Protective device coordination means that downstream devices (breakers/fuses) should activate before upstream devices. This minimizes the portion of the system effected by a fault or other disturbance. At the substation level, feeder breakers should trip before the main. Likewise, downstream panel breakers should trip before the substation feeder supplying the panel. 

If you've experienced nuisance tripping or have adjustable trip breakers/relays without documentation supporting the existing settings, a coordination study is a great investment. If your facility uses adjustable trip circuit breakers and/or relays, do you know what the existing device settings are and why? In far too many cases, no one knows what the settings are, where they came from, or whether they make any sense at all.

Don't wait for an outage to find out there's a problem.

This study examines the size and settings of protective devices in system. National Electric Code requirements and ANSI/IEEE standards are considered to determine if existing devices are adequately applied. Recommended sizes and/or settings are provided in a written report aimed towards improving system protection and coordination.