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Article 600: Electric Signs and Outline Lighting

Jun 1, 2008 12:00 PM, By Mike Holt, NEC Consultant

Location

Locate a sign (or outline lighting system) at least 14 feet above areas accessible to vehicles, unless you mechanically protect it from physical damage [600.9(A)] (Fig. 2 on page 62). Section 225.18(4) requires a minimum of 18 feet of overhead conductor clearance above public streets, alleys, roads, parking areas subject to truck traffic, and driveways on other than residential property. This may be an important consideration if you feed a sign with overhead conductors.

Protect neon tubing from physical damage, if you use it for signs, decorative elements, skeleton tubing, or art forms in locations that are readily accessible to pedestrians [600.9(B)]. Install signs and outline lighting systems in such a way that adjacent combustible materials aren't subjected to temperatures greater than 194°F. An incandescent or HID lamp/lampholder must have at least 2 inches of spacing from wood or other combustible materials [600.9(C)]. If you install signs or outline lighting systems in wet locations, ensure they are weatherproof and have drain holes [600.9(D)].

Portable or mobile signs

Portable or mobile signs must be adequately supported and readily movable without the use of tools [600.10]. Each portable or mobile sign must have an attachment plug. Remember that 400.8(2) and (5) prohibit flexible cords from being run through (or above) a suspended ceiling.

The cords for portable or mobile signs in wet or damp locations must be junior hard service or hard-service types with an EGC. In addition, the signs themselves must have factory-installed GFCI protection. If that's not the case with a particular sign, don't install it in a wet or damp location. The cords for portable or mobile signs in dry locations (as defined in Art. 100) must be SP-2, SPE-2, SPT-2, or heavier (see Table 400.4). These cords can't be longer than 15 feet [600.10(D)] (Fig. 3).

Ballasts, transformers, and electronic power supplies

Ballasts, transformers, and electronic power supplies must be accessible, securely fastened in place, and their secondary conductors must be as short as possible [600.21].

If ballasts, transformers, and electronic power supplies are installed outside of the sign (e.g., in a separate enclosure rather than in the sign), maintain a working space of at least 3 feet high by 3 feet wide by 3 feet deep [600.21(E)].

You can install ballasts, transformers, and/or electronic power supplies in attics and soffits, if the point of entry for each component has:

• An access door,

• A passageway not less than 3 feet high by 22½ inches wide, and

• A suitable permanent walkway at least 1 foot wide.

At least one lighting outlet that contains a switch (or is controlled by a wall switch) must be installed at the usual point of entry to these spaces. The lighting outlet must be at or near the equipment requiring servicing.

Ballasts, transformers, and electronic power supplies can be above a suspended ceiling, if the enclosures are securely fastened in place and don't use the suspended-ceiling grid for support [600.21(F)]. You cannot connect these to the branch-circuit wiring by a flexible cord (Fig. 4 on page 64). Once again, remember that 400.8(2) and (5) prohibit flexible cords from being run through, or above, a suspended ceiling.

Sidebar: Define the Sign

Article 100 defines an electric sign as any “fixed, stationary, or portable self-contained, electrically illuminated utilization equipment with words or symbols designed to convey information or attract attention.”

Outline lighting is an arrangement of incandescent lamps or electric-discharge lighting to outline (call attention to) certain features, such as the shape of a building or the decoration of a window.

Article 600 adds definitions in 600.2. Two important ones are:

1. Section sign

   A sign or outline lighting system, shipped as subassemblies that require field-installed wiring between the subassemblies to complete the overall sign. The subassemblies are either physically joined to form a single sign unit, or are installed as separate remote parts of an overall sign.

2. Skeleton tubing

   Neon tubing sign or outline lighting not attached to an enclosure.

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