The transformer reduces the standard line potential to two dual voltage systems, which then pass through master switches and electric meters to record the subscriber's usage. Each voltage pair has a separate distribution system of wiring leading from the meters and master switches to circuit breaker panels, where it is further broken down into circuits similar to residential uses. Because electrical projects deal with high-voltage wiring is considered hazardous, the switches controlling overhead lighting use lower voltages, and each heavy machine has its own fused switch. From the circuit breaker panel, low-voltage power conduit and wiring is typically distributed through partitions and ceiling sandwich spaces, but, in large open areas of commercial buildings, there may be wire ways embedded in the floor slab.
Lamps range in size and wattage, and the available colors can range from warm white to cool white.
Each of these types of electrical project lamp is used in a variety of fixtures to produce different lighting conditions. Incandescent lamps can be placed in translucent glass globes for diffuse effects, or in recessed ceiling-mounted fixtures with various types of reflectors to evenly light walls or floors. Electrical project Fluorescent lamps are typically installed in recessed rectangular fixtures with clear prismatic lenses, but there are many other fixture types, including indirect cove lights and luminous ceilings with lamps placed above suspended plastic or metal egg crate diffuser grids. The zonal cavity method, which takes into account the lamps, fixtures, shape of room, and colors of room surfaces, is one example. The usual measure of light intensity is in foot-candles on a horizontal surface, such as the floor of a room or a desk.