Motor Full-Load Amps Chart
Look up motor full-load current by horsepower, voltage and phase — and get the 125% conductor ampacity in the same step. Covers 1/6 hp to 200 hp.
Every motor circuit starts with one number: how much current the machine actually pulls when it is working. Get it wrong and you either trip a breaker every Monday morning or run undersized conductors that get warm and stay warm. The tables below are the reference values used across North American motor work, plus the sizing rules that sit on top of them.
Three-Phase Motor Full-Load Amps
Induction-type squirrel-cage and wound-rotor motors running at usual speeds with normal torque characteristics. Values as published in NEC Table 430.250.
| HP | 208 V | 230 V | 460 V | 575 V |
|---|---|---|---|---|
| ½ | 2.4 | 2.2 | 1.1 | 0.9 |
| ¾ | 3.5 | 3.2 | 1.6 | 1.3 |
| 1 | 4.6 | 4.2 | 2.1 | 1.7 |
| 1½ | 6.6 | 6.0 | 3.0 | 2.4 |
| 2 | 7.5 | 6.8 | 3.4 | 2.7 |
| 3 | 10.6 | 9.6 | 4.8 | 3.9 |
| 5 | 16.7 | 15.2 | 7.6 | 6.1 |
| 7½ | 24.2 | 22 | 11 | 9 |
| 10 | 30.8 | 28 | 14 | 11 |
| 15 | 46.2 | 42 | 21 | 17 |
| 20 | 59.4 | 54 | 27 | 22 |
| 25 | 74.8 | 68 | 34 | 27 |
| 30 | 88 | 80 | 40 | 32 |
| 40 | 114 | 104 | 52 | 41 |
| 50 | 143 | 130 | 65 | 52 |
| 60 | 169 | 154 | 77 | 62 |
| 75 | 211 | 192 | 96 | 77 |
| 100 | 273 | 248 | 124 | 99 |
| 125 | 343 | 312 | 156 | 125 |
| 150 | 396 | 360 | 180 | 144 |
| 200 | 528 | 480 | 240 | 192 |
Single-Phase Motor Full-Load Amps
Values as published in NEC Table 430.248. Note how quickly the current climbs — a 10 hp single-phase motor at 115 V pulls 100 A, which is why anything above about 5 hp is almost always specified three-phase.
| HP | 115 V | 208 V | 230 V |
|---|---|---|---|
| 1/6 | 4.4 | 2.4 | 2.2 |
| ¼ | 5.8 | 3.2 | 2.9 |
| 1/3 | 7.2 | 4.0 | 3.6 |
| ½ | 9.8 | 5.4 | 4.9 |
| ¾ | 13.8 | 7.6 | 6.9 |
| 1 | 16 | 8.8 | 8.0 |
| 1½ | 20 | 11 | 10 |
| 2 | 24 | 13.2 | 12 |
| 3 | 34 | 18.7 | 17 |
| 5 | 56 | 30.8 | 28 |
| 7½ | 80 | 44 | 40 |
| 10 | 100 | 55 | 50 |
Nameplate FLA vs Table FLC — The Distinction That Matters
Open any motor-circuit design and you'll find two current values in play. Mixing them up is the single most common error in this work.
| Number | Where it comes from | What it sizes |
|---|---|---|
| Table FLC | NEC 430.248 / 430.250 by hp and voltage | Branch-circuit conductors, short-circuit and ground-fault protection, disconnect rating, feeder calculations |
| Nameplate FLA | Stamped on the specific motor by its manufacturer | Running overload protection only |
The logic is deliberate. Conductors and breakers are sized from a standardised table so that a motor swap doesn't invalidate the installation, while the overload relay protects that particular machine and therefore follows its own nameplate. A high-efficiency motor with a nameplate FLA well below the table value still gets table-sized wire.
Service factor changes the overload setting
A nameplate marked SF 1.15 is permitted a higher overload trip point than one marked 1.0, because the manufacturer has designed in continuous overload headroom. Check the nameplate before setting a relay — the same frame size can ship either way.
Conductor and Protection Sizing Rules
Once you've the table current, the standard sequence for a single continuous-duty motor is:
- Conductors: minimum 125% of table FLC, then correct for ambient temperature, conduit fill and voltage drop over the run.
- Overload protection: based on nameplate FLA and service factor, not the table.
- Short-circuit / ground-fault protection: sized well above FLC so it rides through starting inrush, with permitted multipliers depending on device type.
- Disconnect: rated at or above 115% of full-load current.
The calculator above returns the 125% conductor figure alongside the base current so you can go straight to an ampacity table.
Starting Current Is a Different Animal
Full-load amps describe steady running. A direct-on-line motor start pulls several times that — commonly six to eight times FLC for a fraction of a second, with the exact multiple set by the NEMA code letter on the nameplate. That inrush is why:
- Short-circuit protection is deliberately sized far above the running current
- Standard breakers nuisance-trip where a motor-rated device wouldn't
- Soft starters and variable frequency drives exist at all
If you're sizing a generator or a transformer rather than a branch circuit, starting kVA is the governing number, not FLC.
Sanity-Check Rules of Thumb
For three-phase motors, useful for spotting a typo — never for design:
- 480 V: ≈ 1.25 A per hp
- 230 V: ≈ 2.5 A per hp
- 575 V: ≈ 1.0 A per hp
Check one against the table: a 50 hp motor at 460 V. Rule of thumb says 62 A; the table says 65 A. Close enough to catch a decimal-point error, not close enough to pull wire from.
Related Tools
To work from measured current instead of horsepower, use amps to HP, or go the other way with HP to amps. For power rather than current see HP to kW three-phase, standard frame ratings in the motor HP chart, and shaft output in the electric motor HP calculator.
Frequently Asked Questions
Three-phase: 15.2 A at 230 V, 7.6 A at 460 V. Single-phase: about 28 A at 230 V or 56 A at 115 V.
68 A at 230 V, 34 A at 460 V, 27 A at 575 V — three-phase. Conductors are sized at 125% of those.
Both. Table FLC sizes conductors, short-circuit protection and disconnects. Nameplate FLA sizes the running overload. Swapping them is the classic motor-circuit mistake.
Power = √3 × V × I × PF. For the same shaft output, doubling voltage halves current — which is exactly why long runs are distributed at higher voltage.
Three-phase: about 1.25 A/hp at 480 V, 2.5 A/hp at 230 V, 1 A/hp at 575 V. Sanity checks only — never design values.
Start at 125% of table FLC, then correct for ambient temperature, conduit fill and voltage drop over the run length.
Motor-side current stays near nameplate at full load, but drive input current, harmonics and conductor sizing follow the drive manufacturer's data, not the plain motor table.
30.8 A. The 208 V column runs about 10% above 230 V for the same horsepower.