Front- and rear-access switchboards align at the front and the rear. Bus maintenance and cable entry and exit require rear access. Their placement directly affects current capacity, heat dissipation, copper consumption, cabinet size, and even installation safety. If the main section is deeper than others, due to physical size of the main device, the necessary offset in lineup will occur in front, and the main section will be. A large single panel, frame, or assembly of panels on which are mounted on the face, back, or both, switches, overcurrent and other protective devices, buses, and usually instruments. In most assemblies you will find horizontal main bars, vertical risers, neutral and equipment-ground buses, and purpose-designed. Article 408 covers the specific requirements for switchboards and panelboards that control power and lighting circuits.
