introduction

The electrical design professional should determine a building's electrical load characteristics early in the preliminary design stage of the building to select the proper power distribution system and equipment having adequate power capacity with proper voltage levels, and sufficient space and ventilation to maintain proper ambients. Once the power system is determined, it is often difficult to make major changes because of the coordination required with other disciplines. Architects and mechanical and structural engineers will be developing their designs simultaneously and making space and ventilation allocations. It is imperative, therefore, from the start that the electric systems be correctly based on realistic load data or best possible typical load estimates, or both because all final, finite load data are not available during the preliminary design stage of the project. When using estimated data, it should be remembered that the typical data applies only to the condition from which the data was taken, and most likely an adjustment to the particular application will be required.

Although many of the requirements of building equipment, such as ventilating, heating/cooling, lighting, and so forth, are furnished by other disciplines, the electrical design professional should also furnish to the other disciplines such data as space, accessibility, weight, and heat dissipation requirements for the electrical power distribution apparatus. This involves a continuing exchange of information that starts as preliminary data and is upgraded to be increasingly accurate as the design progresses. Documentation and coordination throughout the design process is imperative.

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