How to Wire a Nema 6-50P Plug

Nema 6-50P plugs connect appliances to 250-volt 50-amp electrical circuits, and they use cable with 8-gauge wire or larger. The face of the plug has two straight prongs, one of which is roughly half the size of the other, with the larger prong on the right, and a semi-circle-shaped ground prong positioned above and between the other two. The plug usually has a circular or square face roughly two inches across, and it is used on appliances such as electric welders.

  1. Cut off two inches of outer sheathing from the end of the power cord using a utility knife. Remove 1/2 an inch of plastic coating from the ends of the two wires inside, using wire strippers or the utility knife. The cable has a third bare ground wire, or it may be coated with green plastic.

  2. Open the cover on the back of the plug by taking out its screws. Loosen each of the terminal screws inside the plug casing. Loosen the screws holding the clamps together on the plug's handle. Slip the wires between the clamps and push them through.

  3. Push the end of the bare ground wire into the ground terminal and tighten its green screw to the wire. Push the black wire into the terminal connected to the small prong. Tighten the terminal screw to the wire. Insert the remaining wire into the other terminal connected to the larger prong. Tighten its screw to the wire.

  4. Push the cover in position onto the back of the plug and install the screws. Tighten the clamp screws.

About the Author

Steve Sloane started working as a freelance writer in 2007. He has written articles for various websites, using more than a decade of DIY experience to cover mostly construction-related topics. He also writes movie reviews for Inland SoCal. Sloane holds a Bachelor of Arts in creative writing and film theory from the University of California, Riverside.