How to Wire a 120/240 Volt Receptacle

cord plugged into a white outlet
  • 2-5 hours
  • Intermediate
  • 0-200
What You'll Need
120/240 volt receptacle outlet
Wire cutters
Wire strippers
Dual pole 50 amp circuit breaker
Electrical wiring
Conduit (unless ROMEX or NM shielded cable is being used)
Multimeter or test light

If you need to replace an old 240 volt receptacle, you might want to consider replacing the old outlet with a 120/240 volt unit. This type of receptacle allows you to plug in 120 and 240 volt devices. The receptacle has a special prong insert layout that allows it to work with most common plug types and is usually powered by two individual circuits. Wiring a new 120/240 volt receptacle is easier than you think, and this simple how-to guide will show you everything you need to know.

Step 1 - Turn Off the Power

Turn off the power for the old 240 volt receptacle at the main breaker box in your home. Then, use a multimeter or test light to test the old outlet to make sure power no longer flows to it.

Step 2 - Disconnect and Remove Old Outlet

Disconnect and remove the old 240 volt receptacle by removing the retaining screw, removing the mounting screws, and disconnecting the wiring. You will usually need to only loosen the terminal screws on the back of the receptacle to remove the wiring.

Step 3 - Run New Wiring

circuit box

Run a new piece of 12 or 14 gauge electrical wire through the conduit that was used for the old 240 volt receptacle. If you have Romex or NM shielded wire cable installed, you'll simply need to run a new piece of that type of cable. Make sure the cable runs all the way from the old receptacle to the breaker box.

Step 4 - Connect at Breaker Box

Install (or have a licensed electrician install for you) the dual pole 50 amp circuit breaker into your main breaker box. This will provide the power for the two circuits needed to run the 120/240 volt receptacle.

Step 5 - Connect Positive Power Leads

Loose wires for an outlet

Connect the positive (or hot) power wires to the two brass colored screw terminals on the new 120/240 volt receptacle. If the bare wire copper ends on the cable are damaged or frayed, cut them with a pair of wire cutters and strip the ends of the wire again before screwing them down on the terminal.

Step 6 - Install Neutral Lead

Connect the white (or neutral) power wire to the silver colored screw terminal on the new receptacle. Again, make sure the bare copper wire on the electrical wire is not frayed or damaged and it does not protrude outside the screw terminal too much.

Step 7 - Connect Grounding Wire

Use a screwdriver to connect the grounding wire to the screw terminal with a green painted top. This is the grounding wire which is used to help protect devices or appliances that are plugged into the receptacle.

Step 8 - Install Receptacle

Take the new receptacle and set it into the outlet box. Then, use the mounting screws to install it inside the box. Finally, place the cover plate of the receptacle and insert and tighten the retaining screw.