LGE-2 — Electric Signs and Outline Lighting

Exam checkpoints

Start with Article 600, then keep the general rules

Article 600 covers the installation of conductors and equipment for electric signs and outline lighting. A cabinet sign, channel letters, border tubing, an LED message center, and field-installed neon skeleton tubing may look like lighting equipment, but Article 600 is the starting point. Chapters 1 through 4 still govern such matters as conductor ampacity, wiring methods, boxes, environmental ratings, working space, overcurrent protection, and grounding unless Article 600 modifies them.

Section 600.3 requires electric signs and outline-lighting systems to be listed unless a stated rule covers the field-installed arrangement. Section 600.4 requires identification such as the manufacturer or installer and the electrical input rating. Read the complete nameplate: input voltage and current, frequency where applicable, wet-location marking, lamp or power-supply limitations, and any secondary-circuit information. A listed sign is evaluated as an assembly. Replacing its power supply, drilling new raceway entries, or adding field conductors does not permit the installer to defeat the listing instructions.

A sign installed outdoors is ordinarily in a wet location, even when it has a decorative top. Use equipment and fittings identified for that environment, arrange entries and drain or weep provisions as instructed, and prevent water from accumulating in wiring compartments. Close unused openings with listed closures and maintain access to components intended for service. The enclosure is not a general-purpose junction box for unrelated tenant loads.

Separate the required outlet from the installed sign load

Section 600.5(A) requires each commercial building and each commercial occupancy accessible to pedestrians to have at least one accessible outlet at each entrance to each tenant space for sign or outline-lighting use. That outlet is supplied by a branch circuit rated not less than 20 A and the circuit supplies no other load. Service hallways and service corridors not considered pedestrian entrances do not create the same requirement. The outlet is required even when the tenant has not yet selected a sign.

Do not reverse the wording. The required outlet circuit has a minimum rating of 20 A; that does not mean every sign may be placed on an arbitrarily large breaker. Section 600.5(B) limits ordinary sign and outline-lighting branch circuits to 20 A and permits up to 30 A for neon tubing installations, subject to its details and any stated provision for a larger sign. Apply the actual equipment nameplate, conductor ampacity, and overcurrent rules. Sign and outline-lighting loads are treated as continuous loads when sizing the branch circuit.

For service or feeder load calculations, 220.14(F) assigns at least 1,200 VA to each branch circuit required by 600.5(A), not 1,200 VA to every individual sign outlet placed on that same required circuit. Two required sign branch circuits contribute at least 2 × 1,200 = 2,400 VA before adding any larger known load that the calculation must recognize.

Provide a real disconnect

Under 600.6, each sign or outline-lighting system and the feeder or branch circuit supplying it is controlled by an externally operable switch or circuit breaker that opens all ungrounded conductors and controls no other load. The disconnect must be accessible and located within sight of the sign or outline-lighting system, or be capable of being locked in the open position where the 2017 rule permits it to be out of sight. A disconnect for a multiwire supply opens all ungrounded conductors as required; opening only one pole can leave part of a sign energized.

A time clock, photocell, contactor, dimmer, remote keypad, or software command may operate a sign without isolating its supply. Treat controller and disconnect as different functions unless the installed device is listed, rated, and arranged to perform both. A disconnect hidden behind a sign face is not externally operable merely because a technician can remove screws. Where a controller is remote, apply the controller-location provisions and ensure service personnel can identify and secure the disconnect.

Switches, flashers, and similar devices controlling transformers or electronic power supplies must be suitable for the inductive load or have the current rating specified by 600.6(B). An ordinary ampere rating does not automatically establish suitability for transformer inrush. Mark the controlled sign clearly where several tenant circuits or sign sections could be confused.

Bond the enclosure and protect field wiring

Section 600.7 requires grounding and bonding of metal sign parts and metal outline-lighting equipment, apart from equipment that qualifies for a stated exception such as listed double-insulated equipment. Run an equipment grounding conductor with the supply as required, bond cabinet sections, raceways, transformer or power-supply enclosures, and accessible metal that could become energized. The grounded circuit conductor is not the equipment grounding conductor, and mounting a cabinet on masonry is not a fault-current path.

Field-installed supply conductors use the applicable Chapter 3 wiring method and enter through fittings identified for the enclosure and location. Protect conductors from sharp sheet-metal edges, maintain bending space and conductor temperature ratings, place splices in approved accessible compartments, and keep primary and secondary wiring separated as the listing and Article 600 require. Do not run unrelated branch-circuit conductors through a sign simply because the cabinet is hollow.

LED modules supplied by a listed Class 2 power source remain subject to the power-source listing, output limitations, wiring method, support, polarity, and separation instructions. Class 2 status does not waive physical protection or permission for the space. A field alteration that is outside the evaluated instructions may require a field evaluation or a listed retrofit system rather than an improvised splice.

Recognize the neon secondary hazard

Field-installed skeleton tubing and neon secondary circuits can operate at thousands of volts. Use transformers or electronic power supplies, electrodes, receptacles, bushings, and secondary cable listed for sign use. Keep the high-voltage secondary separate from primary and unrelated wiring, protect it from physical damage, and make electrode connections within suitable housings. Required secondary-circuit ground-fault protection is part of the system; it is not a substitute for cabinet bonding.

Section 600.32 limits secondary-conductor length to control capacitive current and performance. For a solid copper secondary conductor between a transformer or power supply and the first neon tube, the general maximum is 20 ft; other conductor constructions and installation conditions can have different limits. Locate and arrange the power supply according to Article 600 and its listing instead of extending secondary wiring for convenience. Before energizing, verify the branch rating, disconnect operation, bond continuity, enclosure closure, wet-location details, secondary routing, and all field-applied markings.