Electrical signs and outdoor lighting are highly visible, safety-sensitive systems with unique code requirements for conductors, grounding and equipment access. They are the focus of Section 600 of the National Electrical Code.
Every commercial building needs a visual identifier, and most often, this comes in the form of an electrical sign. For this reason, NEC Section 600 is essential for anyone involved in industrial or commercial work.
What does NEC Section 600 cover?
Article 600 applies to the installation of conductors and equipment for:
Electrical signs (fixed, mobile or portable)
Lighting outline
Department Signs (Modular Signage Systems)
Skeleton tubes (neon or similar illumination not enclosed)
Retrofit kits to modify existing signs
It focuses on everything from wiring and security methods to safe mode and maintenance access. Even decorative or artistic neon tubes are included within this scope.
Equipment list and definitions
All electrical signage and detail lighting must be listed and rated to UL standards or equivalent. This includes:
Signature associations
Power supply
Retrofit kits
Neon tube components
Main definitions (600.2)
Electric sign: A self-contained, illuminated display using letters, symbols, or graphics.
Lighting outline: LEDs or discharge lighting used to trace architectural features.
Department tag: Modular signal system requires field installed wiring.
Skeleton tubes: Exposed neon tubes are not attached to a can.
Factory-assembled systems must be installed according to their lists. Exterior lighting and field-installed structural piping must comply with NEC Chapter 3 wiring methods.
Sub-circuit requirements
Custom circuit: Each tag should have its own 20A minimum A branch circuit with no other loads connected (600.5). This circuit can serve multiple outlets within a single load.
Signal ports: At least one sign outlet is required at each pedestrian accessible entrance to the tenant space.
Terminations: Sign wires must terminate in an enclosure, junction box or conduit body.
Pole-mounted signs: Columns may have connectors if they comply with 410.30(b).
All circuits shall be controlled by a disconnecting means that will open all ungrounded conductors.
Separation means
Each sign must have a clear sign, Externally operable disconnects Which:
He is Within sight of sign or controlled strip lighting (600.6)
He is Lockable in open position (There must be an integrated lock provided)
disconnect All connectors are grounded
If the signal is controlled by an external control unit (electronic or electromechanical):
Portable locks do that no Meet the requirements of the National Election Commission; Providing a lock must be part of the equipment.
Grounding and bonding
Signs and associated metal equipment must be grounded using Equipment Grounding Conductor (EGC) Per 250.118 and size according to 250.122.
Acceptable termination methods (250.8):
Optional auxiliary electrodes (600.7(a)(4)):
Not required, but allowed
He does no Need to meet 25 ohm or bonding requirements
It cannot serve as the primary path for the ground fault return
He remembers: Ground is not an effective current path for a ground fault.
Location and clearance
Vehicle clearance height: at least 14 feet The above areas are accessible to vehicles unless mechanically protected (600.9(a))
Overhead connectors: minimum 18 feet Clearance on public areas (per 225.18)
NEON IS PEDESTRIAN ACCESSIBLE: Must be physically protected (600.9(b))
Combustible materials: Keep at least Two inches From incandescent or HID bulbs (600.9(C))
Wet locations: Must be the signal Weatherproof And for her Drainage holes (600.9(d))
Portable and mobile banners
It must be Easily movable Without tools and properly supported (600.10)
Must use Attached components (Wires are not allowed)
Types of rope for Wet sites: Solid Service Starter (SJTW, SJEOW) with factory installed GFSI
Types of rope for Dry sites: SP-2, SPE-2, SPT-2 or heavier
Top Rope length: 15 feet
The ropes must be flexible no Run over or through suspended ceilings (per 400.8).
Ballasts, transformers, and power supplies
These components should be:
Accessible and securely fastened (600.21)
Installed with Minimum length of secondary conductor
Located in a sufficient container Workspace (Minimum 3ft x 3ft x 3ft if not in signature)
Installations in the attic or underground:
Must include: access door, 3′ x 22.5′ walkway, 1′ wide permanent walkway
You must have: a Lighting port It is controlled at the entrance and placed close to the equipment
Above suspended ceilings:
Wiring methods and cable types
NEC 600 requires wiring methods that protect connectors from mechanical impact (such as in public or vehicular-accessible areas), prevent water infiltration in wet location signs, and ensure routing stability in elevated or modular sign systems subject to wind, vibration, or thermal cycling.
Supported channels and groups:
EMT (Electrical Metal Tubing): Widely used for branch circuits in commercial buildings. Durable and easy to bend.
FMC (Flexible Metal Conduit): Good for short distances or where flexibility is required for shaking or planing.
LFMC (liquid flexible metal conduit): Use when exposure to moisture or oil is a factor.
MC cable (metal covered): This is a combination of both cable and conduit, making it suitable for internal signal branch circuits. It is commonly used in indoor signage installations and has connectors in the aluminum shield.
TC-ER cable (tray cable – exposed operation): Suitable for specific outdoor applications where exposed running is possible; The cable must be resistant to sunlight, oil and moisture.
Common connector types:
THHN/THHON-2: Heat and moisture resistant connectors used inside the conduit for both dry and wet locations. These are the wires that run through the EMT, FMC or LFMC channel.
UF cable (underground feeder): They can be used in pole-fed streamers or for direct burial where permitted, when streamers are fed from a raceway and underground trench.
Elastic cords: Use inside banners or portable signs. It must be listed for signage use and rated appropriately for temperature, flexibility and abrasion resistance. Depending on conditions, SJT, SJTW, SJEOW, and SOOW may be used.
Cable selection considerations:
Cables must be exposed to the elements UV resistant.
Connectors should be installed inside enclosures to avoid heat build-up and prevent contact with moving or hot parts.
All wiring outside factory-made signs must be used Included raceways or cable assemblies That are approved for a specific environment.
At Nassau National Cable, you’ll find cable types suitable for Article 600 installations, including:
Final thoughts
NEC Section 600 provides a comprehensive framework for the installation of electrical signs and detail lighting. When installing or maintaining signage systems:
is used Included equipment and retrofit kits
He extends Dedicated subcircuits And the right one Means of disconnection
Follow the rules for Grounding, Connector routingand GFCI protection
He chooses Approved wiring methodsChannel systems and cable types
Ensure all parts are easily accessible and meet NEC 600 spatial and mechanical protection rules.
