Wire Fill for Electric Range Circuit
Electric range wire fill: standard 50A circuit uses 6 AWG copper, 40A uses 8 AWG, 4-wire NEMA 14-50 in 1-inch conduit. NEC 210.19(C) and 220.55.
Wire fill for electric range circuits is governed by NEC 210.19(C) and 220.55. The standard residential electric range uses a 50A 240V circuit with 6 AWG copper THHN in 4-wire configuration (2 hots, neutral, EGC) terminated at a NEMA 14-50 receptacle. Smaller ranges (under 12 kW) can use a 40A circuit with 8 AWG copper. Conduit sizing: 3/4-inch EMT for 40A, 1-inch EMT or PVC for 50A. Older 3-wire NEMA 10-50 installations are grandfathered but not allowed in new construction.
Load characteristics
Range loads vary by appliance:
| Range nameplate | Demand load per NEC 220.55 | Typical circuit |
|---|---|---|
| 8 kW | 8 kW × 80% = 6.4 kW (27A) | 40A |
| 10 kW | 8 kW (33A) | 40A |
| 12 kW | 8 kW (33A) | 40A or 50A |
| 14 kW | 8.8 kW (37A) | 50A |
| 16 kW | 9.6 kW (40A) | 50A |
| 20 kW commercial | 12 kW (50A) | 60A |
Most modern slide-in and free-standing electric ranges are 11-14 kW, which falls in the 50A circuit sweet spot.
NEC code references
- NEC 210.19(C) — branch-circuit conductors for ranges over 8-3/4 kW
- NEC 220.55 — household cooking appliance demand factors (Table 220.55)
- NEC 250.140 — frames of ranges and clothes dryers — must use EGC, not neutral
- NEC 422 — appliances (general)
- NEMA 14-50 — 4-wire 50A 250V receptacle standard
Conductor sizing
Use 75°C column of NEC 310.16:
| Range circuit | Copper THHN | Aluminum XHHW-2 |
|---|---|---|
| 30A (small wall oven) | 10 AWG | 8 AWG |
| 40A | 8 AWG | 6 AWG |
| 50A | 6 AWG | 4 AWG |
| 60A (pro-style range) | 6 AWG | 4 AWG |
EGC per NEC 250.122:
| Range circuit | Copper EGC |
|---|---|
| 30A | 10 AWG |
| 40A | 10 AWG |
| 50A | 10 AWG |
| 60A | 10 AWG |
Conduit sizing
4-wire range circuit (2 hots + neutral + EGC) in EMT or PVC:
| Circuit | Conductors | Total area | 3/4" EMT | 1" EMT | 1" PVC Sch 40 |
|---|---|---|---|---|---|
| 40A | 3 × 8 + 1 × 10 EGC | 0.1228 in² | 27.4% | 16.1% | 14.8% |
| 50A | 3 × 6 + 1 × 10 EGC | 0.1732 in² | 38.6% (pass) | 22.7% | 20.8% |
| 60A | 3 × 6 + 1 × 10 EGC | 0.1732 in² | 38.6% (pass) | 22.7% | 20.8% |
For a 50A range circuit, 1-inch raceway is more comfortable than 3/4-inch though 3/4" technically passes. NM-B 6/3 cable (6/3 with ground) is commonly used in residential work without conduit; through-stud runs of NM-B are not subject to fill calculations.
Special requirements
- 4-wire receptacle: NEMA 14-50 (50A) or NEMA 14-30 (30A). All new construction must use 4-wire.
- No bonding strap on appliance: When wiring a 4-wire NEMA 14-50 cordset to the range, remove the factory bonding strap between neutral and frame. The strap is for 3-wire 10-50 installations only.
- GFCI: NEC 210.8(D) requires GFCI on dwelling unit kitchen ranges starting in the 2020 NEC (and onward). Check your AHJ for adoption.
- Receptacle vs hardwired: Receptacle is most common. Hardwired drop-in cooktops use a junction box in the cabinet.
- No tap rules apply — branch circuit must run unbroken from breaker to receptacle.
Worked example — 14 kW slide-in range, NEMA 14-50 outlet
- Nameplate: 14 kW @ 240V
- Demand per Table 220.55: 8.8 kW = 36.7A
- Branch circuit: 50A 2-pole breaker
- Conductors: 6 AWG copper THHN × 3 (L1, L2, N) + 10 AWG copper EGC
- Raceway: 1" EMT from panel to range outlet, 25 ft run.
- Fill check: 3 × 0.0507 + 0.0211 = 0.1732 in² in 1" EMT (40% limit = 0.346) = 22.7%, pass.
- Receptacle: NEMA 14-50R, 50A 250V, single-receptacle box (NEC 210.21(B)(1)).
If using NM-B cable: 6/3 with ground NM-B is rated for 55A at 60°C (NEC 334.80), so it works for the 50A circuit. No conduit needed for runs through framing.
Quick reference
| Range size | Demand | Breaker | Copper wire | EGC | Conduit |
|---|---|---|---|---|---|
| Wall oven only (4-5 kW) | 5 kW | 30A | 10 AWG × 3 | 10 AWG | 3/4" EMT |
| 8 kW range | 6.4 kW | 40A | 8 AWG × 3 | 10 AWG | 3/4" EMT |
| 12 kW range | 8 kW | 40A or 50A | 8 AWG / 6 AWG × 3 | 10 AWG | 3/4" EMT / 1" |
| 14 kW range | 8.8 kW | 50A | 6 AWG × 3 | 10 AWG | 1" EMT |
| 16 kW range | 9.6 kW | 50A | 6 AWG × 3 | 10 AWG | 1" EMT |
| 20 kW pro range | 12 kW | 60A | 6 AWG × 3 | 10 AWG | 1" EMT |
Related
FAQ
This page's figures are transcribed from NEC 2023 (NFPA 70) Chapter 9, Tables 1, 4 and 5, and checked by a version-controlled automated test suite — they are not signed off by a licensed professional. WireFillChart is an independent reference, not affiliated with or endorsed by NFPA. Always verify against the code edition adopted by your local authority having jurisdiction (AHJ).