Color-coding of cabling, road cases, speakers, etc. is one of those “how do you know that?” questions I get all the time. In all honesty, I have to blame my eighth grade industrial arts teacher (in electronics shop) for the lifelong passion into all my esoteric electronics knowledge. But, of course, it was 1974, and my first project was a one-tube AM radio. I remember a lot of both the good and bad habits of electronics from that class; bad things like how to toss molten solder from the iron-tip toward other classmates, and good things like the color code.
For those of us old enough to remember, there was a sentence commonly used as a memory device, which by today’s standards is considered to be “inappropriate.” The first letter in each word of the sentence stood for a color: Black, Brown, Red, Orange, Yellow, Green, Blue, Violet (Purple), Gray and White. If you don’t know the memory device sentence, ask someone with a bit of gray hair. Just don’t repeat it in “polite“ company. These colors also have numeric representation as 0 through 9.
Why Color Codes Exist
The reason these color codes exist is because electronic components like resistors, capacitors and inductors commonly had stripes or dots of color to represent a numeric value in ohms, farads or henries. These colors also used the colors as base 10 power multipliers, plus silver and gold colors were added to indicate part quality in the form of tolerance of the value. As a teenager, I used to buy experimenter grab bags of unsorted
components and make sport of how fast I could identify a part at a glance. For example, a resistor with yellow violet orange and silver stripes was a 47k-ohm resistor with a +/-10% value tolerance.
This even went back before my 1937 RCA console radio were I could identify a burnt power resistor because it had one red dot on a brown painted form to signify a 200 ohm value. The reason why color codes go back so far in history is that painting stripes and dots was simpler technology than imprinting letting, and much easier to read in poor lighting of a chassis. Table 1 shows this standard electronic component color code.
Cabling
This relates to live sound because a commonly trained staff can then understand how the colors have meaning to stage gear. A good example is my Speakon cabling that I have with three standard lengths of 15, 30 and 50 feet. The 50-foot coil of cable has a green stripe of electrical tape near the Speakon NL4 plugs as a reminder that green means “5” or a 50-foot length. Likewise, my 30-foot speakon patches have orange tape stripes for “3” or 30-foot designations. To make things a bit more complex, my 15-foot speakon patches have a brown stripe followed by a green stripe, which means “1 5 “ or 15 feet of cable.
I do this to my standard Edison (NEMA 5-15) power cords as well, in which I keep 10, 15, 25, 50 and 100-foot lengths. Since the jacketing of these SJEOW and SEOW cables is black, I had to break the rule a touch since black electrical does not really show up or mean much to anybody. So 10’ extensions are brown, 15’ is brown-green, 25’ is red-green, 50’ is green and 100’ is a single white stripe. As long as my stagehands, techs and engineers are reasonably trained, everything gets found and put back in its work trunk.
Other Codes
There are so many color codes that keeping them straight is maddening. Codes like standard single-phase AC wiring (black=hot, red=hot, blue=hot, white=neutral, and green=ground) are necessary for distro maintenance. But the color codes for low-voltage HVAC or Telephone/Cat5 systems can drive you to tears. Unfortunately, we better start getting Cat5 color code literate pretty soon if digital consoles become standard equipment everywhere. If you need that color code refresher, check the back issues for my piece Ethernet audio (also in the book, page 76).
One ancient color code I want to lay on you is the old radio chassis wire colors that may be handy. Since I spend plenty of time fooling around with guitar effects pedals, having standard coding for ins and outs and power connections is necessary. Stated plainly yellow is for inputs, blue for outputs, red is DC power positive, black is DC power return/negative, green is ground and white is a free color for control wiring. This code goes back to the vacuum tube days where brown was tube filament and pilot light wiring. Old as it is, I still find it a handy way to sort things out.
If you have a handy color code, send me an e-mail and state your preferences and/or rationale.
