Today’s electric ranges have specific power requirements. An electric range is a 240-volt appliance that usually plugs into a special range 4-pronged receptacle. While newer appliances have 4-prong cords to fit 4-slot outlets, many find stoves still manufactured before 1996 feature 3 prongs for the 3-slot receptacles. If you’ve purchased a new range and a cord wasn’t included, or you’ve moved and need to adapt your range to a four-slot outlet, you’ll need to install a 4 prong range cord.
What is a Four-Prong Cord?
The National Fire Protection Association updated the National Electrical Code (NEC) book in 1996. This update changed wiring requirements for electric ranges and clothes dryers, increasing the need from three wires to four wires. Over the next few years, most cities issued new laws for new installations, while most local codes and the NEC permit existing installations to still use three-wire configurations.
A four-wire cord has two “hot” wires, in addition to a neutral wire and a separate ground wire that three-wire cords lack. Three-wire cords use the neutral wire as a ground path. While this usually doesn’t cause a problem, an electrical short and circuit breaker failure can lead to a shock. Four-wire cords are therefore safer to use.
Preparing for Installation
In order to install a 4 prong range cord, you’ll need to connect the ground wire to a ground screw on the appliance. Any straps or wires between the ground screw and neutral terminal will have to be removed first, to separate the two, unless you have a new range that is set up to meet the latest standards. Units with a four-wire configuration separate the ground from the neutral, so there’s no strap or wire to deal with.
To properly install a four-wire cord if needed, you’ll need a Phillips screwdriver or nut driver, properly sized strain-relief clamp, and possibly tongue-and-groove pliers. Most importantly, you’ll need a 40- or 50-amp UL-listed electric range cord. Cords are available at home improvement stores in a standard four-foot length.
Installing a 4 Prong Range Cord
Follow these steps to safely and successfully install a four-prong range cord:
1. Turn Off the Circuit
Find the circuit for the range’s outlet in the breaker panel and switch it off. While your range won’t be plugged in when installing the cord, this is an added safety measure.
2. Remove the Cover Plate
There is a metal cover plate (or shroud) on the range’s back panel. Remove it to access the wiring terminal block, by removing its screws or bolts. You will need the plate and fasteners later, so store them in a secure location.
3. Disconnect the Old Cord
If the old three-wire cord is still attached, loosen the three screws or nuts securing the cord wires and pull the end of each wire from the terminal inside the wire splice box. If there is a ground wire, remove it the same way.
- Also, remove the strain relief fitting’s screws and separate the two halves. You will now be able to pull the cord out through the hole in the back panel. Do not use the same strain relief for the four-prong cord.
4. Isolate the Ground Connection:
If the ground is connected to the neutral cord terminal by a metal strap, loosen the ground screw/neutral terminal screw, remove the metal strap, or leave it in place and rotate it away from the neutral terminal. Also look for a small wire in the back of the range with white insulation. If the white ground wire is connected to the ground, removed it by loosening the ground screw and moving the wire to the neutral terminal (both white wires will be connected here).
5. Connect the New Cord:
For the final installation of the four-prong cord:
- Run the end of the cord through the hole behind the range.
- Connect the ring of the white cord wire onto the center terminal, and tighten the terminal screw or nut.
- In the same way, connect the black cord wire to the left or right terminal.
- Secure the red cord wire to the remaining terminal.
- Attach the green ground wire to the ground screw.
- Ensure all screws are fit tightly and securely.
6. Complete the Installation
Using the strain relief fitting for the four-prong cord, insert its upper and lower halves into the hole the cord passes through. Both halves should rest on the top and bottom of the cord. Using pliers, squeeze the two halves together and tighten the screws little by little, alternating sides during the process. This ensures the cord is squeezed firmly and evenly. Now you can reinstall the cover plate/shroud, plug the cord into the range outlet, and turn the power on to test the appliance.
Need Assistance? Contact Express Electrical Services
Our trained, licensed electrical technicians can help you with any wiring work. We’re equipped with the tools and equipment to get the job done correctly and safely. To request help installing a four-prong cord for your range, submit your request online or call 323-727-7799 today.