Step-by-step: wiring an electric range

Load calculation and circuit sizing

Most residential ranges land between 8 kW and 16 kW nameplate. Per NEC 220.55 and Table 220.55, a single household range over 8¾ kW uses Column C, starting at 8 kW demand and adding 5% per kW above 12 kW. A 12 kW range calculates at 8 kW, which pulls 33.3 A at 240 V. That is why the 40 A circuit became the default, not because the nameplate says 40.

Check the nameplate before you pull wire. A 16.5 kW commercial-style range will push you to a 50 A circuit with #6 copper. Anything under 8¾ kW and you follow the nameplate directly, no demand factor applied.

• Under 8¾ kW: size to nameplate, typically 30 A
• 8¾ kW to 12 kW: 8 kW demand, 40 A circuit, #8 Cu
• 12.1 kW to 13 kW: 8.4 kW demand, still 40 A in most cases
• Over 16 kW: recalculate per Column C, usually 50 A with #6 Cu

Conductor, conduit, and receptacle selection

For a 40 A range circuit using NM-B, #8/3 with ground is standard per 334.80 and the 60°C column of Table 310.16. In conduit with THHN, #8 copper at 75°C gets you 50 A of ampacity, but the terminations on most ranges and breakers are 75°C rated, so verify before you upsize. Aluminum is legal but uncommon for ranges, #6 AL if you go that route.

The receptacle is a NEMA 14-50R for 50 A circuits or 14-30R for 30 A. Four-wire is required on all new installs per 250.140. The three-wire 10-30 frame-bonded setup is only permitted on existing branch circuits, never on a new feed, even if the homeowner swears the old one worked fine for 40 years.

Check the whip that came with the range. Factory pigtails are often rated for the appliance but not the circuit you are landing on. If the pigtail is 40 A and the circuit is 50 A, you need a different pigtail or a different breaker.

Grounding and bonding at the appliance

New installations require a four-wire connection: two hots, a neutral, and an equipment grounding conductor. The bonding strap between the neutral terminal and the frame must be removed. This is the single most common callback on range swaps, the installer forgets the strap and the neutral carries fault current through the frame to ground.

NEC 250.140 is explicit. Existing 3-wire branch circuits may continue to serve ranges and dryers under the exception, but any new circuit, any service change that extends the circuit, or any relocation triggers the 4-wire requirement. Document it if you are replacing a range on legacy wiring and leaving the 3-wire in place.

Terminations and mechanical work

Range terminals are usually lug-style with a 5/16 or 3/8 hex. Torque matters. Most manufacturers spec 35 to 50 in-lb for #8 and 75 to 110 in-lb for #6. Check the label inside the terminal cover, then use a calibrated torque screwdriver or wrench. NEC 110.14(D) now requires torqued terminations to be torqued to manufacturer spec, and inspectors are calling it out.

Strip length matters as much as torque. Over-strip and you expose copper past the lug; under-strip and you are clamping insulation. Most range lugs want 3/4 inch of bare conductor. Dress the conductors so the strain relief actually grips the jacket, not the individual conductors.

1. De-energize and verify with a known-good meter
2. Install the strain relief in the range knockout before landing conductors
3. Remove the neutral-to-frame bonding strap on 4-wire installs
4. Land hots on L1 and L2, neutral on the center lug, ground on the green screw or case lug
5. Torque to spec, tug-test each conductor
6. Close the terminal cover, verify the strain relief is tight on the cable jacket

GFCI, AFCI, and kitchen rules

As of the 2023 NEC, 210.8(A)(6) requires GFCI protection for all 125V through 250V receptacles rated 50 A or less in dwelling unit kitchens. That captures the range receptacle. Hard-wired ranges are not covered by 210.8(A) since there is no receptacle, but some AHJs still require it, check local amendments.

AFCI is not required for ranges per 210.12, which carves out kitchens for AFCI with specific exceptions. GFCI breakers for 40 A and 50 A 240 V loads are available from all major manufacturers now, but nuisance tripping on older ranges with leaky heating elements is real. If a GFCI breaker trips immediately on a new install, meg the elements before blaming the breaker.

The 2023 GFCI expansion caught a lot of people off guard. If you are working in a jurisdiction still on 2020 NEC, the range receptacle does not need GFCI. Confirm the adopted code cycle before you quote the job.

Commissioning and final checks

Before energizing, verify continuity from the ground pin at the receptacle to the range frame, and confirm the neutral is isolated from the frame. Measure L1 to L2, L1 to N, and L2 to N at the receptacle. You should see 240 V and 120 V respectively, within 3% of nominal.

Run every burner and the oven through a heat cycle. Watch the breaker for nuisance trips in the first 15 minutes, that is when a miswired GFCI or a pinched conductor will show up. Leveling feet and anti-tip brackets are code (most jurisdictions reference the manufacturer install instructions via 110.3(B)), so do not skip them.