondary injection for the Maintenance testing with a continuity test for the CT.

 

[DrSparks]

I would think testing frequency would also depend on the environment. I worked in a die cast facility and we swapped breakers out annually and sent them out for testing at a lab.

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