A lot of us use Anderson PowerPole connectors for DC power distribution. There’s a nearly universal standard to use red and black housings for 12 volt-ish (e.g., 13.8) lines, with the housings arranged per the “Orange County RACES Standard” like so:
Of course, to make things more interesting, my Anan 7000DLE radio uses the opposite arrangement. Sigh…
It turns out that PowerPoles can be had in several different colors, and as my station/lab wiring became more complex I decided to standardize on different colors for different voltages/polarities. I haven’t found a widely-accepted convention for this, so decided to come up with my own:
* Some 48V gear is technically -48 and that argues for perhaps reversing the pin arrangement since ground is the most positive side. But the gear I’ve worked with so far has all had isolated grounds and normal wiring works fine, so I’m doing things the normal way.
Another issue is standards for non-power-distribution use, such as push-to-talk signals. Personally, I’d rather not use PowerPoles for that, but others do. We’re still working on color coding, but I am suggesting that control connectors be wired anti-OCRACES (e.g., black on the left when facing you as in the picture above). That will help make it obvious that you’re plugging things together that you shouldn’t.