- Corrective: This is commonly referred to as "run to failure" maintenance. These actions can be either planned or unplanned. Planned corrective actions could entail things like replacing a light bulb or a fuse when it fails. It would be foolish in most instances to assign any of the other types of maintenance to these types of devices. Unplanned corrective action on the other hand would entail repairing a device when it malfunctions or fails because we failed to apply a more positive form of maintenance to it. We're all familiar with these unplanned interruptions. A call out in the middle of the night to fix a circuit breaker air system because we received a low pressure alarm is just one such instance of this.
Preventive: This maintenance category is defined as time or event triggered maintenance. Performing monthly substation inspections, performing battery capacity testing every 5 years, and performing circuit breaker overhauls after "X" number of years or "Y" number of fault operations are examples of this mode of maintenance. This maintenance can be both comforting and disturbing. We know that every piece of equipment on this maintenance schedule will be looked at eventually. However, relying strictly on an event trigger may not always work. We may over maintain some equipment and under maintain others. Many LTCs have been opened up only to find them in perfectly good condition. Conversely, we've seen LTCs fail before they came up on our maintenance schedule.
