Lockout/tagout devices

Lockout/tagout devices are the locks, tags and clamping hardware used to hold power sources off and isolated, so that no one is exposed to hazardous energy while equipment is serviced. A lockout device has a keyed or combination lock and a way to show who installed it. The person who installed the lock, or the person in charge, keeps the key or combination. A tag attached with a lock must say that no one may operate the disconnect or remove the device without authorization. Tag attachments must be non-reusable and self-locking, comparable to a nylon cable tie. Locks and tags used against electrical hazards must be unique, easy to recognize as lockout/tagout devices, and used for nothing else. They go only on circuit disconnecting means, never on control devices such as pushbuttons or selector switches. On PV systems, AC and DC disconnect switches and disconnecting combiners have handle holes or tabs that take a padlock. Single breakers can be locked off with clamp-type breaker lockouts, or you can lock the whole panel lid. Do not unplug array connectors until the load-break rated disconnect is open and a DC clamp meter shows no current, because a fault can leave current circulating in the array. After locking and tagging, release any stored energy, try to operate the disconnect, then test for absence of voltage with a test instrument. Check the instrument on a known voltage source before and after the test. Lockout/tagout is covered by 29 CFR 1910.147 and NFPA 70E. The employer must supply the devices and train workers to use them.

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• sentence 8: support check: partial - 29 CFR 1910.147 coverage, employer-provided equipment, and training are stated, but the passages mention NFPA 70E only loosely (article 120 is not named as NFPA 70E explicitly aside from the transcript's mention), and training of workers to use devices is stated only as lockout/tagout training. -->