Wiring an outlet for an electric stove isn't the same as wiring standard outlets, because along with the water heater, furnace and central air system, the stove is a high-demand appliance that runs on 240-volt power. There are specific electric stove wiring requirements you have to follow.
For one, the stove must be on a dedicated circuit. Appliances on 120-volt circuits require only a single hot wire. But the circuit for electric stoves requires two hot wires: a neutral and a ground. Each hot wire needs its own breaker, and the breakers must be stacked together and joined so that, if one trips, the other will also trip.
The size requirements for the cable and the breaker depend on the stove. They are the same whether you install an outlet for a plug or you hardwire the stove directly to the circuit. You don't need to consult the electric stove wiring diagram, generally, because if the stove doesn't have a cord, you will only need to know the location of the terminal box, and that's easy to find.
Oven Breaker Size Depends on Current Draw
Most electric ranges draw from 30 to 50 amps of current, depending on the size and the features. You can determine the current draw for your stove by checking the label on the back, which is next to the power terminals or the place where the cord exits the appliance. The circuit breaker current rating must match the rating on this label.
A standard kitchen range with four burners and an oven could draw 30, 40 or 50 amps. But a large commercial unit, or one with features like a convection oven or quick-heat burners, draw 50 to 60 amps. When working at their maximum capacity, electric stoves consume 7 to 14 kilowatts of power, so they are not only energy-intensive appliances, but they are also expensive to operate.
You don't want to underestimate the oven breaker size, or it will trip whenever you turn the stove on. But you don't want to oversize it, either. If the breaker current rating is higher than that of the stove, a surge malfunction could overheat something in the stove and cause a fire without the breaker shutting off to prevent it.
Range Wire Size Depends on Breaker Size
The size of the electrical cable is measured by its American Wire Gauge (AWG), a system where the gauge number decreases with increasing wire diameter. When it comes to 120-volt circuits, the most common range wire sizes are 14 and 12 AWG. Because they draw more current, 240-volt appliances require a minimum wire size of 10 AWG.
As a general rule of thumb, you should size the wire according to the following rules: 10 AWG for up to 30 amps, 8 AWG for 40 to 50 amps and 6 AWF for more than 50 amps.
This is a rule of thumb because wire size also depends on the length of the wire. Voltage drop can affect performance in undersized wires that are very long. This only becomes a factor when the length exceeds 100 feet, which is unlikely in residential wiring. But if in doubt, upgrade to the next heavier gauge.
Electric Stove Outlet Requirement
If you want to install an outlet to plug in the stove, you must choose the outlet configuration that corresponds to the current draw of the appliance. Circuit grounding is required, so all 240-volt receptacles have four slots, but 30-amp receptacles, such as the NEMA 14-30, won't accept a plug from a 40- or 50-amp appliance. When in doubt, choose the receptacle that matches the plug on your stove.
Chris Deziel is a contractor, builder and general fix-it pro who has been active in the construction trades for 40 years. He has degrees in science and humanities and years of teaching experience. An avid craftsman and musician, Deziel began writing on home improvement topics in 2010. He worked as an expert consultant with eHow Now and Pro Referral -- a Home Depot site. A DIYer by nature, Deziel regularly shares tips and tricks for a better home and garden at Hunker.com.