of green/yellow colour cables as protective conductors, blue as neutral conductors and brown as single-phase conductors. Sweden In Sweden, IEC 60364 is implemented through the national standard SS-436 40 000. Notable is the exception for blue, where while the colour normally is used for neutral may be used as connecting wire between switches and between switch and fixture, as well as phase wire in a two-phase circuit , all under the condition that no neutral wire is used in the particular circuit. United Kingdom The United Kingdom requires the use of wire covered with green/yellow striped insulation, for safety earthing (grounding) connections. 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 2004, the UK adopted the European Union standard for phase colours of brown, black, and grey, and for neutral, blue. However, the old phase colours of red, yellow, and blue with black for neutral are still found in old installations. Single-phase wiring should strictly be in brown (red in old system), regardless of which phase it originated from, but it is common practice to use three-core cable in the three-phase colours for two-way lighting switches. The accepted practice is to sleeve the ends of the cores in brown or blue sleeves as appropriate. United States The United States National Electrical Code requires a bare copper, or green or green/yellow insulated protective conductor, a white or grey neutral, with any other colour used for single phase. The NEC also requires the high-leg conductor of a high-leg delta system to have orange insulation, or to be identified by other suitable means such as tagging. Prior to the adoption of orange as the suggested colour for the high-leg in the 1971 NEC, it was common practice in some areas to use red for this purpose. The introduction of the NEC clearly states that it is not intended to be a design manual, and therefore creating a colour code for ungrounded or "hot" conductors falls outside the scope and purpose of the NEC. However, it is a common misconception that "hot" conductor colour-coding is required by the Code. In the United States, colour-coding of three-phase system conductors follows a de facto standard, wherein black, red, and blue are used for three-phase 120/208-volt systems, and brown, orange or