Why Black and White

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innola

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I am in an AC electrical class and I asked the question of why is the color black used for hot and the color white used for neutral. Who chose these colors and why? The class and the instructor was at a loss for an answer. Is to help those who may be color blind?
 
Follow-on question and answer.

Follow-on question and answer.

Why does a Sperm Whale have such a small throat? Ans. That's the way it is.

It does not matter one whit why the hot conductor is black and the Neutral can be either Gay or White.

In point of fact, the hot conductor can be any color other than Gray, White or Green.:D
 
donf said:
...the Neutral can be either Gay or White.
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Or both?
:p

A few years ago we (UK) had this change imposed on us in order to harmonise within the EU:

Harmonisedcolours-1.jpg


Not many were happy with it, myself included.The potential for confusion between blue or black being either a live or a neutral.............
 
innola said:
I am in an AC electrical class and I asked the question of why is the color black used for hot and the color white used for neutral. Who chose these colors and why? The class and the instructor was at a loss for an answer. Is to help those who may be color blind?
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As far as the NEC I have no idea why white was chosen for the grounded conductor.

The ungrounded conductors can be any color but white, gray, green or bare.
 
Wild guess.

In the early days of rubber wire insulation, colors were very difficult, if not impossible to achieve, so other mechanical methods (i.e. tracer threads or ribs) were used. Along came thermoplastic insulation, which naturally was very light greyish/tanish/whitish or could be colored black by the addition of some simple coloring agent. Eventually, with improved chemistry and manufacturing techniques additional colors became available including 'pure' white.
 
jim dungar said:
Wild guess.

In the early days of rubber wire insulation, colors were very difficult, if not impossible to achieve, so other mechanical methods (i.e. tracer threads or ribs) were used. Along came thermoplastic insulation, which naturally was very light greyish/tanish/whitish or could be colored black by the addition of some simple coloring agent. Eventually, with improved chemistry and manufacturing techniques additional colors became available including 'pure' white.
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Thats a good guess, I like it...
 
My guess would be that they are on oppisite endes of the color spectrum. White being the absence of color and black being the inclusion of all colors. Now why not white hot and black neutral? Couldn't say.

One of the greatest tv scenes ever is Tim Taylor trying to fix the dis washer with his son. "so the sun is yellow and the sun is hot so the yellow wire should be the hot wire and the brown, well the earth is brown and so that would be the ground.....BZZZZZZZZ!"
 
I think that the history goes all the back to the early work in DC not AC!

White being the absence of color and black being the inclusion of all colors.
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I think you have that backwards White is inclusive and black is absent of color, perhaps you where thinking excluded.

Newton proved that a light spectrum existed in White light and that help set up other things. :)
 
jim dungar said:
Wild guess.

In the early days of rubber wire insulation, colors were very difficult, if not impossible to achieve, so other mechanical methods (i.e. tracer threads or ribs) were used. Along came thermoplastic insulation, which naturally was very light greyish/tanish/whitish or could be colored black by the addition of some simple coloring agent. Eventually, with improved chemistry and manufacturing techniques additional colors became available including 'pure' white.
Click to expand...
In my adolescent years I worked for a thermoplastics manufacturer, which compounded vinyl (the most common thermoplastic wire insulation) and also made (shaped) products of other thermoplastic types. Most thermoplastics' natural color ranges from translucent to off white. This color is also called the materials' neutral color. I believe this is how white got associated with the neutral conductor.
 
I would think that the color scheme predates the plastics industry. When did

plastics take off as an industry ? 1947 to 1950 maybe. The Graduate was

1968. 480 what do your code books have to say ?
 
Why.....in my opinion...for common practice...so everyone understands the same use of the conductor(s), as they are applied/used.
I thought there was a section in 110, 300, or 310 that identifed conductor colors, but I can only find in the 2011 NEC grounded conductor identification in 200.6 and equipment grounding conductors in 250.119.
 
David A Engelhart said:
I thought there was a section in 110, 300, or 310 that identifed conductor colors, but I can only find in the 2011 NEC grounded conductor identification in 200.6 and equipment grounding conductors in 250.119.
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There are a few areas that call for specific colors for ungrounded conductors, see 110.15, 230.56, and 517.160 but in general they are not called out.

424.35 might also be of interest.

Roger
 
John120/240 said:
I would think that the color scheme predates the plastics industry. When did

plastics take off as an industry ? 1947 to 1950 maybe. The Graduate was

1968. 480 what do your code books have to say ?
Click to expand...
Perhaps... but prior to plastics was rubber insulation, and the same applies though the natural color of rubber is on the yellowish side of off white.

More than likely it has to do with basic colorimetry, whereas white, black, and in-between shades thereof (shades of gray), are known as neutral colors... but black being the absence of color (additive, i.e. light), left white at the far end, then gray as an alternate.
 
cadpoint said:
I think that the history goes all the back to the early work in DC not AC!



I think you have that backwards White is inclusive and black is absent of color, perhaps you where thinking excluded.

Newton proved that a light spectrum existed in White light and that help set up other things. :)
Click to expand...

White light contains light of all frequencies. In that sense, white is a
combination of all colors. Black objects absorb light of all frequencies.
This means that very little light is reflected from them. Black is the
absence of light.

As far as the absence of color is concerned... you know that if you combine
pigments or dyes of different colors, you don't end up with white. Dyes
and pigments work by absorbing light in certain frequency ranges, and
transmitting or reflecting light of other frequencies. If two different
dyes are combined, the mixture absorbs light characteristic of BOTH dyes,
and transmits light of the remaining frequencies. If you mix togtether
dyes that are truly complementary, the mixture will absorb light of all
frequencies, and thus be black. (In practice the best you can do is get a
muddy brown, because the different dyes are only approximately
complementary.) So it depends on what you mean by "absence of color."

We perceive colors because we have three types of "cone" cells in our
retinas, each of which is most sensitive to certain frequency ranges.
These ranges correspond pretty much to red, green, and blue. Our brain
interprets the different intensities of the signals from each type of cone
cell to decide what color it sees.
 
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