UL Listing
A certification from Underwriters Laboratories indicating that a product has been tested and meets safety standards. Solar panels need UL 61730; inverters need UL 1741; batteries need UL 9540.
Why It Matters
Only UL-listed equipment qualifies for utility interconnection, building permits, and insurance coverage. Never install non-UL-listed solar or battery equipment.
Related Terms
NEC (National Electrical Code)
The U.S. standard for electrical installation safety (NFPA 70). Article 690 specifically covers solar PV systems, including wiring, grounding, labeling, and rapid shutdown requirements.
Electrical Inspection
A review by a licensed inspector to verify that electrical work meets National Electrical Code (NEC) requirements. Required before utility interconnection of solar systems and after panel upgrades.