What must be installed in fluorescent luminaires using double-ended lamps during ballast replacement?

In fluorescent luminaires that utilize double-ended lamps, it is essential to install a disconnecting means during ballast replacement. This requirement is in place to ensure safety and facilitate maintenance. A disconnecting means allows for the complete isolation of the electrical supply to the luminaire, thereby preventing accidental electrical shock to workers who may be replacing the ballast or the lamps.

The presence of a disconnecting means ensures that power can be safely turned off and that there is no risk of live electrical connections while performing maintenance tasks. This is particularly important in fixtures that may require someone to physically interact with the electrical components, as it safeguards personnel from hazards associated with electrical maintenance.

Other options, while potentially useful in various contexts, do not address the specific safety requirements outlined in the National Electrical Code (NEC) for this application.