Ans. The board units or "slabs" should be of small dimensions, to avoid the liability of breakage and expense of renewal when a unit becomes cracked or machine injured.
Figs. 2,834 and 2,835.—Front and rear views showing General Electric automatic voltage regulator mounted on switchboard panel.
Ordinarily, switchboards vary from five to eight feet in height and the widths of the panels vary from five to six feet. In some boards the seams between the slabs run vertically, and in others horizontally. In order to render the assembling of the switchboard as simple as possible, and its appearance when finished the most artistic, these seams should run horizontally rather than vertically. The edges of each of the slabs should also be chamfered so that there will be less danger of their breaking out when being mounted on the framework.
Ques. In assembling a switchboard, how should the lower slabs be placed, and why?
Ans. They should be suspended a little distance from the floor to prevent contact with any oil, dirt, water or rubbish that might be on the floor.
Ques. How are the slabs or panels supported?
Ans. They are carried on an iron or wooden framework with braces to give stability.
The braces should be securely fastened at one end to the wall of the station, and at the other end to the framework of the board, as shown in [fig. 2,836].