High-voltage and low-voltage wiring can share a cabinet if properly separated, insulated, and labeled, following NEC guidelines and best practices.

Separation and Safety

High-voltage wiring (over 50V) and low-voltage wiring (50V or less) should not be mixed in the same conduit due to risks of electrical shock, fire, insulation breakdown, and signal interference . Within a cabinet, separation can be achieved by:

• Physical barriers: Use plastic or metal dividers to keep high-voltage and low-voltage wires apart .
• Dedicated sides: Assign one side of the cabinet for high-voltage circuits and the other for low-voltage circuits, keeping them as far apart as practical .
• Separate knockouts: Feed high-voltage and low-voltage wires through different conduit knockouts to maintain separation .

Wire Ratings and Insulation

All wires in the enclosure should have insulation rated for the highest voltage present. For example, if combining 120V AC and 24V DC circuits, low-voltage wires should be rated for at least 600V to comply with NEC 300.3(C), . Using appropriately sized conductors and color-coded wires helps prevent confusion and ensures safety during maintenance.

Labeling and Documentation

• Label all wires clearly to indicate voltage and function.
• Maintain a schematic or wiring diagram inside or near the cabinet for reference.
• Color-code wires according to standard conventions (e.g., black/red for high-voltage, blue/white for low-voltage).

Practical Considerations

• Avoid running low-voltage control wiring alongside branch power wiring in the same tray or conduit to prevent electromagnetic interference .
• If a device requires both voltages (e.g., a relay with a 24V coil and 120V load), ensure the wiring is physically separated within the enclosure and that the low-voltage side uses wires rated for the higher voltage .
• Follow manufacturer instructions for equipment that combines high and low voltage, as many panels provide dedicated headers and conduit access points for each voltage type .

Summary

To safely lay out high-voltage and low-voltage circuits in the same cabinet:

1. Use physical separation or barriers.
2. Feed wires through separate knockouts.
3. Ensure all wires are rated for the highest voltage present.
4. Label and color-code all wiring.
5. Keep schematics accessible and follow manufacturer guidelines.
6. Consult the local Authority Having Jurisdiction (AHJ) to confirm compliance with NEC and local codes . Following these practices ensures safety, reduces interference, and maintains code compliance while allowing both high-voltage and low-voltage circuits to coexist in the same cabinet.