CSLB C-10 Electrical ContractorEquipment and InstallationMedium
A contractor installs new fluorescent luminaires with ballasts in a commercial warehouse. The ballasts are designed to be serviced in place. Per NEC 410.130(G), what is required for these luminaires?
- AA disconnecting means is required only for luminaires installed above 10 feet.
- BA disconnecting means is only required if the luminaire is located outdoors.
- CNo disconnecting means is required because the branch-circuit breaker in the panelboard serves this purpose.
- DA disconnecting means must open all ungrounded conductors of each ballast within the luminaire or group of luminaires on the same circuit.
Show answer & explanationAnswer & explanation
Correct answer: D. A disconnecting means must open all ungrounded conductors of each ballast within the luminaire or group of luminaires on the same circuit.
NEC 410.130(G) requires that fluorescent luminaires with double-ended lamps and ballast(s) that can be serviced in place, in indoor locations other than dwellings, be provided with a disconnecting means that opens all ungrounded conductors supplying the ballast(s), to protect service personnel.
Why the other options are wrong
- A. Mounting height is not the determining factor for this requirement.
- B. The rule applies to indoor non-dwelling locations, not specifically outdoor fixtures.
- C. The remote panelboard breaker does not satisfy the local disconnect requirement at the fixture.
Luminaire Ballast Disconnect (410.130(G))
Indoor fluorescent luminaires (other than dwellings) with ballasts serviceable in place require a disconnecting means to open all ungrounded conductors before servicing.
- Protects maintenance personnel from live ballast circuits
- Applies to indoor, non-dwelling occupancies
- Disconnect can serve a single luminaire or a group on the same circuit
Memory trick: 'Before you touch the ballast, cut the juice first.'