When it comes to books, there are many that can be helpful if you work with electricity or electrical installations in any way, but there is certainly one ‘bible’ that a lot of people absolutely have to make sure that they turn to each year. The NEC or National Electrical Code book is one of the most commonly sought after guides in many industries, not the least of which is construction. This is a publication put out on a regular basis and the 2011 National Electrical Code is the latest edition of it.
If you work with anything electrical then this is an absolute must have and that includes whether you work on HVAC systems or in wiring homes or any other kind of electrical work. The purpose of the National Electrical Code book is to go over the regulations and codes that apply to electrical installations so that a fairly standardized level of safety can be achieved across the United States. This book is, however, used in many other countries which value the codes to help them do things more efficiently and with a greater level of safety.
2011 National Electrical Code Books
The 2011 National Electrical Code is an excellent resource that you are certainly going to want to make sure that you invest in. While it is not federal law per say, it is definitely what a lot of local, county and state laws or regulations are based on. You can expect to gain a lot from being familiar with its contents.
In type NM cable, conductor insulation is color-coded for identification, typically one black, one white, and a bare grounding conductor. The National Electrical Code (NEC) specifies that the black conductor represent the hot conductor, with significant voltage to earth ground; the white conductor represent the identified or neutral conductor, near ground potential; and the bare/green conductor, the safety grounding conductor not normally used to carry circuit current. Wires may be re-coloured, so these rules are commonly excepted. In 240-volt applications not requiring a neutral conductor, the white wire may be used as the second hot conductor, but must be recolored with tape or by some other method. Four-wire flexible equipment connection cords have red as the fourth color; unlike older European practices, color-coding in flexible cords is the same as for fixed wiring.
Electrical wiring practices developed in parallel in many countries in the late 19th and early 20th centuries. As a result, national and regional variations developed and remain in effect. (see National Electrical Code, electrical wiring, electrical wiring). Some of these are retained for technical reasons, since the safety of wiring systems depends not only on the wiring code but also on the technical standards for wiring devices, materials, and equipment.