When do you need to use the lockout/tagout system?

Lockout and tagout system is required to be used under the following conditions.

a. When an energized piece of equipment needs to be serviced or requires some maintenance.

b. Under normal operating circumstances when you need to remove or bypass a safety guard.

c. Placing a body part (extending your hand, for example) into an operational zone that is hazardous during normal operation.

Notice from the above that you need to use the lockout/tagout system when you do something non-routine which happens to be hazardous.