Wikipdia about history of wiring
The first interior power wiring systems used conductors that were bare or covered with cloth, which were secured by staples to the framing of the building or on running boards. Where conductors went through walls, they were protected with cloth tape. Splices were done similarly to telegraph connections, and soldered for security. Underground conductors were insulated with wrappings of cloth tape soaked in pitch, and laid in wooden troughs which were then buried. Such wiring systems were unsatisfactory because of the danger of electrocution and fire, plus the high labour cost for such installations.
Where you can find National Electrical Code
The NEC is available as a bound book containing approximately 1000 pages. It has been available in electronic form since the 1993 edition. Although the code is updated every three years, some jurisdictions do not immediately adopt the new edition.
The NEC is also available as a restricted, digitized coding model that can be read online but not saved, copied and pasted, or printed, free of charge on certain computing platforms that support the restricted viewer software.
In the United States, statutory law cannot be copyrighted and is freely accessible and copyable by anyone. When a standards organization develops a new coding model and it is not yet accepted by any jurisdiction as law, it is still the private property of the standards organization and the reader may be restricted from downloading or printing the text for offline viewing. For that privilege, the coding model must still be purchased as either printed media or a CD-ROM. Once the coding model has been accepted as law, it loses copyright protection and may be freely obtained at no cost.
Archive.org and many state or local government sites allow download of the NEC without the registration that the NFPA requires.
External links to both the restricted NEC online access and free public access sites are referenced at the end of this article.
Job opportunities in large enterprises
Large industrial plants require continuous supervision by electricians. In such places, electrical work, after-hour, including the usually public holidays and so on. Often continuity of production makes the conduct of such processes is profitable. Production plants are often places where electricity specialist can find a well-paid job. This involves a number of responsibilities for the most number of installations. Moreover, work in the industry can find a lot of people, because the large volume production is accompanied by high employment, also in the field of electrical engineering.