To enable wires to be easily and safely identified, all common wiring safety codes mandate a colour scheme for the insulation on power conductors.
In a typical electrical code, some colour-coding is mandatory, while some may be optional.Many local rules and exceptions exist per country, state or region.1 Older installations vary in colour codes, and colours may fade with insulation exposure to heat, light and ageing. As of March 2011, the European Committee for Electrotechnical Standardization (CENELEC) requires the use of green/yellow colour cables as protective conductors, blue as neutral conductors and brown as single-phase conductors.2 The United States National Electrical Code requires a green or green/yellow protective conductor, a white or grey neutral, and a black single phase.3 The United Kingdom requires the use of wire covered with green insulation, to be marked with a prominent yellow stripe, for safe earthing (grounding) connections.4 This growing international standard was adopted for its distinctive appearance, to reduce the likelihood of dangerous confusion of safety earthing (grounding) wires with other electrical functions, especially by persons affected by red-green colour blindness. In the UK, phases could be identified as being live by using coloured indicator lights: red, yellow and blue.
The kilowatt hour (symbol kWh, kW?h, or kW h) is a derived unit of energy equal to 3.6 megajoules.
The kilowatt-hour is commonly used as a billing unit for energy delivered to consumers by electric utilities. The symbol "kWh" is commonly used in commercial, educational, scientific and media publications, and is the usual practice in electrical power engineering. Other abbreviations and symbols may be encountered: "kW h" is less commonly used.
It is consistent with SI standards (but note that the kilowatt-hour is a non-SI unit).
Many electricians who start their own business providing electrical services decides on all day business profile.
This is of course, much more strenuous work system, but still so that you can greatly increase the number of customers using the services of a particular company.
Such flexibility electrician to ensure that customers who are in the house there was a failure can ask for help at any time.
This is important especially in larger cities, because living people there lead a very busy lifestyle and therefore the repair will be carried out for example in the evening..