What Size Wire for a Hot Tub?
Wire and breaker sizing for a Hot Tub — the typical 240V circuit, plus the code details (NEC Article 680) 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.
Copper
8 AWG
On a 50A 240V circuit at 75°C terminations. 60°C terminations: 6.
Aluminum
6
Protected by a 50A breaker (NEC 240.6).
Voltage
240V
Breaker
50A
Connection
Hardwired
GFCI
Required
GFCI required. NEC Article 680 requires GFCI protection and a disconnect within sight for pool/spa equipment.
Hot Tub Circuit Details
- Most plug-and-play and built-in spas need a 50A GFCI-protected 240V circuit — 8 AWG copper minimum (75°C); 6 AWG is commonly used for the continuous heater load and 60°C terminations.
- NEC 680 requires a GFCI disconnect within sight of the tub, at least 5 ft away.
- Larger spas require a 60A circuit (6 AWG copper); confirm on the equipment label.
Long run to your hot tub?
Over distance, voltage drop can require a larger wire than the table above. See the 50A wire size by distance:
Size it for your exact install
Open the calculator pre-filled with 50A at 240V to add distance, material and temperature.