Reference
Technical Reference Tables
Motor FLA, wire sizing, breaker sizing, and NEC quick reference. Print these and put them next to your panel.
Phase Converter Sizing — Quick Reference
| Largest Motor HP | All Other Loads HP | Total (2× largest + others) | Phoenix Model |
|---|---|---|---|
| 1 HP | 0 | 2 HP | GP3NL |
| 2 HP | 0 | 4 HP | GP5NL |
| 3 HP | 0 | 6 HP | GP7NL |
| 5 HP | 0 | 10 HP | GP10NL |
| 5 HP | 2 HP | 12 HP | GP15NL |
| 7.5 HP | 0 | 15 HP | GP15NL |
| 10 HP | 0 | 20 HP | GP20NL |
| 10 HP | 3 HP | 23 HP | GP25NL |
| 15 HP | 0 | 30 HP | GP30NL |
| 20 HP | 0 | 40 HP | GP40NL |
| 25 HP | 0 | 50 HP | GP50NL |
Compressor loads: use 3× HP and NLA model. Example: 5 HP compressor → GP15NLA.
Three-Phase Motor Full-Load Amps (NEC Table 430.250)
| HP | 230V FLA | 460V FLA | 575V FLA |
|---|---|---|---|
| 0.5 | 2.2 | 1.1 | 0.9 |
| 0.75 | 3.2 | 1.6 | 1.3 |
| 1 | 4.2 | 2.1 | 1.7 |
| 1.5 | 6.0 | 3.0 | 2.4 |
| 2 | 6.8 | 3.4 | 2.7 |
| 3 | 9.6 | 4.8 | 3.9 |
| 5 | 15.2 | 7.6 | 6.1 |
| 7.5 | 22 | 11 | 9 |
| 10 | 28 | 14 | 11 |
| 15 | 42 | 21 | 17 |
| 20 | 54 | 27 | 22 |
| 25 | 68 | 34 | 27 |
| 30 | 80 | 40 | 32 |
| 40 | 104 | 52 | 41 |
| 50 | 130 | 65 | 52 |
| 60 | 154 | 77 | 62 |
| 75 | 192 | 96 | 77 |
| 100 | 248 | 124 | 99 |
Single-Phase Motor Full-Load Amps (NEC Table 430.248)
| HP | 115V FLA | 200V FLA | 208V FLA | 230V FLA |
|---|---|---|---|---|
| 0.17 (1/6) | 4.4 | 2.5 | 2.4 | 2.2 |
| 0.25 (1/4) | 5.8 | 3.3 | 3.2 | 2.9 |
| 0.33 (1/3) | 7.2 | 4.1 | 4.0 | 3.6 |
| 0.5 | 9.8 | 5.6 | 5.4 | 4.9 |
| 0.75 | 13.8 | 7.9 | 7.6 | 6.9 |
| 1 | 16 | 9.2 | 8.8 | 8 |
| 1.5 | 20 | 11.5 | 11 | 10 |
| 2 | 24 | 13.8 | 13.2 | 12 |
| 3 | 34 | 19.6 | 18.7 | 17 |
| 5 | 56 | 32.2 | 30.8 | 28 |
| 7.5 | 80 | 46 | 44 | 40 |
| 10 | 100 | 57.5 | 55 | 50 |
Phase Converter Input — Breaker & Wire Sizing
Per NEC 455.7: phase converter input conductors sized at 250% of rated input current. Breaker sized at 250% of rated input current (round up to next standard size).
| Converter HP | Input FLA (230V) | Conductor (250%) | Min Breaker | Wire Size (Cu, 75°C) |
|---|---|---|---|---|
| 3 HP | ~10A | 25A | 30A | 10 AWG |
| 5 HP | ~16A | 40A | 40A | 8 AWG |
| 7.5 HP | ~22A | 55A | 60A | 6 AWG |
| 10 HP | ~28A | 70A | 70A | 4 AWG |
| 15 HP | ~42A | 105A | 110A | 2 AWG |
| 20 HP | ~54A | 135A | 150A | 1 AWG |
| 25 HP | ~68A | 170A | 175A | 2/0 AWG |
| 30 HP | ~80A | 200A | 200A | 3/0 AWG |
| 40 HP | ~104A | 260A | 300A | 350 kcmil |
| 50 HP | ~130A | 325A | 350A | 500 kcmil |
Always verify with your licensed electrician. Actual sizing depends on conduit fill, ambient temperature, run length, and local code amendments.
HP to kVA Conversion
| HP | kW (approx) | kVA at 0.85 PF | kVA at 0.90 PF |
|---|---|---|---|
| 1 | 0.746 | 0.88 | 0.83 |
| 3 | 2.24 | 2.63 | 2.49 |
| 5 | 3.73 | 4.39 | 4.14 |
| 7.5 | 5.59 | 6.58 | 6.21 |
| 10 | 7.46 | 8.78 | 8.29 |
| 15 | 11.19 | 13.17 | 12.43 |
| 20 | 14.92 | 17.55 | 16.58 |
| 25 | 18.65 | 21.94 | 20.72 |
| 30 | 22.37 | 26.32 | 24.86 |
| 40 | 29.83 | 35.10 | 33.14 |
| 50 | 37.28 | 43.86 | 41.43 |
NEC Article 455 — Phase Converter Quick Reference
| Section | Requirement |
|---|---|
| 455.4 | Must be identified for the type of load (static or rotary) |
| 455.6(A) | Input conductors sized at 250% of rated input current |
| 455.6(B) | Output conductors sized at 125% of load FLA |
| 455.7 | Overcurrent protection: 250% of rated input current |
| 455.8(A) | Converter must be grounded per Article 250 |
| 455.8(C) | No conductor from converter output may be connected to system neutral |
| 455.10 | Disconnecting means within sight of converter and capable of locking open |
| 455.11 | Marking: must show HP, voltage, current, phases, frequency |
Voltage Balance Limits
| Application | Max Recommended Imbalance |
|---|---|
| Standard motors (NEMA MG-1) | ≤ 5% |
| CNC machines / VFD drives | ≤ 2–3% (check machine manual) |
| Sensitive servo drives | ≤ 2% |
| Phoenix NL/PL output at rated load | < 2% |
Voltage imbalance = (max deviation from average ÷ average) × 100. Measure leg-to-leg under full load for an accurate reading.