All references are based on the 2017 edition of the NEC, unless otherwise noted.
The type of “breaker lock” installed on this circuit breaker is a popular way to secure the breaker in the ON position so it does not get inadvertently switched off. Quite often, I see this type of device installed on circuit breakers for fire alarm systems. Unfortunately, this type of “breaker lock” is no longer permitted due to recent changes to the definition of “readily accessible” in Art. 100.
For this circuit breaker to be considered readily accessible, as required by Sec. 240.24(A), it must be capable of being reached quickly for operation, renewal, or inspection without requiring those people who need access to climb over or under, remove obstacles, use portable ladders, or resort to the use of tools other than keys. Since this lock requires the use of a Philips screwdriver to remove it, the circuit breaker does not meet the definition of “readily accessible.” Ironically, if this “breaker lock” or the panel cover were capable of being locked or unlocked with the use of a key, the circuit breaker would be considered “readily accessible.”
There are many other types of breaker lock devices available on the market that can be installed and still allow this circuit breaker to be considered “readily accessible.” Compliant lockout devices include: those with thumb screws for securing or removing the locking device from the breaker; those that could be installed or removed by hand without the use of tools; and those that may require a key to install or remove them. Using a screwdriver to remove this breaker lock may not take any longer than using a key to remove a lock, but it is literally a violation if a screwdriver is needed. I suppose if you could convince the AHJ that you could remove this device with a key instead of a screwdriver — or simply by using your hand — he or she might go along with your idea.
While the Code may not specifically prohibit the practice of securing a switch or circuit breaker in the ON position, it does not specifically permit this practice either, other than in Sec. 760.41(A) for fire alarm circuits and Secs. 700.12(F)(2)(3) and 701.12(G) for unit equipment lighting packs. Certain industrial processes, hazardous gas ventilation systems, medical equipment, and other life safety equipment could create a safety hazard if the circuit was inadvertently shut off, just as it would in the case of a fire alarm system.
