NEC Requirements



NEC 409.2(A)(2)

Conductors of different systems, circuits, or classes of voltage shall not be placed in the same raceway, enclosure, or cabinet unless specifically permitted otherwise in this Code.

NEC 409.2(C)(2)

Where conductors of different classes of voltage or circuits are installed in both raceways and cables within the same enclosure, raceway entrance fittings or sealing fittings that maintain separation between the different classes of voltage or circuits shall be installed.

UL Requirements



UL 508A: Industrial Control Panels

Section 36.8 requires that live parts of lower voltage circuits shall be separated from live parts of higher voltage circuits by suitable barriers or isolation materials. Section 36.9 prohibits the installation of uninsulated conductors of different voltage classes in the same raceway or enclosure unless suitably isolated.

Guidelines for Circuit/Component Isolation

Install physical barriers between high voltage and low voltage circuits, such as metal barriers, insulating spacers, or terminal blocks. Use shielded cables or conduits to separate high voltage and low voltage conductors. Maintain a minimum separation distance between high voltage and low voltage conductors as specified in NEC Table 310.16 or UL 508A. Label conductors and enclosures clearly to indicate voltage levels and circuit function. Ensure that all electrical components are properly insulated and protected from potential shorts or ground faults.

Additional Considerations: The specific isolation requirements may vary depending on the voltage level, type of equipment, and application. Refer to the manufacturer's instructions and consult with a qualified electrician for guidance on specific isolation measures.* Follow all applicable safety regulations and codes to ensure the proper and safe installation of electrical equipment. Flag for review