The meaning behind the color of the wire
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September 25, 2021
Black, white, green, red, blue, orange, brown, and gray, the color of the insulating sheath outside the wire usually has its own meaning.
So, when you're playing with new fixtures, besides turning off the breakers , make sure that every colored wire you're going to touch has something to say.
There is no systematic color coding for residents to start using electricity, and there is not even a set of standards that are used correctly. In 1879, shortly after Edison first introduced electric lights, the insurance industry began to issue some safety guidelines.
The first formal guide appeared in 1881 and included addressing capacity, insulation and installation. However, the color of the wires is not classified.
The first National Electrical Code (NEC) was proposed by NBFU in 1897, and it also neglected the standardization of wire color problems.
Later in 1928, the NEC was updated and revised. One of the requirements was to establish a specification for the color of the grounding wire, which was later white or natural ash. It was also forbidden to apply these colors to the live and neutral lines.
Further color coding is a new version introduced by NEC in 1937. The color-coded lines are utilized with "multi-branch circuits", and the lines defining the three branches are black, red, and white. More branches can be added to other colors, such as yellow and blue.
In 1953, NEC changed the color of the grounding wire to green or bare wire. Green is also prohibited for use on circuit lines (such as live and neutral).
NEC's 1971 version encodes color multi-branch runs, although white, natural gray, green, and yellow-green stripes remain, and these colors are also prohibited for grounding.
This specification lost the stereotyped color coding requirements for the via wires because there is not enough color to distinguish the system, voltage, and circuit.
Red is the fire line, blue is the zero line, yellow or yellow and white are the most commonly used ground lines; yellow, green, and red represent the phase lines. It can also be said that the line of the fire line is charged.
Blue represents the zero line, which is generally uncharged, but also when there is electricity. That is, when the zero line is broken, the line is charged, and the two colors represent the ground line. This line is the safest.