Change Summary

• New section added to prevent lighting control conductors from being installed using the same color schemes as the branch circuit grounded conductors and the equipment grounding conductor with a future effective date of January 1, 2022.

Expert Analysis

Traditional lighting systems (typically 120-volt or 277-volt ac) are typically controlled by an “on/off” snap switch or dimmer. It is becoming more and more commonplace to control lighting with low voltage lighting control conductors and devices. This wiring is typically low voltage (Class 2, 12–24-volt dc), providing a pathway for communication of analog or digital signals, such as incoming sensor input data (lighting levels, occupancy sensing conditions, etc.). This low voltage control wiring is typically installed outside branch circuit raceways or alongside cable wiring systems, but is typically installed within the same boxes or enclosures as the nominal voltage wiring.

Multiple shock incidents that have occurred and been reported involving the low voltage lighting control conductors being inadvertently spliced or connected to the grounded (neutral) conductor for the nominal voltage wiring system.

New section 410.69 was added to the 2020 NEC titled, “Identification of Control Conductor Insulation.” This new section will prohibit field-connected control conductor from utilizing the same color identification scheme that is reserved for the grounded branch-circuit conductor (white or gray) or the equipment grounding conductor (green, green with a yellow strip, etc.) where control conductors are spliced, terminated, or connected in the same luminaire or enclosure as the branchcircuit conductors. A new informational note was also added to point the user of the Code toward 200.6 for identification of the grounded conductor and 250.119 for identification of an equipment grounding conductor. The identification of the control conductors using colors typically identified with the branch circuit ungrounded conductors was not affected by this new provision.

Before the electrical industry can start to process this change, the industry will need to establish a new standard to replace the historic “purple and gray” conductors that have been used universally. A future effective date of January 1, 2022 has been incorporated into this new requirement to enable manufacturers to comply and sell-off existing inventory.

An exception was also added for this rule permitting a field-connected gray-colored control conductor if the insulation is permanently re-identified by marking tape, painting, or other effective means at its termination and at each location where the conductor is visible and accessible. This re-identification is required to “encircle the insulation” and the color used must be any color other than white, gray, or green.

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