The largest enclosure is known by several names, including the Main Service Panel, Load Center, or Breaker Panel. This metal cabinet acts as the central command post for the entire electrical system after receiving power from the utility company. It is the most commonly used raceway because it can be concealed or surface mounted, it is low cost, light weight and doesn't require threading tools like rigid. And some of them sound like they were made by a sparky with a really sick mind. Junction Box: Specifically designed for joining or branching electrical wires. All connections must be contained within the box. Round Bell Box = Bagel Pagel, coined by an esteemed colleague from Haggard Electrical Contractors who's last name is Pagel! Connects and separates two boxes while building a raceway between them. Adjustable sliding scaffold board. Feeder pillars might be supplying.