What Size Wire for a Sump Pump?
Wire and breaker sizing for a Sump Pump — the typical 120V circuit, plus the code details (NEC 310.16) that change the answer.
Calculations are built on the 2023 National Electrical Code (NEC) and cross-checked against the published code tables. How we verify. Last reviewed June 2026.
On a 15A 120V circuit at 75°C terminations.
Protected by a 15A breaker (NEC 240.6).
GFCI required. The 2023 NEC (210.8(D) for specific appliances, 210.8(A) for kitchen/outdoor receptacles) requires GFCI protection here. Verify the code edition your jurisdiction has adopted.
Sump Pump Circuit Details
- Most sump pumps run on a dedicated 120V 15A or 20A circuit (14 or 12 AWG).
- GFCI protection is required for sump pumps in unfinished basements/crawlspaces.
- A ⅓–½ HP pump draws roughly 4–10A.
Long run to your sump pump?
Over distance, voltage drop can require a larger wire than the table above. See the 15A wire size by distance:
Size it for your exact install
Open the calculator pre-filled with 15A at 120V to add distance, material and temperature.