OSHA’s electrical safety standards at 29 CFR 1910.333 generally require employers to de-energize and lockout electrical supply to a circuit before work can be performed nearby. 

However, the OSHA standard includes an exception to de-energization if doing so is “infeasible due to equipment design or operational limitations” or if de-energizing introduces additional or increased hazards.

Data center operators have long relied on this exception to perform work inside live electrical panels, because shutting down the entire panel will take down all equipment powered from that source, often including critical hardware hosting critical business operations. It needs to be clear, however, that the infeasibility exemption was never intended to cover situations of financial impact or inconvenience. 

Some data centers have attempted to make an argument from the perspective of interrupting “continuous industrial process.” In one of its letters of interpretation, however, OSHA clarified that the term “continuous industrial process” was derived from its use in the National Electrical Code (NEC).

In the NEC “continuous industrial process” is used in the context of situations where the orderly shut down of integrated processes and equipment would introduce additional or increased hazards. Therefore, to qualify for the exception found in Note 2 of §1910.333(a)(1), the employer must, on a case-by-case basis, determine if the orderly shutdown of the related equipment (including the panel) and processes would introduce additional or increased hazards. If so, then the employer may perform the work using the electrical safe work practices found in §§1910.331-1910.335, including, but not limited to, insulated tools, shields, barrier, and personal protective equipment. If the orderly shutdown of the related equipment and processes would not introduce additional or increased hazards, but merely alter or interrupt production, then the de-energization of the equipment would be considered feasible, and the exception found in Note 2 of §1910.333(a)(1) would not apply.