An electric range is a freestanding unit containing an oven and a cooktop. This 240-volt appliance typically plugs into a range receptacle that is fed by a 40-amp or 50-amp circuit dedicated to the range only. Older range cords (prior to 1996), had 3-prong cords to fit 3-slot receptacles, while newer ranges have 4-prongs to fit 4-slot outlets. You can use either type of cord, depending on the type of receptacle you have.
The installation steps for 3-prong and 4-prong cords are similar but include some key differences. Ranges wired for 3-prong cords may have only three wiring terminals for the cord: one neutral and two "hot" connections. If there is a ground screw, it should be electrically connected to the neutral terminal with a metal strap or wire. This connection grounds the body of the appliance through the neutral cord wire.
Ranges wired for 4-prong cords have four terminals: one neutral, two hots, and a ground. The ground wire connects to the ground screw on the appliance. If the range has a strap or wire between the ground screw and the neutral terminal, you must remove the strap or wire to separate the ground from the neutral. If the range is new, it should be set up for a 4-prong cord; this follows a National Electrical Code requirement that was initiated in 1996.
Consult your owner's manual or the range manufacturer for specific wiring requirements. The cord you use must have the same amperage rating as the range circuit.
Equipment / Tools
- Phillips screwdriver or nut driver
- Tongue-and-groove pliers (optional)
- 40- or 50-amp, UL-listed electric range cord
- Strain-relief clamp sized for the range cord
Remove the Wire Connection Cover Plate
Locate the removable metal cover plate or shroud on the back panel of the range. This covers the cavity that houses the wiring terminal block of the range. There may be a hole about 1 inch in diameter in or near the cover; this is for the cord to pass through. Remove the screws or bolts securing the cover, using a screwdriver or nut driver, and remove the cover from the range.
Alter the Ground Connection, if Necessary
Note the wiring configuration on the terminal block. There are three terminals in a line: the center terminal is the neutral and usually has a white wire; the left terminal is hot and may have a red or black wire; the right terminal also is hot and may have a black or red wire. There may or may not be a ground screw near the terminal block—if present, this will be driven into the metal case of the appliance.
If necessary, alter the ground-to-neutral connection as needed, depending on the type of cord you are installing:
- If there is no connecting strap or wire on the ground screw, the range is ready for the 4-prong cord. No alteration is necessary.
- If there is a ground screw and it is connected to the neutral (center) terminal with a metal strap, remove the strap from the neutral terminal on the terminal block (you can remove the strap entirely or keep it attached under the ground screw). If there is a small white wire connected to the ground screw, remove it from the ground and fit it onto the neutral terminal on the block. This is an internal neutral connection; you will connect it to the neutral terminal along with the neutral cord wire just to keep it safely secured (it won't serve a purpose).
- If there is no ground screw, no alteration is necessary.
- If there is a ground screw and it is connected to the neutral (center) terminal with a metal strap or small, white wire, leave the strap or wire in place. No alteration is necessary. The wire makes an internal connection to the neutral.
- If there is a ground screw and it is not connected to the neutral with a strap or wire, follow the manufacturer's wiring diagram to make the proper ground-to-neutral connection.
Note: The next two slides are specific to 4-prong cords and 3-prong cords, respectively.
Connect a 4-Prong Cord (4-Prong Only)
Insert the end of the 4-prong cord through the hole in the back panel of the range. Loosen or remove the screw on the center neutral terminal and attach the white cord wire to the terminal, tightening it down under the screw terminal. Attach the black cord wire to the hot terminal with the black wire. Attach the red cord wire to the hot terminal with the red wire. Attach the green cord wire to the ground screw on the range body. Tighten all of the screws firmly.
The two hot terminals are interchangeable, and each hot cord wire can connect to either hot terminal. The color coding of the hot terminals is not important. However, each terminal must have only one wire connected to it.
Connect a 3-Prong Cord (3-Prong Only)
Insert the end of the 3-prong cord through the hole in the back panel of the range and position the cord so its flat side is facing you. Connect the center cord wire to the center (neutral) terminal, and tighten down the terminal screw. Connect the left cord wire to the left hot terminal, and connect the right cord wire to the right hot terminal. The hot terminals and cord wires are interchangeable. Tighten all of the screws firmly.
Install the Strain-Relief Clamp
Install a strain-relief clamp to secure the cord to the back of the range. Its purpose is to grip the cord to protect the wire connection and prevent damage to the cord. This is typically a two-piece clamp that requires assembly.
Remove the screws holding the clamp halves together. Insert the tab of the top half into the cord hole and fit the center of the clamp piece over the top of the cord. Repeat with the bottom half on the underside of the cord. Reinstall the screws and tighten the clamp snugly onto the cord. You may want to squeeze the two halves together gently with tongue-and-groove pliers while installing the screws. Do not overtighten the clamp, which can damage the cord insulation and possibly expose a wire.
Reinstall the Cover Plate
Reinstall the cover plate or shroud over the wiring cavity to complete the installation. Make sure all controls on the range are OFF. Plug the cord into the range outlet, and test the range functions to confirm proper operation.