There are exposed wires and concealed wires. Most of the concealed wires are through pipes and hidden in the building wall or decorative wall. Inside the box, you'll find things like circuit breakers, busbars, terminal blocks, and wires. Whether you're an electrician or a DIY enthusiast, this tutorial will help you understand the fundamentals of wiring a. A subpanel is a smaller service panel that enables power distribution to specific areas of your building or home. It integrates power distribution, protection, and monitoring capabilities, and is responsible for distributing power to entire commercial or residential. An electrical sub panel, also known as a sub distribution board or sub circuit breaker panel, is a smaller secondary panel connected to the main electrical panel in a building.