NEC on soldering wiring

On 27 Sep 2006 21:03:00 GMT, snipped-for-privacy@ipal.net wrote:


Properly made up in a wirenut it won't heat up at all. Bear in mind 14, 12 and 10 ga already have the 125% built into 240.4(D).
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On Wed, 27 Sep 2006 21:37:41 -0400 snipped-for-privacy@aol.com wrote: | On 27 Sep 2006 21:03:00 GMT, snipped-for-privacy@ipal.net wrote: | |>Just how hot will such a twisted and capped connection get with the 125% |>level of current flow? | | Properly made up in a wirenut it won't heat up at all. | Bear in mind 14, 12 and 10 ga already have the 125% built into | 240.4(D).
I'm not really concerned about the wire gauge specifically. What I am concerned about is the contact cross section, and how loose it will be in 20 years.
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| Phil Howard KA9WGN (ka9wgn.ham.org) / Do not send to the address below |
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jaw,
You seem to be describing a hand held "spot" welder. The "jaws" are the ONE TURN secondary of a transformer (like the old solder guns) and when where is sufficient pressure the primary circuit will draw 10 amps (@120). The "several amps" can be on the order of 50 to 100 amps.
Years ago we used them to weld thermocouples or put filaments onto headers. In these applications the "subject wire" had a much higher resistivity than the copper jaws.
That said, I surprised you can make effective welds on copper. I would think you would as likely weld the copper wire to the jaws! I guess the size of the jaws keep them from melting.
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It is akin to a spot welder, but smaller. It doesn't melt the base material/copper like a welder does. It just heats it up enough to melt the solder you apply. The 'jaws' are much smaller about the size of small pliers. Because the current is lower and the temperature of the copper never approaches melting, it doesn't stick to the jaws at all.
Other than that, yes you have the idea. Heats up the wire nice and quick to make soldering the dozens of joints in a motor go fairly quickly (once you have them mechanically made up).
daestrom
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I had a wire nut connect fail OPEN. It was in a house that had been vacant for about a year. When the power came back on the connection "worked" for a few months and then one day it was OPEN.
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Well, as others have shown, there are all sorts of details.
Sometimes solder is okay, but sometimes it can actually make the situation worse. Solder is generally softer than copper so with mechanical fittings it 'squeezes' out of the connection and loosens the connection over time.
Best answer is always, use listed devices/components and install in accordance with the manufacturer's instructions. Generally, that means do *not* solder wires used in wire-nuts. Over in alt.engineering.electrical there are also a lot of dicussions about this and the other often-asked question, "Should you twist the wires together before installing the wire-nut?"
daestrom
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Well that was stupid, this *IS* alt.engineering.electrical. Look in the archives here and see the various opinions.
daestrom
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