Submersible Well Pump Breaker & Wire Size
Free online tool • 2026 NEC Compliant
Submersible well pump circuits are sized as motor circuits under NEC Article 430, not as simple appliance loads. The breaker and wire size depend on the pump motor's horsepower and full-load amperage (FLA), sized at 125% of FLA per NEC 430.22, then rounded to the nearest standard breaker size per NEC 430.52. Most residential 1/2 HP to 1.5 HP submersible pumps run on 240V circuits ranging from 15A to 30A — always confirm against the pump's specific nameplate FLA rather than horsepower alone.
Recommended Sizing
NEC Standard SizeBreaker Type: Standard Inverse-Time
NEC Reference Note: 125% multiplier applied for continuous loads per NEC 210.20(A).
How to Use This Calculator
Find motor horsepower and FLA
Check the pump's nameplate or use NEC Table 430.248 for standard single-phase motor full-load current.
Apply 125% continuous factor
Multiply the FLA by 1.25 to find the minimum required breaker size.
Round to standard breaker size
Round up to the next standard breaker rating per NEC 430.52.
Check wire size for voltage drop
For long runs to the wellhead, upsize wire beyond the minimum ampacity requirement to limit voltage drop.
Frequently Asked Questions
What size breaker do I need for a well pump?
It depends on motor horsepower and full-load amps (FLA). Common residential 240V submersible pumps: 1/2 HP is often a 15A breaker, 3/4–1 HP is often 15–20A, and 1.5–2 HP can require 20–30A. Always size from the pump's nameplate FLA at 125% per NEC 430.22, not from horsepower tables alone.
What wire size do I need for a well pump?
Wire size depends on the pump's FLA and the length of the run — long runs from the panel to the wellhead may require upsizing beyond the minimum ampacity to control voltage drop. A 15A circuit typically uses 14 AWG minimum, but many well installations use 12 AWG or larger due to distance.
Does a well pump need a dedicated circuit?
Yes. Submersible well pump motors require a dedicated branch circuit sized specifically to the motor, per NEC Article 430, along with a disconnecting means within sight of the pump control box or at the wellhead.
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