In a multi-source system feeding a bus from multiple sources, equipment containing which type of devices in circuits shall be marked to indicate the presence of all sources?

In a multi-source system feeding a bus from multiple sources, equipment containing which type of devices in circuits shall be marked to indicate the presence of all sources?

• A. Electric devices
• B. Overcurrent devices
• C. Switching devices
• D. Wiring

Answer: (B)

When multiple sources can energize the same bus, it’s essential to clearly signal that more than one source may be present. The equipment that needs this marking is the one containing the devices that actually connect and disconnect power from those sources—the overcurrent protection devices (fuses or circuit breakers). Marking these locations warns technicians that the bus can be energized from more than one source and that de-energizing one device may not remove all power, guiding proper lockout/tagout and safe servicing. Other items like general electric devices, switching devices, or wiring by themselves don’t specify how many sources can energize the bus or who controls the power paths, so they aren’t the correct targets for this particular marking requirement.

When multiple sources can energize the same bus, it’s essential to clearly signal that more than one source may be present. The equipment that needs this marking is the one containing the devices that actually connect and disconnect power from those sources—the overcurrent protection devices (fuses or circuit breakers). Marking these locations warns technicians that the bus can be energized from more than one source and that de-energizing one device may not remove all power, guiding proper lockout/tagout and safe servicing.

Other items like general electric devices, switching devices, or wiring by themselves don’t specify how many sources can energize the bus or who controls the power paths, so they aren’t the correct targets for this particular marking requirement.