The 2023 National Electric Code (NEC) has a new requirement that prohibits battery-powered wall light switches unless they have a back up power supply. Battery powered wall switches have become a popular form of wireless lighting control, whether that be Bluetooth, Zigbee, Z-Wave, LoRa, or a proprietary wireless technology.
The exact 2023 NEC code language is:
“210.70 Lighting Outlets Required. Lighting outlets shall be installed where specified in 210.70(A), (B), and (C). The switch or wall-mounted control device shall not rely exclusively on a battery unless a means is provided for automatically energizing the lighting outlets upon battery failure.”
This section, 210.70, primarily applies to living spaces, such as homes, apartments, and hotel guest rooms. Its intent is to protect inhabitants’ ability to safely exit a building during an emergency, and avoid a dead battery preventing lights from turning on. Having utility power present, but no way to energize the lights in a room because of a bad battery in a wireless light switch, is a hazard for occupants.
EnOcean Alliance is promoting their solution, wireless light switches that harvest the motion energy of flipping the light switch to generate a pulse of electricity that is enough to send a radio signal to the light’s receiver. See the images at the bottom.
More information is available in the EnOcean Alliance white paper here.
EnOcean energy harvesting module and energy harvesting powered wireless light switches. Images: EnOcean Alliance
The new Code language does not prohibit battery-only wall light switches as the title of this article suggests. The Code does allow the switch to rely exclusively on a battery if a means is provided to automatically energize the lighting upon battery failure. A simple circuit that automatically turns the lights ON when the battery level is low (like a smoke detector that chirps when the battery level is low) and prevents the switch from being used to turn the lights OFF until the battery is replaced would seemingly comply with the new Code requirements. With that being said, we began offering self-powered batteryless lighting control devices in 2009 because they are better for the environment than battery-powered devices and require no maintenance to ensure reliability.