What Size Wire for Well Pump? — Complete Wiring Guide
A Well Pump requires 12 AWG copper (up to 1 HP) or 10 AWG (1.5-2 HP) with a 20A (1 HP) or 30A (2 HP) on a 240V dedicated circuit. Here is the complete NEC-compliant wiring guide.
Well Pump Wiring Details
Submersible well pumps are motor loads, so wiring follows NEC Article 430 motor rules rather than simple load calculations. A 1 HP 240V pump draws about 8 amps running but can pull 40-50 amps during startup. The wire must handle the running current, while the breaker must be large enough to handle startup inrush without tripping. For a 1 HP pump: 12 AWG wire, 20A breaker. For 1.5 HP: 10 AWG wire, 25A breaker. For 2 HP: 10 AWG wire, 30A breaker. Check motor nameplate FLA (Full Load Amps) for exact sizing.
NEC Code Reference
The wiring requirements for a Well Pump are governed by NEC Article 430 (motors). 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
Deep well pumps (200+ feet) face significant voltage drop in the wire running down the well casing. Many pump installers upsize the downhole wire by 1-2 gauges to compensate. A 10% voltage drop at the pump motor reduces its efficiency by 20% and significantly shortens motor life. Always verify voltage at the pump, not just at the pressure switch.
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.