Single-phase input wire size
Sizing the 240V single-phase feeder from your service panel to the converter. Figures assume 240V, copper conductors, 75°C terminations and a run under about 100 ft.
| Converter / motor | Approx. input amps | Breaker | Copper conductor |
|---|---|---|---|
| 3 HP | ~20 A | 30 A | 10 AWG |
| 5 HP | ~30 A | 40–50 A | 8 AWG |
| 7.5 HP | ~44 A | 60 A | 6 AWG |
| 10 HP | ~58 A | 70–80 A | 4 AWG |
| 15 HP | ~85 A | 100 A | 3 AWG |
| 20 HP | ~110 A | 125 A | 1 AWG |
| 25 HP | ~135 A | 150 A | 1/0 AWG |
| 30 HP | ~160 A | 175–200 A | 2/0 AWG |
Notes for the input side
- The converter draws its rated input current plus whatever your machines pull, so size for the total running load, not just the converter.
- A disconnect within sight of the converter is required in most jurisdictions — plan for it in your layout.
- Two hot legs plus an equipment grounding conductor. A neutral is only needed if you are feeding 120V circuits from a separate source.
- Inrush on start-up is brief but large. If a correctly sized breaker nuisance-trips, ask us about breaker curve type before increasing the size.
- For runs longer than about 100 ft, increase the conductor one size for every additional 100 ft to keep voltage drop under 3%.
Planning guidance only. Final sizing must come from your nameplate values and the National Electrical Code, applied by a licensed electrician.
Working on the machine side next? See three-phase output wire size or go back to the wire sizing overview.