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Illustrated Changes to the NEC, 2005 Edition - Part 2

Article 410

Luminaires (Lighting Fixtures), Lampholders, and Lamps

410.73 General

New rule to require disconnecting means for fluorescent luminaires that have double-ended lamps and contain ballast(s), but this doesnít become effective until January 1, 2008.

(G) Disconnecting Means. In indoor locations, other than dwellings and associated accessory structures, fluorescent luminaires that utilize double-ended lamps and contain ballast(s) that can be serviced in place or re-ballasted must have a disconnecting means, to disconnect simultaneously all conductors of the ballast, including the grounded (neutral) conductor if any. The disconnecting means must be accessible to qualified persons. This requirement will become effective January 1, 2008 (Basically a 2008 NEC requirement).

Authorís Comment: Changing the ballast out while the circuit feeding the luminaire is energized has become a regular practice, because a local disconnect isnít available. Also, ballasts are often serviced from a ladder, adding the possibility of increased injury from a fall. The rule requires the disconnecting means to open ďall circuit conductors,Ē including the grounded (neutral) conductor. If the grounded (neutral) conductor in a multiwire circuit isnít disconnected at the same time as the ungrounded conductor, a false sense of security could result in an unexpected shock, and its consequences, from the grounded (neutral) conductor.

Ex 1: A disconnecting means isnít required for luminaires installed in hazardous (classified) location(s).

Ex 2: A disconnecting means isnít required for emergency illumination required in 700.16.

Ex 3: For cord-and-plug connected luminaires, an accessible separable connector or an accessible plug and receptacle is permitted to serve as the disconnecting means.

Ex 4 A disconnecting means isnít required in industrial establishments with restricted public access where written procedures and conditions of maintenance and supervision ensure that only qualified persons service the installation.

Ex 5 Where more than one luminaire is installed and supplied by other than a multiwire branch circuit, a disconnecting means isnít required for every luminaire when the design of the installation includes locally accessible disconnects, such that the illuminated space wonít be left in total darkness


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