Wire Ampacity & Sizing Calculator
Sizes a conductor from Table 310.16 base ampacity, then applies ambient-temperature correction and current-carrying-conductor bundling adjustment before checking the result against 110.14(C) termination ratings.
What it calculates
- Base ampacity by conductor size, material (copper/aluminum) and insulation temperature rating
- Ambient temperature correction factor
- Adjustment factor for more than 3 current-carrying conductors bundled together
- The smallest standard conductor size that carries the required load after both adjustments
Typical inputs
- Load current or connected VA
- Conductor material and insulation rating
- Ambient temperature
- Number of current-carrying conductors in the raceway or cable
Frequently asked
Does this account for terminal temperature ratings, not just the conductor's own rating?
Yes — 110.14(C) caps the ampacity used for sizing at the terminal's rating (typically 60°C or 75°C for equipment rated 100A or less), even if the conductor insulation itself is rated higher (90°C, for example).
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