How to Install a Three-Phase 240V

Shut off power to the main power panel. Remove the breaker panel cover using the screwdriver. Choose the next two vacant slops in the power panel to place the new circuit breaker.

Push the Romex wire up into the power panel through one of the knockout holes in the bottom of the power panel. Strip 1/2 inch of insulation off the ends of the red, black, and white wires of the Romex cable. The new breaker has two terminals.

Connect the black wire to one of the two breaker terminals and connect the red wire to the second breaker terminal. Tighten these terminals with the screwdriver, but do not plug the breaker into the power panel yet. Next, connect the ground wire and the white neutral wire to the neutral/ground bus bar if this is a main power panel. If this is a subpanel, the white wire will connect to the neutral bus bar and the ground wire will connect to a separate ground bar. This helps maintain proper grounding of the subpanel.

Plug the new double pole breaker into the chosen vacant spot in the power panel. Make sure the new breaker is turned to the "Off" position until the equipment installation is complete at the other end of this circuit. This article assumes that that equipment is already in place or will be installed at a later date.

Use the screwdriver and hammer to knock out the corresponding knockout slots on the breaker cover that line up with the new breaker. Set the breaker cover in place and reinstall the screws which hold the breaker cover in place.