Electrical Voltage Drop Calculator (Single & Three-Phase)
Check voltage lost over long wire runs and automatically find the minimum Copper or Aluminum wire gauge to stay under the NEC 3% branch limit.
3. Voltage Drop Calculator (NEC 3% Branch / 5% Feeder Rule)
Bulk Wire & Voltage Testing Gear
NEC Quick-Lookup Charts (60+ Field Reference Pages)
Select any wire size, conduit trade size, or circuit breaker amperage below for instant NEC Chapter 9 and Table 310.16 calculations:
Wire Size by Breaker Amps
- 15 Amp Wire Size: 14 AWG Copper / 12 AWG Aluminum (Lighting circuits)
- 20 Amp Wire Size: 12 AWG Copper / 10 AWG Aluminum (Kitchen)
- 25 Amp Wire Size: 10 AWG Copper / 8 AWG Aluminum (Air conditioning condensers)
- 30 Amp Wire Size: 10 AWG Copper / 8 AWG Aluminum (Electric clothes dryers)
- 35 Amp Wire Size: 8 AWG Copper / 6 AWG Aluminum (Heat pumps)
- 40 Amp Wire Size: 8 AWG Copper / 6 AWG Aluminum (Electric ranges)
- 45 Amp Wire Size: 8 AWG Copper / 6 AWG Aluminum (Instantaneous water heaters & commercial kitchen equipment)
- 50 Amp Wire Size: 6 AWG Copper / 4 AWG Aluminum (40A Level 2 EV chargers (NEMA 14-50))
- 60 Amp Wire Size: 6 AWG Copper / 4 AWG Aluminum (48A hardwired EV chargers (Tesla Wall Connector) & 60A garage subpanels)
- 70 Amp Wire Size: 4 AWG Copper / 2 AWG Aluminum (Subpanels)
- 80 Amp Wire Size: 4 AWG Copper / 2 AWG Aluminum (64A Ford Charge Station Pro EV chargers & heavy workshop subpanels)
- 100 Amp Wire Size: 3 AWG Copper / 1 AWG Aluminum (100A detached garage/workshop subpanels & small residential services)
- 125 Amp Wire Size: 1 AWG Copper / 2/0 AWG Aluminum (125A subpanels)
- 150 Amp Wire Size: 1/0 AWG Copper / 3/0 AWG Aluminum (150A residential main service & commercial distribution panels)
- 200 Amp Wire Size: 3/0 AWG Copper / 250 kcmil Aluminum (200A main residential service entrance & commercial feeder panels)
EMT Conduit Fill by Wire Gauge
- How many 14 AWG wires in 1/2" EMT Conduit? (12 THHN max)
- How many 12 AWG wires in 1/2" EMT Conduit? (9 THHN max)
- How many 10 AWG wires in 1/2" EMT Conduit? (5 THHN max)
- How many 8 AWG wires in 1/2" EMT Conduit? (3 THHN max)
- How many 6 AWG wires in 1/2" EMT Conduit? (2 THHN max)
- How many 14 AWG wires in 3/4" EMT Conduit? (21 THHN max)
- How many 12 AWG wires in 3/4" EMT Conduit? (16 THHN max)
- How many 10 AWG wires in 3/4" EMT Conduit? (10 THHN max)
- How many 8 AWG wires in 3/4" EMT Conduit? (5 THHN max)
- How many 6 AWG wires in 3/4" EMT Conduit? (4 THHN max)
- How many 4 AWG wires in 3/4" EMT Conduit? (2 THHN max)
- How many 2 AWG wires in 3/4" EMT Conduit? (1 THHN max)
- How many 12 AWG wires in 1" EMT Conduit? (25 THHN max)
- How many 10 AWG wires in 1" EMT Conduit? (16 THHN max)
- How many 8 AWG wires in 1" EMT Conduit? (9 THHN max)
- How many 6 AWG wires in 1" EMT Conduit? (6 THHN max)
- How many 4 AWG wires in 1" EMT Conduit? (4 THHN max)
- How many 2 AWG wires in 1" EMT Conduit? (2 THHN max)
- How many 1/0 AWG wires in 1" EMT Conduit? (1 THHN max)
- How many 10 AWG wires in 1-1/4" EMT Conduit? (28 THHN max)
- How many 8 AWG wires in 1-1/4" EMT Conduit? (16 THHN max)
- How many 6 AWG wires in 1-1/4" EMT Conduit? (11 THHN max)
- How many 4 AWG wires in 1-1/4" EMT Conduit? (7 THHN max)
- How many 2 AWG wires in 1-1/4" EMT Conduit? (5 THHN max)
- How many 1/0 AWG wires in 1-1/4" EMT Conduit? (3 THHN max)
- How many 2/0 AWG wires in 1-1/4" EMT Conduit? (2 THHN max)
- How many 3/0 AWG wires in 1-1/4" EMT Conduit? (2 THHN max)
- How many 6 AWG wires in 1-1/2" EMT Conduit? (16 THHN max)
- How many 4 AWG wires in 1-1/2" EMT Conduit? (9 THHN max)
- How many 2 AWG wires in 1-1/2" EMT Conduit? (7 THHN max)
- How many 1/0 AWG wires in 1-1/2" EMT Conduit? (4 THHN max)
- How many 2/0 AWG wires in 1-1/2" EMT Conduit? (3 THHN max)
- How many 3/0 AWG wires in 1-1/2" EMT Conduit? (3 THHN max)
- How many 6 AWG wires in 2" EMT Conduit? (26 THHN max)
- How many 4 AWG wires in 2" EMT Conduit? (16 THHN max)
- How many 2 AWG wires in 2" EMT Conduit? (11 THHN max)
- How many 1/0 AWG wires in 2" EMT Conduit? (7 THHN max)
- How many 2/0 AWG wires in 2" EMT Conduit? (6 THHN max)
- How many 3/0 AWG wires in 2" EMT Conduit? (5 THHN max)
PVC Sch 40 & 80 Conduit Fill
- How many 14 AWG wires in 1/2" PVC Schedule 40 Conduit? (11 THHN max)
- How many 12 AWG wires in 1/2" PVC Schedule 40 Conduit? (8 THHN max)
- How many 10 AWG wires in 1/2" PVC Schedule 40 Conduit? (5 THHN max)
- How many 8 AWG wires in 1/2" PVC Schedule 40 Conduit? (3 THHN max)
- How many 6 AWG wires in 1/2" PVC Schedule 40 Conduit? (2 THHN max)
- How many 14 AWG wires in 3/4" PVC Schedule 40 Conduit? (20 THHN max)
- How many 12 AWG wires in 3/4" PVC Schedule 40 Conduit? (15 THHN max)
- How many 10 AWG wires in 3/4" PVC Schedule 40 Conduit? (9 THHN max)
- How many 8 AWG wires in 3/4" PVC Schedule 40 Conduit? (5 THHN max)
- How many 6 AWG wires in 3/4" PVC Schedule 40 Conduit? (4 THHN max)
- How many 4 AWG wires in 3/4" PVC Schedule 40 Conduit? (2 THHN max)
- How many 12 AWG wires in 1" PVC Schedule 40 Conduit? (25 THHN max)
- How many 10 AWG wires in 1" PVC Schedule 40 Conduit? (15 THHN max)
- How many 8 AWG wires in 1" PVC Schedule 40 Conduit? (9 THHN max)
- How many 6 AWG wires in 1" PVC Schedule 40 Conduit? (6 THHN max)
- How many 4 AWG wires in 1" PVC Schedule 40 Conduit? (4 THHN max)
- How many 2 AWG wires in 1" PVC Schedule 40 Conduit? (2 THHN max)
- How many 8 AWG wires in 1-1/4" PVC Schedule 40 Conduit? (15 THHN max)
- How many 6 AWG wires in 1-1/4" PVC Schedule 40 Conduit? (11 THHN max)
- How many 4 AWG wires in 1-1/4" PVC Schedule 40 Conduit? (7 THHN max)
- How many 2 AWG wires in 1-1/4" PVC Schedule 40 Conduit? (5 THHN max)
- How many 1/0 AWG wires in 1-1/4" PVC Schedule 40 Conduit? (3 THHN max)
- How many 2/0 AWG wires in 1-1/4" PVC Schedule 40 Conduit? (2 THHN max)
- How many 4 AWG wires in 2" PVC Schedule 40 Conduit? (15 THHN max)
- How many 2 AWG wires in 2" PVC Schedule 40 Conduit? (11 THHN max)
- How many 1/0 AWG wires in 2" PVC Schedule 40 Conduit? (7 THHN max)
- How many 2/0 AWG wires in 2" PVC Schedule 40 Conduit? (5 THHN max)
- How many 3/0 AWG wires in 2" PVC Schedule 40 Conduit? (4 THHN max)
- How many 14 AWG wires in 3/4" PVC Schedule 80 Conduit? (16 THHN max)
- How many 12 AWG wires in 3/4" PVC Schedule 80 Conduit? (12 THHN max)
- How many 10 AWG wires in 3/4" PVC Schedule 80 Conduit? (7 THHN max)
- How many 8 AWG wires in 3/4" PVC Schedule 80 Conduit? (4 THHN max)
- How many 6 AWG wires in 3/4" PVC Schedule 80 Conduit? (3 THHN max)
- How many 12 AWG wires in 1" PVC Schedule 80 Conduit? (20 THHN max)
- How many 10 AWG wires in 1" PVC Schedule 80 Conduit? (13 THHN max)
- How many 8 AWG wires in 1" PVC Schedule 80 Conduit? (7 THHN max)
- How many 6 AWG wires in 1" PVC Schedule 80 Conduit? (5 THHN max)
- How many 4 AWG wires in 1" PVC Schedule 80 Conduit? (3 THHN max)