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Motor Full-Load Amps
(FLA) Calculator

Enter horsepower, voltage, and phase to calculate NEC table FLA, minimum conductor ampacity, branch overcurrent maximum, and overload relay target per NEC Article 430.

Motor circuits are not sized like standard branch circuits. Use NEC table full-load amps as your starting point, then size conductor ampacity, overcurrent protection, overloads, and disconnects independently. This calculator follows live logic from the published TestTalkHQ calculator workflow and keeps the original NEC multipliers intact.

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NEC Table 430.248 - Single-Phase AC Motor Full-Load Currents

FLA values from NEC Table 430.248 for single-phase AC motors.

HP	115V FLA	230V FLA	Min Wire (230V)	Max Breaker (230V, Inverse Time)	Overload Setting (230V)
1/6 HP	4.4A	2.2A	14 AWG	15A	2.75A
1/4 HP	5.8A	2.9A	14 AWG	15A	3.6A
1/3 HP	7.2A	3.6A	14 AWG	15A	4.5A
1/2 HP	9.8A	4.9A	14 AWG	15A	6.1A
3/4 HP	13.8A	6.9A	14 AWG	20A	8.6A
1 HP	16A	8A	14 AWG	20A	10A
1.5 HP	20A	10A	14 AWG	25A	12.5A
2 HP	24A	12A	14 AWG	30A	15A
3 HP	-	17A	12 AWG	45A	21.25A
5 HP	-	28A	10 AWG	70A	35A
7.5 HP	-	40A	8 AWG	100A	50A
10 HP	-	50A	6 AWG	125A	62.5A

NEC Table 430.250 - Three-Phase AC Motor Full-Load Currents

HP	208V	230V	460V	575V	Min Wire (460V)	Max Breaker (460V, Inv. Time)
1/2 HP	2.5A	2.2A	1.1A	0.9A	14 AWG	15A
3/4 HP	3.7A	3.2A	1.6A	1.3A	14 AWG	15A
1 HP	4.8A	4.2A	2.1A	1.7A	14 AWG	15A
1.5 HP	6.9A	6.0A	3.0A	2.4A	14 AWG	15A
2 HP	7.8A	6.8A	3.4A	2.7A	14 AWG	15A
3 HP	11.0A	9.6A	4.8A	3.9A	14 AWG	15A
5 HP	17.5A	15.2A	7.6A	6.1A	14 AWG	20A
7.5 HP	25.3A	22A	11A	9A	14 AWG	30A
10 HP	32.2A	28A	14A	11A	12 AWG	35A
15 HP	48.3A	42A	21A	17A	12 AWG	60A
20 HP	62.1A	54A	27A	22A	10 AWG	70A
25 HP	78.2A	68A	34A	27A	8 AWG	90A
30 HP	92A	80A	40A	32A	8 AWG	100A
40 HP	120A	104A	52A	41A	6 AWG	125A
50 HP	150A	130A	65A	52A	4 AWG	175A

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Tools for motor circuit work

Metering, troubleshooting, and termination tools that support Article 430 field work.

Clamp

Ideal Industries 61-757 Digital Clamp Meter

Measure live motor FLA without lifting conductors
Peak hold support for startup checks
True RMS readings for mixed motor loads

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Meter

Fluke 117 Electricians True RMS Multimeter

Verify motor terminal voltage during startup events
Trusted baseline meter for service diagnostics
CAT III safety rating for control-panel work

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Stripper

Gardner Bender GESP-70 Professional Wire Stripper

Fast prep for motor branch conductors
Improves termination quality at starters
Good fit for repetitive panel builds

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Insulated

Klein Tools 32584INSR 1000V Insulated Screwdriver Set

Safer torque adjustments in energized enclosures
IEC 60900-rated insulation for electrical work
Covers common terminal and lug drive styles

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Finder

Klein Tools ET310 Circuit Breaker Finder

Trace motor branch circuits at distribution panels
Speeds troubleshooting on retrofit jobs
Useful during lockout and labeling workflows

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Motor FLA: Why It Drives Every Motor Circuit Decision

Full-load amps (FLA) is the current a motor draws at rated horsepower and voltage. In motor work, FLA anchors the full branch design: conductor ampacity, branch overcurrent limits, overload settings, and disconnect minimums.

Unlike general branch circuits, NEC Article 430 separates these protective functions. That is why a motor breaker can look oversized while overload protection remains much tighter.

Field Rule Use the NEC table value for branch overcurrent sizing, then verify overload settings against the motor nameplate and service-factor details.

The Four Components You Must Size Separately

Conductor ampacity (430.22): minimum 125% of motor FLA.
Branch overcurrent (430.52): follows breaker/fuse multiplier limits for motor starting inrush.
Overload protection (430.32): protects windings from sustained overload.
Disconnecting means (430.110): minimum 115% of FLA.

Worked Example: 10 HP Three-Phase at 460V

Step 1: Table FLA = 14A.

Step 2: Conductor ampacity minimum = 14 x 1.25 = 17.5A.

Step 3: Inverse-time branch maximum = 14 x 2.50 = 35A.

Step 4: Overload target (SF 1.15+) = 14 x 1.25 = 17.5A.

Step 5: Disconnect minimum = 14 x 1.15 = 16.1A.

Inspection Failure Pattern Treating the branch breaker as overload protection is a frequent failure. Breaker sizing and overload relay sizing serve different functions in Article 430 workflows.

Frequently Asked Questions

What is the difference between FLA and LRA?

FLA is steady running current at rated output. LRA is startup inrush when the rotor is not yet moving, often many times higher than FLA.

Can the branch overcurrent device be less than 250%?

Yes. The multiplier limit is a maximum; if startup is reliable with a smaller setting, that is often preferred.

Do hermetic HVAC compressors use Article 430?

Typically no. Those are generally handled under Article 440 with MCA and MOP nameplate values.

Motor Full-Load Amps
(FLA) Calculator

NEC Table 430.248 - Single-Phase AC Motor Full-Load Currents

NEC Table 430.250 - Three-Phase AC Motor Full-Load Currents