Electrical Junction Boxes for Home Wiring Selecting the Right Junction Box for Home Wiring Projects. Application: Installing a Junction Box. Skill Level: Intermediate to Advanced – Best performed by a Certified Electrician or Electrical Contractor. Tools Required: Basic Electricians Pouch Hand Tools and Voltage Tester. How to Install Electrical Wiring | DoItYourself Adding New Wiring From a Junction Box. To tie in the new wiring, first locate the main supply wire by tracing the white wires, as all of these will be attached to the white wire on the supply line. Take out the unused plug and run the new wiring from the box. Clamp the cable to secure it to the junction box.