Install all junction boxes per NEC regulations. All wires to be connected with UL approved wire nuts. Our team is committed to delivering honest, objective, and independent reviews on home. 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. To install a junction box correctly, choose a box that matches the wiring method and environment, mount it securely, bring cables in. A junction box is used to add a spur or to extend circuits and direct power to lights and additional sockets. To install one, you'll need to strip the ends off all the wires that will be in the box.