Electrical services and associated systems are an integral part of a building. The use of electricity and associated electronic devices within a building are increasing, especially as technology and automation within buildings’ increase. Electricity can be dangerous, therefore a good understanding of electrical systems, along with typical maintenance and common repairs is essential for the successful operation of a building.
Electricity is generated by power companies using fossil fuels, nuclear power or renewable energy sources at sites across the country. It is then distributed at high voltages (which is more efficient), before being locally stepped down via transformers to lower voltages, before entering buildings. Electrical systems on this website will focus only on the incoming supply and systems within a typical building; and not the generation, supply or distribution of electric outside of a building.
Electricity for use in residential, commercial and industrial buildings is generated as an alternating current (AC) supply. For residential use, a single AC supply is usually sufficient, but in larger buildings 3-phase supplies are often required to power larger loads. In the US 120-volts is the standard receptacle/appliance voltage for the majority of applications however, alternative higher voltages are supplied dependent of a buildings’ size, use and occupational power requirements. For example, higher voltages are often required in commercial and industrial buildings to power large, heavy duty items and data centers. Power is typically supplied from utility-owned transformers which are installed at grade level or from overhead lines and poles. Power then enters the building underground or overhead where it typically enters a main disconnect and/or switchboard and electric meter, before being routed to panelboards within the building. Panelboards either serve the entire building, or supplies are branched off to smaller sub-panels. In some installations, backup power generation (usually by a fuel-powered generator, or battery backup supply) is required for maintaining life-safety systems in the event of a power outage. Finally, in addition to power systems, electronically controlled and operated security and access control systems are often found in buildings.