Critical operations, fast-paced e-commerce fulfillment, and just-in-time manufacturing requires a building’s electrical system to operate continuously without interruption. However, proper preventive maintenance of the building's electrical system and electrical apparatus is often overlooked by the facility owner and operations team. Many times, poor preventive maintenance is to blame for equipment damage and misoperations. In reality, power quality anomalies are often identified as the root cause of operational downtime and product loss.
It is up to each company to develop the proper preventive maintenance program that is customized to their facilities' needs and operation. The criticality of equipment to the operation will increase the frequency of maintenance activities. Guidance can be found from ANSI/NETA Standard for Maintenance Testing Specifications for Electrical Power Equipment and Systems. Appendix B – Frequency of Maintenance Tests provides a quick reference table by electrical equipment type. The maintenance frequency is ranked by equipment condition and the equipment reliability requirement. Three types of maintenance procedures are laid out: visual, visual/mechanical, and visual/mechanical/electrical. Switchgear with a medium reliability rating and average condition should be visual/mechanical inspected every 12 months and visual/mechanical/electrical every 24 months. Ground-fault protection systems are frequently forgotten and left untested for decades. However, these systems are recommended to be visually inspected every 2 months, visual/mechanical every 12 months, and visual/mechanical/electrical every 24 months.
An example of neglected preventive maintenance was found at a company that makes steel screws. The manufacturer was experiencing damage on multiple adjustable speed drives (ASDs). The drives were failing prematurely. They were installed inside an electrical equipment room and located in closed cabinets. As soon as the cabinets were opened to inspect, it became clear there was no preventive maintenance plan being followed.
On top of all the ASDs, controls, communication systems, and circuit breakers was a layer of metallic dust. The metallic dust generated by the manufacturing of the screws was being drawn into the electrical room and cabinets through the ventilation system. The failures occurred when the metallic dust settled in the power electronics of the ASDs.
Equipment damage is not always caused by electrical system events, such as power quality anomalies. Proper preventive maintenance plans need to be created and enforced to ensure operations continue with minimal interruptions.
