Understanding NEC Article 600: Electric Signs and Outline Lighting
NEC Article 600 provides safety standards for the installation and operation of electric signs, outline lighting, and associated components. This includes fixed, portable, and mobile systems, regardless of the voltage used. From neon tubing to LED systems, the article ensures these systems operate safely and efficiently.
Scope of Article 600
This article applies to:
- Electric signs, retrofit kits, and outline lighting.
- Neon tubing for artistic, decorative, or functional applications.
Included Illumination Systems:
- Cold cathode neon tubing.
- High-intensity discharge (HID) lamps.
- Fluorescent, incandescent, LED, electroluminescent, and inductance lighting.
Key Requirements for Electric Signs
- Listing and Labeling
- All electric signs and outline lighting systems must be listed and labeled for their intended use.
- Manufacturers must provide installation instructions, and signs must conform to their listings.
- Markings
- Markings must display input voltage, current rating, and manufacturer details.
- Retrofitted signs must be labeled to indicate modifications and warn against the use of incompatible components (e.g., fluorescent lamps in LED-retrofitted signs).
- Branch Circuits
- A dedicated 20-amp circuit must supply electric signs in commercial buildings, with no other load sharing the circuit.
- Circuits are treated as continuous loads and sized accordingly.
- Disconnecting Means
- A disconnect must be provided for each sign or lighting system to allow local control during maintenance.
- Disconnects must be lockable in the open position if not within sight of the sign.
- Wiring Methods
- Conductors must terminate in approved enclosures or junction boxes.
- Enclosures can act as pull boxes for branch and secondary circuits.
Grounding and Bonding
- All metal parts of signs and lighting systems must be bonded together and to the equipment grounding conductor.
- Auxiliary grounding electrodes may be used but are not substitutes for equipment grounding.
- Flexible conduits can serve as bonding means if lengths do not exceed 100 feet.
Portable and Mobile Signs
- Must include attachment plugs and support systems for ease of movement.
- Signs for wet locations require weatherproofing and GFCI protection for cords.
Applications
Article 600 applies to:
- Commercial Signs: Indoor and outdoor signs for advertising and branding.
- Artistic Neon Installations: Neon tubing used for decorative purposes.
- Specialty Signs: LED or electroluminescent systems in architectural designs.
Conclusion
NEC Article 600 ensures the safety and functionality of electric signs and outline lighting by addressing requirements for listing, wiring, grounding, and labeling. By adhering to these standards, professionals can ensure installations are compliant and minimize risks associated with high-voltage systems.
