Electric power transmission is the bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation. The interconnected lines which facilitate this movement are known as a transmission network. This is distinct from the local wiring between high-voltage substations and customers, which is typically referred to as electric power distribution. The combined transmission and distribution network is known as the "power grid" in North America, or just "the grid". In the United Kingdom, the network is known as the "National Grid".
A wide area synchronous grid, also known as an "interconnection" in North America, directly connects a large number of generators delivering AC power with the same relative frequency, to a large number of consumers. For example, there are four major interconnections in North America (the Western Interconnection, the Eastern Interconnection, the Quebec Interconnection and the Electric Reliability Council of Texas (ERCOT) grid), and one large grid for most of continental Europe.
An electrical contractor is a business person or firm that performs specialized construction work related to the design, installation, and maintenance of electrical systems?a $130 billion industry in the United States.1
An electrical contractor is different from an electrician; an electrician is an individual tradesman and an electrical contractor is a business person or company that employs electricians. Both usually hold licenses and insurances to properly and safely operate a business, protecting the employees and home owners/business owners from insurance liabilities. These requirements vary from state to state. Electricians may work for an electrical contractor, or directly for individuals or companies.
Electrical contractors employ workers in many capacities, determined by their level of training and experience. Some common jobs include:
Apprentice Electrician ? Receives on-the-job training and classroom instruction from licensed journeymen or master electricians about how to install, modify, repair, and maintain power and lighting systems. Most apprentice programs last 3 to 5 years and apprentices earn wages during this training period.2
Journeyman Electrician ? Installs, modifies, repairs, and maintains power and lighting systems. Reads blueprints, terminates cable, and installs and troubleshoots control wiring from drawings. Has completed the apprentice program and holds a journeyman's license (according to state requirements) and supervises apprentices.
Estimator ? Calculates a project's duration and cost, including materials, overhead, and labor. This estimate is often submitted as a bid on a project and serves as a scheduling and budget guideline as the project proceeds.
Project Supervisor ? Oversees workforce to encourage safe and high-quality installations. Monitors progress to meet project deadlines. Submits required reports and forms.
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