Policy:
1. General Requirements
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All wiring inside control panels must be color-coded in accordance with this policy if they are single wires. For cables with multiple wires within, various colors are used for wire tracing and identification. Therefore this color policy does not apply to multi lead cables.
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Deviations from this policy must be approved in writing by the Management.
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All conductors shall be marked or color-coded throughout their length or clearly identified at terminations.
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All wire insulation must be rated appropriately for the voltage and environment in which it is used.
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Many of the current panels were not built with this standard. Although all future panels will be, do not assume voltage based on color. Make sure to verify.
2. Wire Color Coding Table
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Function / Voltage Level
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Color
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Notes
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24 VDC – Positive (Hot)
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Blue
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Used for control signals and low-voltage DC power. Red wire of 18 gauge or smaller could be used in absence of blue.
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24 VDC – Negative (Return)
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Blue with White Stripe
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Alternately white with blue stripe if using white wire stock. Solid blue can be used in absence of striped wire.
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120 VAC – Line (Hot)
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Black
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Any gauge is approved depending on use
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120 VAC – Neutral
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White
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Any gauge is approved depending on use
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208 VAC – Line (Hot)
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Black, Red
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Red must be 16 gauge or larger to not be confused with 24VDC.
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208 VAC – 3 Phase
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Black, Red, Blue
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Red and Blue are only for 3-phase application and must be 16 gauge minimum thickness. No AC control wires can be used with these colors.
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480 VAC – Line (Hot)
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Orange or Yellow
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16 gauge minimum. Consistent within the panel; orange often used if derived from another system.
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480 VAC – Neutral
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White or Gray
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Use only if neutral is present; not typical in 3-phase 480V delta
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Ground (Equipment Grounding Conductor)
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Green or Green with Yellow Stripe
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No other color allowed per NEC
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3. Additional Guidelines
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Control Wiring (AC or DC): Follow voltage-based color scheme above.
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Wiring from External Sources: Any conductor entering the panel from an external power source (not internally derived) must be orange, per NFPA 79.
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Numbering & Labeling: All wires must be numbered or labeled at both ends using heat-shrink tubing, ferrules, or durable wire markers.
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Conductor Bundling: Avoid bundling wires of different voltage classes unless properly separated and insulated.
4. Enforcement
Failure to comply with this policy may result in rework, disciplinary action, or disqualification from working on control panel systems. Periodic inspections will be conducted to ensure adherence. |
