[NLRS] Power Poles

[Dr. Gerald N. Johnson, electrical engineer]

AC, DC, automotive, aircraft, and electronic circuits all have their own
set of wire color codes and they overlap.

I dislike the powerpole connector family. As I see it, they use the
plastic shells to hold the contacts together. Plastic flows under
pressure to eventually relieve that pressure. That makes for poor long
term reliability of contact and I was taught at Collins in 1963 that
using plastic to hold any electrical connection was not an acceptable
practice. Not even to use the mounting screw for a Jones barrier strip
(as hard a thermoset plastic as there is) to ground a cable braid.

Now using the powerpole family depending on color codes seems to me to
be leading to disaster. In the near dark, or illuminated by a
monochromatic light source (single color LED or low pressure sodium
vapor street light) the colors may be easily mixed (or used by the
partially or fully color blind). Can that box made for 5 volts handle
+28? Probably not. If it could it would be running off 28 volts! Unless
you shuffle the stacks of power pole you will have interchangeable
connections based only on color. Suppose you have a helper setting up
the rover, who thinks your set of colors are because you couldn't find
all to match and plugs at random. The power poles will accept the wrong
load, though the load may not survive the wrong voltage.

I prefer to use none interchangeable connectors. I use Cinch-Jones P404
and J404 for 12 volts high current. I connect two pins in parallel for
positive and negative. Has worked for me since decades before the power
pole family was invented. Then I use 3 pin Jones P303/J303 for 24 volt
station power. More than one piece of equipment here has used the small
4 pin Jones (P-304/J304) for 12 volt power. I used 6 pin Jones for
equipment control interconnections including HF.

One could use a 6 pin Jones plug and jack for all applications. Use one
pin for ground, one pin for +5, one for +12, one for +28 and one for
-20. Then once its wired right, any plug can go in any jack and always
be connected correctly. Far safer than protection merely by color code.
Using different pins on the same connector for different voltages
simplifies stocking spares also. Makes it simpler than using a different
connector arrangement for a different voltage, but either is fairly
safe. The only unsafe problem is that one can't go by pin number if you
buy Beautech connectors that mechanically interchange with Cinch-Jones,
but use different pin numbers (and Beautech seem to come from Japan and
have been used in some Japanese VHF gear).

The voltage drop/contact resistance specifications of the venerable
Cinch-Jones are not as good as those for molex round pin connectors.
Some of that is conservatism, some is unmet claim. I believe the Jones
plugs will give the same contact resistance for decades after the molex
pins have lost their contact tension and are fully open circuits.
Certainly, I'm biased, by experience. Power circuits are boring, I only
want to do them once and have them work forever.

73, Jerry, K0CQ

-- 
Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.