We have become dependent on electricity as a part of our daily lives. It powers all of our entertainment devices, support systems, appliances and HVAC (Heating, Ventilating, and Air Conditioning). It is so common, that we naturally assume that it is installed into every home in the United States. Electricity is probably the most used utility, yet often, little attention is given to its safe installation and total power provisions. Thankfully, hydro utilities require intense inspections of the connections and quality of work at the service, rough, and finish electrical stages of all installations, controlled by government codes. Broken down, there are two main divisions to electrical utility services. The service connections, and the power distribution systems.
All service connections require an electrical line to be run, either underground or overhead, to a meter then on into a main shut off and panel box. The meter will display how much power is used and is utilized for billing customers. Main shut offs are mandatory, and allow for the total disabling of the entire electrical system within the building. The panel box, provides space for distributing power to independent sources, while prevent the possibility of overloading wires, which can easily become hot and start a fire. Most service connections are 100 or 200 amps, typically 200 when electric heating is used. Utility companies will often provide the connection from existing hydro poles, to the overhead mast or utility pole when underground lines are run. The service is supplied with a ground wire, which is grounded to the earth by either a rod or grounding plate, a neutral line and two power supply lines. This type of cable is capable of supplying 120 volts for single power connections or 240 volts for two wire power connections Commercial Electrical Services.
The power distribution system is a network of cables which connect to every electrically operated mechanical, outlets and light source in the home. The cables are generally run inside the wall, roof and floor assemblies, in areas where they will not be exposed to damage or view. These cables all have a ground connection, a neutral line and one or two power supply wires for 120 or 240 volt connections. All utility outputs and equipment are connected to a common grounding system to prevent shock hazard. The entire home is connected to 120 volt power supply cables with the exception of major appliances such as stoves or dryers, and utility mechanicals such as furnaces or well pumps, which run on 240 volts.