Change Summary

• Dimmer-controlled receptacle provisions have been deleted.

Expert Analysis

During the 2014 Code revision cycle, new rules were added at 406.15 permitting certain receptacles to be controlled by a dimmer under specific conditions. In conjunction with 404.15(E), dimmer switches are not permitted to control receptacle outlets. Dimmer switches are to be used only to control permanently installed incandescent luminaires, unless listed for the control of other loads and installed accordingly. This 2014 NEC addition at 406.15 allowed a receptacle supplying lighting loads to be connected to a dimmer if the plug/receptacle combination is a nonstandard configuration type and specifically listed and identified for each such unique combination.

This requirement was directed at 120-volt cord- and plug-connected lighting, such as LED-type rope lighting. According to the substantiation for this 2014 NEC addition, some of the manufacturers of these lighting sources provide a dimming feature that is listed with their product. Clear, concise Code language was needed to ensure standard grade receptacles were not being controlled from any dimming or voltage dropping device. For the 2017 NEC, 406.15 was deleted in it’s entirely. The substantiation for the deletion of 406.15 stated that this issue was better handled by the listing and product standards for these unique and specific products. Perhaps the rules were too broad in nature in specifying an undefined type of plug/receptacle connector pairing related to cord-and-plug connected load and dimmer incompatibility.

The creation of 406.15 was an attempt to solve a specific problem associated with emerging and evolving new technology, such as LED. As noble as the concept might have been, the addition of 406.15 did not solve this problem. Once again, the solution is better found with the listing and product standards for these unique and specific products.

Leviton Comment
Although 406.15 was deleted in the 2017 NEC, 404.14(E) remains and it dictates that “General use dimmer switches shall be used only to control permanently installed incandescent luminaires unless listed for the control of other loads and installed accordingly.”