DEC standard power wire colour coding
From Computer History Wiki
DEC PDP-11's generally use a common system of colours in the power harness which leads from the power supply to the backplanes, etc.
It is:
| Line | Colour |
|---|---|
| +20V | Orange |
| +15V | Grey |
| +15B (sometimes +12B) | White |
| +5V | Red |
| +5B | Red/white stripe |
| Ground | Black |
| -5V | Brown |
| -15V | Blue |
| -15B (sometimes -12B) | Green |
| ACLO | Yellow |
| DCLO | Purple |
| LTC | Brown |