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Tuesday, October 11, 2022
Question:
Hi CQD, my question is can conductors supplied by two(2) different system voltages like 277/480V and 120/240V be installed in same conduit? Is this permitted by the Code? If so what Section?
Thanks,
Robert De Leon :)
A
Answer:
Robert, thanks for your question, and the answer is yes, the 2020 edition of the NEC™️ permits the installation of conductors from two(2) different systems in the same conduit or raceway. This type of installation comes with additional color coding, marking, and labeling requirements.
- For Ungrounded Conductors - Where a premises wiring system has branch circuits supplied from more than one nominal voltage system, Section 210.5(C)(1)(a)&(b) requires a unique color coding(by phase) to be established and used for the ungrounded conductors of each system. This color coding then must be consistent at all terminations, connections, and splice points. The color coding selected for each system must be posted at each distribution point/branch circuit panelboard in accordance with Section 210.5(C)(1)(b). Section 210.5(C) applies regardless if the conductors are in the same conduit or raceway.
- For Grounded Conductors - Section 200.6(D) requires the grounded conductors of different systems installed in the same raceway, cable, box, auxiliary gutter, or other types of enclosure, be uniquely identified by system using one of the means specified in Section 200.6(D)(1)-(3). Section 200.6(D) only applies if the two voltage system conductors are in the same raceway, enclosure, conduit, etc.