Pull the cables into the junction box. Most junction boxes have holes in their sides, called “knock outs. All of the cables should enter through different holes and. From Easy to Pro In this comprehensive tutorial, I demonstrate four essential techniques for connecting stranded wires, each with its own strengths and applications. From basic twists to soldering and cri. A junction box is used to add a spur or to extend circuits and direct power to lights and additional sockets. Understanding the fundamentals of how to properly wire within a. Learn how to install a junction box safely, from choosing the right box and mounting it correctly to making secure splices and following basic code-safe practices.