Ron Hebbard wrote on Tue, 27 September 2005 08:31 |
David Buckley wrote on Tue, 27 September 2005 13:21 |
mississippi slim wrote on Tue, 27 September 2005 18:01 | Don't be afraid to "tin" the conductor leads before you clamp em down. Keep it Pro.
|
I would suggest that is controversial advice. Arguments rage on, but I'm in the "dont tin" camp.
|
Hello David;
And I'm in that same "camp" right along with you. I was just beginning to write a post when I heard you chime in. I suppose I could go with tinning the very tip but most tinners opt to tin the entire exposed end even to the extent of wicking solder up inside the insulation.
To elaborate; Tinning hardens the end. When you clamp it, no matter how tight you make it, all it takes is the slightest loosening to have a totally poor connection.
Toodleoo! Ron Hebbard
|
It's worse than that. Tinning stranded wire is not reliable with fixed compression type terminations. That includes lug and screw terminals, crimp on terminals and terminals with parallel jaws (like Phoenix connectors). The only compression type connections that are reliable with solder dipped wire are spring loaded types that maintain a consistent force even if the wire shifts or flows.
The problem is cold flow deformation of the solder. When you tighten down a screw on a solder tinned wire, the solder initially resists the compression force giving the impression of a tight connection. Over time, the solder yields to the pressure and a loose connection occurs. You can solder dip wires for soldered connections without creating this problem although it can increase the likelihood of wire breakage in high vibration applications.
Cold flow deformation is one of the reasons why aluminum household wiring has such a bad reputation. Aluminum is softer than copper and requires special connectors to be reliable
http://www.eh.doe.gov/docs/sn/nsh9001.html. This is the same mechanism that happens when a solder dipped wire is used in fixed compression connections.
Note: Wire where each strand is individually tinned with solder from the vendor is different and works fine in compression connections.