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[aprssig] 12V wiring ideas

Al Wolfe alw.k9si at gmail.com
Sat Oct 29 20:39:14 UTC 2011


    Must be deja vu again. This comes up here and other groups from time to 
time.

    The Air Force outlawed soldered inline connections for most applications 
in airplanes at least fifty years ago because of the solder wicking problem 
mentioned earlier. However, soldering is widely used inside airborne 
equipment racks and on some of the connectors to these racks. They did tend 
to use wire that had finer stranding than what we amateurs use so the abrupt 
junction to where the wicking stopped was probably more pronounced. And 
airplanes are probably subject to a lot more vibration than a typical ham 
install.

    I think that the idea of running the ground (negative conductor) 
probably originated with the CBers who thought they could get a little more 
power out with a direct connection to the battery. As others have mentioned, 
this idea is fraught with problems and potential problems. Twice as much 
exposure to ignition noise, expense of twice as much wire, twice as much 
voltage drop, etc, etc. Having done mobile installs professionally off and 
on since the early 1960's, I think I have a pretty good feel for it by now. 
The trunk mount installs almost always ran the hot wire to a fuse block next 
to the battery and the ground went to the nearest chassis or frame location. 
Sometimes the hot ran to an accessory connection under the dash. I never 
heard of running a wire to the battery for ground until probably the late 
1970's during that CB craze.

    FWIW, it's pretty safe to put a larger fuse in the ground lead if you 
think you still need one. No need to blow two fuses.

    With all the plastic in today's vehicles, finding a local ground in the 
cabin area can be a challenge. If nothing else follow the negative for the 
cigarette lighter for a clue to a decent grounding point. I've also used 
seatbelt anchor points.

    Powerpoles have become a standard connector, like them or not. I have 
been using them on everything for many years with never any problems of them 
coming apart by accident. And if someone kicks a wire I'd much rather it 
come disconnected than be pulled out of a connector. If a Powerpole 
connection gets pulled apart it's easy to hook it back together. Not so easy 
with ring connectors.

    Powerpoles meet my needs quite well. I've tried many different kinds of 
connections over the years and Powerpoles are by far the best for me. (I 
have the proper crimpers but do admit to soldering a few of them.)

73,
Al, K9SI, retired, mostly














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