Hardwiring an Appliance
Most 120-volt appliances simply plug into standard receptacles. Some 240-volt appliances plug into special 240-volt receptacles. Other appliances -- those that use 240 volts and are stationary -- are hardwired, meaning that cable attaches directly to the circuit. Garbage disposers and dishwashers may be either plugged in or hardwired.
Shut off power to the circuit before installing any appliance. These are general directions for some typical installations. Consult the manufacturer's instructions before wiring -- wire colors and cable connections may vary.
If you shut off a circuit breaker to work on a 240-volt appliance, another person may mistakenly flip the breaker on while you are doing the wiring, creating a very dangerous situation. That is why building codes may require a hardwired appliance to have a disconnect -- basically an on/off switch. The disconnect must be positioned within sight of the appliance. An alternative is to install a circuit breaker with a lockout feature, which allows you to lock the breaker shut to prevent an accident.
About 1 hour to make most connections once cable has been run
Screwdriver, flashlight, strippers, lineman's pliers, long-nose pliers
Stripping, splicing, and connecting wires to terminals
See that the new appliance does not overload the circuit. Remove the old appliance or run cable for a new appliance.
Appliance, wire nuts, electrician's tape
Under the sink, a split and switched receptacle can provide an always-hot plug for a hot-water dispenser and a switched plug for the garbage disposer. Some codes may require the disposer to be hardwired, in which case a separate, switched junction box is needed (shown).Dishwasher
Codes may require a dishwasher to be on a dedicated circuit. Some models plug into receptacles, but most are hardwired. Provide a cable that can reach to the front of the dishwasher. Slide the dishwasher into the space and make the plumbing connections. Open the dishwasher's junction box and splice wires to the dishwasher's leads. Replace the junction box cover.Electric water heater
A water heater requires a dedicated 240-volt circuit. Check the unit's amperage rating and make sure the circuit can handle at least 120 percent of the rating. For most homes, a 30-amp circuit with 10/2 cable is sufficient. Because of the heat the unit generates, use Greenfield or armored cable rather than NM cable. Remove the cover plate, splice the wires (note that a neutral is not required), and replace the cover plate.Garbage disposer
Garbage disposers are sold without cords so they can be wired directly to a junction box (hardwiring) or to an appliance cord with a plug. Install armored cable (shown), or buy a cord that can handle the disposer's amperage rating. Splice the wires to the disposer first. Install it under the sink. Then hardwire or plug the disposer into a switched receptacle. A disposer should not be on a light circuit, or lights will dim when it starts.Electric cooktop
An electric cooktop or wall-mounted oven requires a 120/240-volt circuit -- 120 volts to power lights and timer, 240 volts for the heating elements. A cooktop and an oven can be wired to the same circuit. Run cable to a nearby junction box. An electric oven or cooktop usually has a short length of armored cable, called a whip. Clamp the whip to the junction box; make the splices. Make sure the wire and breaker are big enough for both.
- Electrical Safety: Steps for Developing Safe Habits
- Electrical Project Planning & Prep
- Your Electrical System
- Basic Electrical Wiring Techniques
- Electrical Repair, Problem Solving & Maintenance
- Switches & Receptacles: How to Replace or Upgrade a Switch or Receptacle
- Lights & Fans: Mounting and Wiring Light Fixtures & Fans
- Planning New Electrical Service
- Cable & Boxes: How to Install Electrical Cable & Boxes
- New Fixtures: How to Install a New Electrical Fixture
- Fans & Heaters: How to Install a Fan or Home Heater
- Household Voice, Data & Security: How to Install Your System
- Outdoor Wiring: How to Install & Plan Outdoor Wiring Projects