Wire Raceway / Molding Symbol
Definition: The Wire Raceway / Molding symbol represents a surface-mounted cable management channel used in wiring diagrams to denote a flat-profile plastic or metal enclosure that routes and protects electrical conductors along walls, floors, or ceilings where concealed conduit installation is impractical, in compliance with NEC Article 386/388 and IEC 61084.
Also known as: surface raceway, wiremold, cable molding, surface wiring duct, baseboard raceway, cable raceway, surface conduit.
What the Wire Raceway / Molding symbol means
The Wire Raceway / Molding symbol identifies the surface-mounted cable routing channel at a specific location in a wiring diagram. It indicates that conductors between two points are routed inside a snap-on or screw-on plastic or metal track that is visible on the surface of walls, floors, or ceilings rather than concealed inside conduit or within the structure.
The symbol's two terminals—Left and Right—represent the entry and exit points of the raceway run. In renovation and retrofit wiring diagrams the raceway symbol alerts the installer that special surface-mount fittings (elbows, T-joints, end caps, outlet boxes) are required to complete the installation, and that the conductor fill must comply with the raceway manufacturer's listing and NEC fill tables.
How to identify the Wire Raceway / Molding symbol
The symbol is drawn as a narrow, flat rectangle (wider than it is tall, representing the channel cross-section) with horizontal lines indicating the surface-mounted profile. Left and Right terminals are at the two ends. In plan-view diagrams the raceway may be drawn as a bold or double line along a wall, distinguished from conduit by its flat rectangular cross-section label.
Function in a circuit
A surface raceway provides mechanical protection, electrical isolation, and organised routing for conductors installed on building surfaces without the need to cut channels into walls or pull wires through concealed spaces. The snap-off cover provides access for future conductor additions or changes. Raceways are commonly used in office fit-outs for power and data cables, in retrofit commercial installations, and in accessible wiring for industrial bench applications.
Standards: IEC vs ANSI
| IEC 60617 | IEC 61084-1 (cable trunking and ducting systems) and IEC 61084-2-2 (surface mounted cable trunking systems) cover the dimensional, mechanical, fire, and electrical requirements for surface-mounted raceways. IP-rated covers (IP2X minimum for finished wall surfaces) are specified in IEC 60529. |
|---|---|
| ANSI/IEEE 315 | NEC Article 386 (metal surface raceways) and Article 388 (non-metallic surface raceways) govern surface raceway installations in the United States. UL 5 (surface metal raceways) and UL 5A (non-metallic surface raceways) are the listing standards. The raceway fill is limited to the number and size of conductors listed on the raceway or in NEC Table 386.22 / 388.22. |
| Key difference | IEC 61084 uses dimensional type codes and IP ratings; NEC Articles 386/388 use ampacity fill tables. IEC allows both power and data cables in the same raceway if separated by a divider; NEC Article 386.10(5) requires conductors of different voltage levels to be separated by a barrier within the raceway. |
Terminals / pins
| Pin | Name |
|---|---|
| left | Left |
| right | Right |
Typical values
Common cross-sections: 8×13 mm (1-gang), 16×28 mm (2-gang), 25×40 mm (3-gang); conductor fill: per manufacturer's listing table or NEC Table 386.22/388.22; material: PVC or steel; colour: white, ivory, or paintable; maximum voltage: 300 V (2-wire) or 600 V (larger multi-conductor sizes); typical length per section: 2.4 m (8 ft).
Where the Wire Raceway / Molding symbol is used
- Office renovations adding power and data outlets to perimeter walls without opening wall cavities
- Retail displays and exhibition stand wiring where surface-mounted cabling must be neat and accessible
- Industrial bench and workstation wiring providing tool outlets along work surfaces
- Accessible wiring installations in older buildings where structural constraints prevent conduit runs
- Temporary partition walls and modular office systems routing power and data to desk clusters
- Residential garage and workshop bench wiring where plastic surface raceway replaces exposed conduit
Example
In an office fit-out wiring diagram, the wire-raceway symbol runs along the baseboard of three perimeter walls, with junction boxes at each corner; the raceway carries two 20 A, 120 V branch-circuit conductors and a data cable, separated by an internal divider, feeding duplex outlet and RJ45 jack symbols spaced 1.8 m apart along the raceway run.
Key facts
- The Wire Raceway / Molding symbol has two terminals: Left and Right, representing the entry and exit ends of the surface-mounted cable channel run.
- NEC Article 386 (metal) and 388 (non-metallic) govern surface raceways; fill limits are specified in NEC Tables 386.22 and 388.22 based on conductor size and insulation type.
- Conductors of different voltage systems (e.g., 120 V power and 24 V control) must be separated by a barrier within the same raceway per NEC 386.10(5).
- Surface raceways are limited to installations in dry locations; they are not permitted in damp or wet locations unless specifically listed for such use (NEC 386.10).
- IEC 61084-2-2 classifies surface raceways by dimensional type codes and requires a minimum IP2X protection level (finger-proof) for covers used in accessible areas.
- Metal surface raceways (Wiremold brand is a common example) can be used as the equipment grounding conductor path if listed for that purpose, eliminating the need for a separate ground wire inside the raceway.
- Common surface raceway cross-sections range from 8×13 mm (single-gang, 2 conductors) to 100×50 mm (high-capacity, 8+ conductors) with matching corner fittings, T-junctions, and device boxes.
Frequently asked questions
What does the wire raceway symbol mean in a wiring diagram?
The wire raceway (molding) symbol represents a surface-mounted cable management channel that routes and protects conductors along walls, ceilings, or floors. It indicates that wiring between the two endpoints is installed in a visible snap-on plastic or metal track rather than inside a wall or in conduit.
What does a wire raceway look like in a wiring diagram?
The symbol appears as a narrow, flat rectangle (wider than tall) with Left and Right terminals at each end, representing the surface-mounted channel profile. In plan-view diagrams it may appear as a bold or double line running along a wall, annotated with the raceway size or type.
What NEC article governs surface raceways?
NEC Article 386 governs metal surface raceways and Article 388 governs non-metallic surface raceways. Both articles specify permitted uses, installation rules, and conductor fill limits. UL 5 and UL 5A are the corresponding listing standards for metal and non-metallic surface raceways respectively.
What is the IEC vs ANSI difference for surface raceway standards?
IEC 61084-2-2 covers surface-mounted cable trunking systems with dimensional type codes and IP-protection ratings. NEC Articles 386/388 specify conductor fill tables and installation requirements. Both cover functionally identical products; IEC focuses on dimensional and protection classes while NEC focuses on fill capacity and permitted applications.
Can power and data cables share the same surface raceway?
Yes, if the raceway has an internal divider separating power conductors from data cables. NEC 386.10(5) requires that conductors of different voltage systems be separated by a barrier inside the same raceway. IEC 61084 similarly allows mixed wiring with a divider partition.
How many terminals does the wire raceway symbol have?
The wire raceway symbol has two terminals: Left and Right, representing the two ends of the raceway run. Conductors enter and exit through these ends (and through outlet or device boxes fitted along the raceway), but the symbol marks the overall routing path rather than individual conductor connections.
Can a metal surface raceway serve as the equipment ground?
Yes, if the metal surface raceway is listed for use as an equipment grounding conductor and all fittings (elbows, T-joints, couplings) are listed to maintain continuity. This eliminates the need for a separate green or bare ground wire inside the raceway, but the listing must be verified before relying on the raceway as the sole equipment ground path.
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