THHN/THWN Wire 12 AWG electrical wire is a conductor system designed for power distribution, lighting, and control circuits. Insulation materials are rated for voltage, temperature, and environmental exposure conditions. All installations must comply with National Electrical Code (NEC) requirements regarding circuit protection, grounding, and sizing. Proper support, clearance, and identification facilitate maintenance and troubleshooting. Installation in conduit provides mechanical protection and facilitates future wire replacement.