An electrical contractor - from Wikipedia
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.
How to plan the laying of electrical wiring?
Laying the electrical system not only at home, but each object is not the simplest of tasks. First of all, you must have the appropriate skills in the field of electrical engineering. You must also have knowledge typically technical, that is how laid the cables, where assembled the so-called cans, and how spread out the electrical system, if we consider the whole house. Specific challenges are posed by various types of sockets and switches located in such areas, like the kitchen or bathroom. That is where there is the greatest danger, and to correctly assemble the installation you have to have not only knowledge but also experience.
Worth to know - AC Power
Power in an electric circuit is the rate of flow of energy past a given point of the circuit. In alternating current circuits, energy storage elements such as inductors and capacitors may result in periodic reversals of the direction of energy flow. The portion of power that, averaged over a complete cycle of the AC waveform, results in net transfer of energy in one direction is known as active power (sometimes also called real power). The portion of power due to stored energy, which returns to the source in each cycle, is known as reactive power.