National Electrical Installation Standards

Standards as High as Your Own

Monday, September 11, 2023


Hi CQD, I am Commissioning a DoD project where there is a lockable electrical breaker panel located within site of the chillers, pumps, water heater, etc. The designer has not included any other individual disconnect for the individual pump, chiller, heater. Are the breakers in the lockable panel acceptable as a lock-out device or does each individual chiller, pump, water heater require an individual disconnect? Thanks in advance, Glyn Humphrey


Hi Glyn, a circuit breaker OCPD may be permitted as the disconnecting means for the installations described in the question. Whether or not these disconnects are required to be lockable in the open condition will depend on a number of variables. However, if these disconnects are required to be lockable in the open position the locking door on the panel cover would not be compliant, as the OCPD must be locked in the open position, and this is not accomplished by locking the panel access door. Take a look at the following Code Sections for more information on specific equipment:

  • General Lockable Disconnect Requirement – 110.25
  • Appliance Disconnecting Means - 422.31
  • Motor Disconnecting Means – 430.109 & 430.110
Refrigeration Equipment Disconnecting Means - 440.12 & 440.13

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