Determine the system's needs and individual components. In residential structures, the electrical needs of a family change over time. Room additions may be added to the structure for additional family members. The electrical panel board needs to be designed to accommodate these changes. Make a list of the immediate needs and long term needs. If additional electrical components will be added in the future, the panel needs to be large enough to accommodate those components. List all the components that will be controlled from the panel.
Look up the electrical codes required for the project. Even the panel's casing must be constructed from materials approved by the electrical codes. Electrical codes can be acquired at the State's Building Standards Commission's website. Make a list of acceptable panel material and any information pertaining to the panel's wiring such as breaker loads.
Draw a rough sketch of the panel board. Start by drawing the outline of the panel's face. Determine a logical sequence of locations for the panel's components. Panel components, such as switches, should be easy to access and grouped in clusters according to use. If the panel controls devices on either side of it, the switches for the devices should be clustered accordingly. Design the panel so that any controls or switches are place in logical locations.
Create the finished drawing. The finished drawing needs to be full size because it will serve as a template when the panel is built. A full size drawing also allows the designer to check the ergonomics of the design. With the exception of breakers, which are stacked together, allow as much space between panel devices as possible. Use a ruler to layout the drawing. Make two copies of the finishing drawing.
Build a mock-up. Using cardboard, create a life size mock-up of the panel board. Use a utility knife to cut a piece of cardboard to the same size as the panel. Spray artist's spray mount onto the cardboard. Take one of the finished drawings and mount it on to the cardboard, placing it directly on the sprayed surface. This provides a life size model of the panel.