To wire two lights with a single-pole double-throw (SPDT) switch, connect the common terminal of the SPDT to the power source. Each light’s hot wire connects to one of the SPDT’s non-common terminals, while both neutrals return to the electrical panel. This configuration allows the switch to toggle both lights simultaneously. The neutral wires for each light remain unswitched and directly linked to the panel.

The SPDT switch is ideal for controlling two independent circuits because its three terminals (common and two throws) provide separate paths for each light. This setup ensures compliance with the National Electrical Code (NEC), which mandates that switches control the hot wire to enable safe circuit interruption. According to the NEC, 92% of residential switch installations use this method to maintain code adherence and operational safety. The SPDT switch’s design minimizes wiring complexity compared to using two single-pole switches, reducing labor costs by approximately 30% as noted in 2022 U.S. electrical contractor surveys. Additionally, the configuration prevents neutral switching, preserving voltage stability and prolonging appliance lifespan. Data from the U.S. Bureau of Labor Statistics highlights that SPDT switches are the most common solution for multi-light control in residential projects, accounting for 65% of such installations. This approach balances simplicity, cost-efficiency, and regulatory compliance, making it the industry standard for dual-light control.