What size wire do I need for a 50 amp hot tub?
For a hot tub fed by NM-B (Romex), NEC 334.80 forces sizing from the 60°C column, so you need #6 AWG copper for a continuous 50 A load. If you run THHN/THWN-2 in conduit you can drop to #8 AWG copper because terminations are listed at 75°C and the 75°C column allows 50 A on #8. Always confirm the spa-pack manual — many require GFCI protection and a specific minimum wire size that supersedes NEC.
Answers
- What wire size do I need for a 50-amp circuit?
- Does NEC require 75°C or 90°C ampacity?
- How do I derate wire for high ambient temperature?
- Is romex inside conduit derated?
- Do I have to upsize wire for a long run?
- Does a VFD or EV charger count as a continuous load?
- How many wires can I put in conduit before I have to derate?