What Size Wire for Bathroom Exhaust Fan? — Complete Wiring Guide
A Bathroom Exhaust Fan requires 14 AWG (can share lighting circuit) with a 15A on a 120V (shared with lighting OK) circuit. Here is the complete NEC-compliant wiring guide.
Bathroom Exhaust Fan Wiring Details
Bathroom exhaust fans draw very little power — typically 0.2-0.5 amps. They can share the bathroom lighting circuit without any issues. NEC 210.11(C)(3) requires at least one 20A circuit for bathroom receptacles (GFCI outlets), but the exhaust fan and lighting can be on a separate 15A circuit. Many electricians wire the fan and vanity light on the same switch leg.
NEC Code Reference
The wiring requirements for a Bathroom Exhaust Fan are governed by NEC 210.11(C)(3). Always check the appliance nameplate for specific electrical requirements — the manufacturer's specifications take precedence over general guidelines. Your local AHJ (Authority Having Jurisdiction) may have additional requirements beyond the NEC.
Pro Tip
For a bathroom with a fan/heater combo unit, the heater portion (typically 1,000-1,500W) changes everything — it needs a dedicated 20A circuit with 12 AWG wire. Read the installation manual carefully and never put a heater fan on the lighting circuit.
Disclaimer: This guide is for reference only. All electrical work must be performed by or verified by a licensed electrician. Local codes may differ from NEC.