Wire Ampacity Calculator
Find a conductor’s derated ampacity. WireCoder starts from NEC Table 310.16, applies the ambient temperature correction (310.15(B)(1)) and the adjustment for more than three current-carrying conductors (310.15(C)(1)).
How it works
Derated ampacity = base ampacity (Table 310.16) × temperature correction factor × bundling adjustment factor. Each factor is shown so you can check the work.
Frequently asked questions
Does it include temperature correction?
Yes — full Table 310.15(B)(1) ambient correction by insulation rating (60/75/90°C).
What about more than 3 conductors?
The 310.15(C)(1) adjustment is applied automatically (80% for 4–6, 70% for 7–9, and so on).