3 Phase Wiring System Info

In 3 phase wiring, three wires of different colors are used and this technique is also known as 3 phase power. 3 phase wiring also has the neutral as well as Earth wire whose colors are also different. Neutral wire in three phase wiring permits only low voltage even the voltage is high. If the voltage is high then having neutral wire is not general.

Power load is balanced in 3 phase wiring system making it extremely organized. Current value also remains the same in all the three wires with balanced power load. 3 phase wiring system is not so common in residential wiring, where 1 phase wiring is done.

Conductors in 3 phase wiring have color codes and generally the color is country specific. Color code vary markedly or there may have a standard or no color code at all. According to the current National Electrical Code (2005), there is no need of color identification of conductorsexcept for the neutral having white or white with color stripe, the ground in green or green with yellow stripe and in case the circuit has High Leg Delta System then the high leg must have the orange color.

 

	L1	L2	L3	Neutral	Earth
North America	Black	Red	Blue	White	Green
North America (newer 277/480 installations)	Brown	Orange	Yellow	White	Green
UK until April 2006	Red	Yellow	Blue	Black	green / yellow striped (green on very old installations)
Europe (including UK) from April 2004	Brown	Black	Grey	Blue	green / yellow striped
Previous European (varies by country)	Brown or black	Black or brown	Black or brown	Blue	green / yellow striped
Europe, for busbars	yellow	green	purple	-	-

3 Phase Circuit Wiring Numbering
Three phase wiring system is given a circuit number. Circuit number standardization is important from the future troubleshooting point to view.

Black/Brown	Red/Orange	Blue/Yellow
1/2 7/8 13/14 19/20 25/26 31/32 37/38	3/4     9/10 15/16 21/22 27/28 33/34 39/40	5/6 11/12 17/18 23/24 29/30 35/36 41/42

 

Most commonly electric motor uses the 3 phase wiring system. The three phase motors are then used in different products like fans, pumps, compressors, blowers and other equipments such as electric boilers, bigger rectifier systems that are run by motors.

In 3 phase wiring the wiring is smaller and life of the motor is long. Even the chances of lighter motor to perform better is more.