How to connect a 120/240 volt receptacle

If you need to replace an old 240 volt receptacle, you may replace 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 plug insertion design that allows it to work with the most common types of plugs and is 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.

What will you need?

  • 120/240 volt receptacle outlet

  • Wire cutters

  • Wire stripper

  • Screwdrivers

  • 50 amp bipolar circuit breaker

  • Electrical wiring

  • Conduit (unless ROMEX or NM shielded cable is used)

  • Multimeter or test light

Step 1: turn off the power

Disconnect power from the old 240 volt receptacle in your home’s main breaker box. 

Next, use a multimeter or test light to test the old outlet to make sure power is no longer flowing into it.

Step 2 – Disconnect and remove the old plug

Disconnect and remove the old 240 volt receptacle by removing the keeping screw, removing the mounting screws, and disconnecting the wiring.

 Typically, you will only need to loosen the terminal screws on the back of the receptacle to remove the wiring.

Step 3: run a new wiring

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 a Romex or NM shielded wire cable installed, you will simply need to run a new piece of that type of cable.

 Make sure the cable runs from the old receptacle to the switch box.

Step 4: plug into the switch box

Install (or have a licensed electrician install) the 50 amp double pole breaker in your main breaker box. 

This will provide the power for the two circuits needed to run the 120/240 volt receptacle.

Step 5 – Connect the positive power cables

Connect the positive (or hot) power leads to the two brass colored screw terminals on the new 120/240 volt receptacle. 

If the bare copper ends of the wire are damaged or frayed, cut them off with a pair of wire cutters and re-strip the wire ends before screwing them into the terminal.

Step 6 – Install the neutral wire

Connect the white (or neutral) power wire to the silver-colored screw terminal on the new receptacle. 

Again, make sure that the bare copper wire on the electrical wire is not frayed or damaged and that it does not protrude too far from the screw terminal.

Step 7 – Connect the ground wire

Use a screwdriver to connect the ground wire to the screw terminal with a green painted top.

 This is the grounding wire that is used to help protect devices or appliances that are plugged into the receptacle.

Step 8 – Install the receptacle

Take the new receptacle and place it in the outlet box. Then use the mounting screws to install it inside the box. 

Finally, replace the socket cover and insert and tighten the keeping screw.

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