Does coating stranded copper wire with solder cause any issues or break any codes?

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Does coating stranded copper wire with solder and then connecting it to a standard outlet cause any issues or break any codes?
I have a small project I put together (this is all inside of a big box ... ie: not inside a wall or part of the house ... but I still would like to make sure it's safe and meets any code requirements as if it was inside a wall or part of the house) which uses stranded copper wire (14AWG). I coated the ends with solder and then bend them to shape before connecting them to standard outlets (screwed on, not the push in). Will this cause any problems or break any electrical codes (I'm located in Ontario, Canada in case that matters).
The reason why I'm asking is because I've been doing a whole bunch of reading about issues with aluminum wire, one of the issues being the thermal expansion problems caused by the aluminum wire expanding at a different rate than the screw connector it's connected to on an outlet/switch/etc. So this made me wonder if the solder will cause any problems with thermal expansion of it being different than the screw that it's screwed on to, etc.?
Thanks for any info you share, Harry
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back before the advent of 'solid state' and 'Printed circuit boards' all electronics, even high power devices, used copper wires that were 'tinned' with solder before being attached to screw terminal strips. it was the 'professional way of doing it.
as an electronics guy, I still 'tin' all wires I'm going to be soldering.
"tinning" means putting a coating of heated solder over the bare wire PRIOR to making the final solder connection.

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FireBrick wrote:

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Gave us:

A "tinned" wire that is done that way by the manufacturer is different than tinning wires at your bench or via a solder pot.
For one thing, the manufactured tinned wire has no lead in the PLATING (co-valent), and said plating is very uniform and very thin.
A tinned wire at the bench has lead in it, IS susceptible to solder creep, and the process is intermetallic, but only when done right.
Placing said wire in a PCB, the proper way to prep the wire is the way you describe. For it to be pre-tinned as it is called. The MAIN reason is so that one can construct the PCB / wire / solder joint connection in the fastest time frame, reducing the likelihood for insulation damage to a minimum. It also increases the odds of constructing a proper solder joint with the highest reliability and least amount of leeching of the solder up the wire, in the case of stranded wire.
The discussion, however, is about whether or not a wire inserted into a crimp type solderless connector should be soldered, and whether or not such a termination preparation is an accepted practice by the industry engineers and manufacturers, not necessarily at the assembler or inspector level.
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could not solder the wire to the outlet because the screw fell off. Using solder for convenience, as you have, is fine. I usually crimp fittings on stranded wire.
Now, your box project is suspect; but you didn't ask about that.
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You should not solder stranded wire prior to putting it into a screw terminal. Solder creeps under pressure, so the contact pressure will steadily reduce over time until it forms a bad contact. Strands which are tinned during the cable manufacture are OK, as the solder layer thickness is controlled and very thin. I'm not familiar with your local regulations, but in cases of stranded wire connecting to terminations which don't work well with stranded wire, the normal method is to crimp on a bootlace ferrule or an eyelet, depending on the terminal style.
--
Andrew Gabriel

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Andrew Gabriel ( snipped-for-privacy@cucumber.demon.co.uk) said...

The only place I ever use stranded wire with screw terminals is in a lamp, and I have on occasion tinned the end first.
I find the creep problem very bad and screws and stranded wire are a bad mix. I have had a few instances where #14 or #12 stranded wire was pulled through a conduit, so instead of trying to attach it to a screw terminal, I would pigtail a short piece of solid wire to it and attach it to the terminal.

That reminds me of a lecture I once attended. The speaker was telling of an experience with a company he was working with back in the 1960s when they got a project related to the space program. They all had to be "schooled" in procedures such as soldering, which seemed beneath them at the time.
The thing that stuck out in my mind was part of NASA's standards: when a stranded wire was tinned or soldered to a terminal, you should still be able to count how many strands it has.
--
Calvin Henry-Cotnam
"Never ascribe to malice what can equally be explained by incompetence."
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said...

Reminds me of ET-Maintenance school in the military. Spent literally a *week* learning/practicing on just how to solder to bi-furcated and turret terminals.
We too had to be able to count the strands after tinning. And how much insulation to strip off so that no more than 2 mm of conductor was exposed after attaching to terminal. And no melted insulation, and... and... and... There was something like 14 checks for each soldered terminal connection.
Was bad enough on the bench, but then doing it laying on your back reaching up inside a cabinet with just a drop-light to see by. Now *that* was fun (NOT!!!).
daestrom
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daestrom wrote:

everything steady while soldering upside down with arms reached up to the work and hoped you were good enough not to burn yourself.
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Calvin Henry-Cotnam wrote:

working with a defense contractor, was really hard. Their standards are very tough, for a good reason of course.
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Calvin Henry-Cotnam wrote:

The electric service panel in my house has long stranded ground wire held in two places by bolts. I dont think its tinned though. It is silver but I suppose it comes from the drop that way.
--
Thank you,



"Then said I, Wisdom [is] better than strength: nevertheless the poor
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said...

Is there any reason to consider tinning the ends when fixing through a screw terminal? The surface area of contact would be increased at the contact I suppose, and thereby increase the area of contact for the passage of electrons, but the cables should never be used *at capacity*. Next thought is on how the crimped terminals of the wires lose area of contact for passage of electrons and hence the heat evolved on the lines at the terminal(s) increases as a proportion borne on each line. Hence consideration would lead me to increase cable sizes and design cable sizes for the terminals; the specifications being based upon the surface area made at the fixing and the heat I would wish to allow there.

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On Sun, 5 Feb 2006 14:19:41 -0000, "Billy H"

On a soldered wire, it would be due to solder creep.
http://en.wikipedia.org/wiki/Creep_%28deformation%29

In a proper connection, the heat rise is only a few degrees more than that produced in the conductor itself. If there is an excessive differential between the heat in a conductor, and the heat generated at a connection node, then the connection either has a problem, or is not of a sufficient capacity for the current in the circuit.
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writes: : > Does coating stranded copper wire with solder and then connecting it to : > a standard outlet cause any issues or break any codes? : > : > I have a small project I put together (this is all inside of a big box : > ... ie: not inside a wall or part of the house ... but I still would : > like to make sure it's safe and meets any code requirements as if it : > was inside a wall or part of the house) which uses stranded copper wire : > (14AWG). I coated the ends with solder and then bend them to shape : > before connecting them to standard outlets (screwed on, not the push : > in). Will this cause any problems or break any electrical codes (I'm : > located in Ontario, Canada in case that matters). : > : > The reason why I'm asking is because I've been doing a whole bunch of : > reading about issues with aluminum wire, one of the issues being the : > thermal expansion problems caused by the aluminum wire expanding at a : > different rate than the screw connector it's connected to on an : > outlet/switch/etc. So this made me wonder if the solder will cause any : > problems with thermal expansion of it being different than the screw : > that it's screwed on to, etc.? : : You should not solder stranded wire prior to putting it into : a screw terminal. Solder creeps under pressure, so the contact : pressure will steadily reduce over time until it forms a bad : contact. Strands which are tinned during the cable manufacture : are OK, as the solder layer thickness is controlled and very thin. : I'm not familiar with your local regulations, but in cases of : stranded wire connecting to terminations which don't work well : with stranded wire, the normal method is to crimp on a bootlace : ferrule or an eyelet, depending on the terminal style. : : -- : Andrew Gabriel
I know that, at least on Ottawa, and I imagine most places, you cannot tin wires to be used where an electrical inspecation is necessary. Same in the states. No, I cannot cite NEC, so no use asking. The reasons are exactly as Andrew pointed out. Solder compresses and deforms to whatever force is applied to it and as soon as air creeps in, there is corrosion, moisture, etc etc etc., not to mention the affects of vibrations, etc.. How do I know? I got to see a connection that failed, then started to heat (high currents) and the solder dripped out of the connection onto the wireing below it. No, it's not a horror story, but the melted solder wasn't too cute inside the box. Whoever installed it didn't know the first thing about tinning, besides it not being acceptable to do; he had the wiring well "blobbed" with sodler<g>. I think I understand why you want to tin it, but properly dressed stranded wire will work perfectly under appropriate screw heads. If it's a permanent install, I'd modify it accordingly, again along the lines of Andrew's suggestions. He's right on.
Pop
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Pop wrote:

My father used crimped connections on all his wiring on his house, then soldered and taped (no wire nuts, was done in 1970) All still works great. At time when having to replace an outlet or light switch, everthing was still pretty solid, but do intend on doing a preety thorough inspection soon including junction boxes in the attic.
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writes:

That's a good idea. The problem of lost contact area is assuaged somewhat by the fact of coating the wire and the terminal with solder. Other problems inside the connection are negated.

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On Sun, 5 Feb 2006 14:22:28 -0000, "Billy H"

Not necessarily.

Crimped connections using the proper wire size, and connector do not "lose contact area".

What problems? Done correctly, the area of contact is gas tight.
That still does not negate the fact that it is outside the spec for the terminal lug to add solder to it.
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message writes:

I am in the industrial controls business and work with stranded wire extensively, especially finely stranded wire in challenging environments. It is almost pervasively common that manufacturers supply equipment with the wire ends dipped in solder, I have never seen those loosen to any degree more than non soldered ends,
the soldered ends seem to be much more reliable and preferred. Thats after 40 years in the business across a broad spectrum of industrial applications, nuclear, petrochemical, semiconductor, food and marine applications.... including DDC applications.
Crimp connectors also work. they are less reliable than factory or field soldered ends under a screw in marine or industrial corrosive environments however.
Phil Scott

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The code says you can't make a connection that depends entirely on solder. It has to be a compression connection. Screws, bolting, clamping crimping etc. It's O.K. to solder after it's tight. I have heard of failed inspections because someone tinned stranded wire, then secured it in a solderless lug. The reasoning being that if it gets hot, the solder flows out, and it is then loose.That may be debatable, but I lean toward agreement on it.
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Long Ranger wrote:

that solid wires can stil be twisted then soldered as was the practice before wirenuts appeared.
---------------------- If tightly twisted wire was minimally tinned I would think the solder would hold the strands in place and the stress of clamping would be borne almost entirely by the copper. Do you still get cold flow?
bud--
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