power

Determine minimum wire gauge using NEC Table 310.16 ampacity ratings with full derating. Looks up base ampacity for copper or aluminum conductors at 60°C, 75°C, or 90°C insulation rating, then applies NEC 310.15(C)(1) ambient temperature correction and NEC 310.15(C)(2) conductor count adjustment. Automatically applies the 125% continuous load factor per NEC 210.20(A) when flagged. Returns the minimum AWG that meets the derated requirement, plus a comparison table of all gauges. Different from wire_gauge which focuses on voltage drop — use both together for complete wire sizing. Essential for residential panels, commercial feeders, solar arrays, and EV charging installations.

post/api/wire_ampacity

Request

  • Base URL: https://calc.engineer
  • URL: https://calc.engineer/api/wire_ampacity
  • Auth: none declared

Request body

current_ampsnumber required

Required circuit current in amperes. Use 125% of continuous load per NEC 210.20(A).

conductor'copper' | 'aluminum'

Conductor material. Copper has higher ampacity; aluminum is lighter and cheaper for large feeders.

insulation'60' | '75' | '90'

Insulation temperature rating in °C. 60=TW/UF-B, 75=THW/THWN/XHHW (most common), 90=THHN/THWN-2.

ambient_temp_cnumber

Ambient temperature in °C. NEC base is 30°C. Higher temps require derating. Typical: 30 (indoor), 40 (attic/hot), 45+ (rooftop conduit).

conductors_in_racewaynumber

Number of current-carrying conductors in a single raceway or cable. More than 3 requires derating per NEC 310.15(C)(2).

continuous_loadboolean

Whether the load operates continuously (3+ hours). NEC requires 125% sizing for continuous loads. Set false for intermittent loads.

Response

Computed result for wire_ampacity

toolstring required
versionstring required
computed_atstring date-time required

Changes

No recorded changes to this operation across all 1 revision of this API.