How to Wire a NEMA 6-50 Plug

A NEMA 6-50 plug has two straight hot prongs, running parallel to each other, and a horseshoe-shaped ground prong. The hot prongs on the 6-50 have different widths, with the large prong on the right. A NEMA 6-50 plug connects to a 250-volt 50-amp electrical circuit. A 50-amp electrical circuit needs 8-gauge or larger wires. The NEMA 6-50's round face measures 2-1/8 inches across, and it mounts in a standard wall-mount electrical outlet box. Some appliances, like electric welders with a 3 horsepower rating, connect to its power source with a NEMA 6-50.

Things You'll Need

  • Wire strippers

  • Utility knife

  • Slotted screwdriver

Step 1

Remove 3/8 inch of the insulation of the wires entering the NEMA 6-50 plug with either wire strippers or a utility knife. Often wire strippers will not work on the large braided wire that usually feeds a NEMA 6-50 plug.

Step 2

Loosen the NEMA 6-50 plug's wire terminal screws with a slotted screwdriver. Do not remove the screws.

Step 3

Insert the ground wire into the NEMA 6-50 plug's ground terminal. The 6-50's ground terminal has a green screw. If the wire set has a black, red and white wire, use the white wire as ground. Otherwise, the wire set's wire without insulation or the wire with green insulation acts as ground.

Step 4

Insert the stripped end of the black wire into the NEMA 6-50 plug's left-side wire terminal -- the terminal that connects to the small prong. Tighten the terminal screw with the screwdriver. If both remaining wires have black insulation, choose either wire.

Step 5

Insert the end of the remaining wire into the NEMA 6-50 plug's remaining wire terminal -- the terminal that connects to the large prong. Tighten the terminal screw with the screwdriver.

References & Resources