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The international standard IEC 60446 Basic and safety principles for man-machine interface, marking and identification - Identification of equipment terminals, conductor terminations and conductors was a standard published by the International Electrotechnical Commission (IEC) that defined basic safety principles for identifying electrical conductors by colours or numerals, for example in ...
In commercial construction, three-phase circuits are often used. Common 3 phase configurations within a building are 208v/120 wye, 120/240 center tapped delta and 480v/277v wye. Lighting is usually fed by 277 V or 120v. Countries such as Mexico may adopt the NFPA standard as their national electrical code, with local amendments similar to those ...
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 violet, and yellow are used in 277/480-volt systems. (Violet avoids conflict with the NEC's high-leg delta rule.)
Electrical installations Wiring practice by region or country North American practice United Kingdom practice Regulation of electrical installations BS 7671 UK wiring regulations IEC 60364 IEC international standard Canadian Electrical Code (CE Code) U.S. National Electrical Code (NEC) Cabling and accessories AC power plugs and sockets Cable tray Electrical conduit Mineral-insulated copper ...
The cable core colours are described in IEC 60304 (1982-01), Standard colours for insulation for low- frequency cables and wires. The three-phase phase colours are brown, black and grey instead of red, yellow and blue. Where a circuit includes a neutral or mid-point conductor identified by colour, the colour used shall be blue.
In the United States it is not usually used for three phase power but for the high leg delta wiring of split-phase electric power (unknown in Europe). This allows one to choose single-phase AC power at either 110–120 volts between phase and neutral or 220–240 volts between phase and phase.
Conductors of a three-phase system are usually identified by a color code, to facilitate balanced loading and to assure the correct phase rotation for motors. Colors used may adhere to International Standard IEC 60446 (later IEC 60445 ), older standards or to no standard at all and may vary even within a single installation.
As an example, the 5-15R is the common 125 V two-pole, three-wire receptacle rated for 15 A. The L5-15R, while sharing the same electrical rating, is a locking design that is not physically compatible with the straight-blade 5-15 design. The 5-30R has the same two-pole, three-wire configuration and 125 V rating, but is rated for 30 A.