Cable Ampacity

Cable ampacity with all the derating

NEC 310 ampacity isn't just a table lookup — there's temperature correction, conduit fill derating, continuous load factors, and rooftop adders. ekx applies all of them automatically.

What you get

NEC 310 base ampacity

Base ampacity from NEC 310.16 (formerly Table 310.15(B)(16)) for standard conductor sizes.

Temperature correction

Ambient temperature correction factors per NEC 310.15(B)(1) applied automatically.

Conduit fill derating

Adjustment for number of current-carrying conductors per NEC 310.15(C) applied from your conduit configuration.

Continuous load factor

125% continuous load factor per NEC 210.20 and 215.3 applied when loads are continuous.

Adjusted ampacity

Final adjusted ampacity displayed after all correction and adjustment factors.

Conductor selection

Minimum conductor size selected to meet the adjusted ampacity requirement.

Cable ampacity with every factor accounted for

Missing a derating factor means an undersized cable. ekx applies temperature correction, conduit fill derating, and continuous load factors systematically to every cable in your model.

  • Base ampacity from NEC tables, not manual lookup
  • Temperature correction applied from your ambient temperature setting
  • Conduit fill derating applied from your circuit configuration
  • Continuous load factor applied automatically for continuous loads

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Frequently asked questions

Which ampacity table does it use?

NEC 310.16 (Table 310.15(B)(16)) for conductors in raceway or cable. Other tables for specific installation conditions.

How is temperature correction applied?

You set the ambient temperature for each area. ekx looks up the correction factor from NEC 310.15(B)(1) and applies it to the base ampacity.

Does it handle rooftop temperature adders?

Rooftop temperature adders per NEC 310.15(B)(1) can be factored into the ambient temperature setting.

What about continuous vs non-continuous loads?

You designate loads as continuous or non-continuous. The 125% factor per NEC 210.20 is applied to continuous loads when sizing conductors.

Cable ampacity with every NEC factor applied.

Temperature correction, conduit fill, continuous load — all automatic.

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