ekx
Motor Circuits

Motor feeder sizing that follows NEC 430

Motor circuits have special sizing rules — 125% FLC for conductors, maximum OCPD tables, service factor adjustments. ekx handles all of it automatically the moment you place a motor on the diagram.

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What you get

NEC 430 conductor sizing

Conductors sized at 125% of motor FLC per NEC 430.22, with temperature correction and derating.

OCPD sizing per NEC 430.52

Maximum overcurrent protection device sizes selected from NEC Table 430.52 by motor type.

Motor FLC tables

Full-load current values from NEC Tables 430.247–250 applied automatically by HP and voltage.

Voltage drop check

Voltage drop at the motor terminals calculated and flagged if it exceeds your threshold.

Overload protection

Motor overload sizing per NEC 430.32 based on nameplate FLA and service factor.

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Change motor HP, voltage, or type and the entire feeder resizes instantly.

Motor circuit sizing without the NEC lookup marathon

Sizing a motor feeder means cross-referencing FLC tables, conductor ampacity, OCPD maximums, and overload sizing. ekx does all four the moment you specify the motor.

  • Place a motor, specify HP and voltage — feeder sizes automatically
  • NEC 430 FLC tables, conductor rules, and OCPD limits all applied
  • Change motor HP and every component in the feeder adjusts
  • Voltage drop at the motor terminals calculated as part of load flow

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Frequently asked questions

Which NEC tables does it use for motor FLC?

NEC Tables 430.247 (DC), 430.248 (single-phase), 430.249 (two-phase), and 430.250 (three-phase) are used based on motor type and voltage.

Does it handle Design B, C, D motors?

Motor type affects OCPD sizing per NEC Table 430.52. You can specify the motor type and ekx selects the correct maximum OCPD percentage.

What about multi-motor feeders?

ekx sizes branch circuits for individual motors. For feeders supplying multiple motors, the system considers the sum of FLCs plus the largest motor's contribution per NEC 430.24.

Can I override the auto-sized values?

Yes. Any auto-sized value — conductor, OCPD, or overload — can be overridden. The system flags if your override violates NEC maximums.

Related resources

Cable Sizing CalculatorBreaker Sizing CalculatorVoltage Drop CalculatorConduit Fill CalculatorNEC Compliance Software

Motor feeders sized per NEC 430, automatically.

FLC tables, conductor sizing, OCPD limits — all handled.

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