Originally Posted By: rmoore This post was automatically imported from our archived forum.
Am I right that these are copper conductors “tinned” to prevent corrosion? At first glance I thought I had solid aluminum, but given the age of the home (1920’s) that didn’t make much sense. By pressing my nose against the main bus bars (kidding) I could just see a copper core.
![](upload://9Tri7QVFiGa5KAPc7X8N8bqiziz.jpeg)
Second question...what is the time period when solid aluminum wiring was in use?
-- Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com
Originally Posted By: Bob Badger This post was automatically imported from our archived forum.
I have heard 3 explanations for tinned copper.
1)Corrosion as mentioned.
2)Something to do with the old style insulation.
3)To aid in soldering connections.
I do not know the answer.
The corrosion answer 1 does not make sense to me as we do not tin copper now and it does not corrode.
The insulation one I never understood.
My gut feeling is # 3 for soldering in the time frame you see tinned conductors you also see soldered electrical splices, a pretinned conductor will solder much faster.
Originally Posted By: phinsperger This post was automatically imported from our archived forum.
Richard,
Yes those are tin coated copper wires and I applaud you for noticing and not reporting aluminum ![eusa_clap.gif](upload://vwXJP6EroRUgatgS660IOyuD5XK.gif) I have tin coated copper wires in my house (all with soldered connections) and I am in the middle of replacing all of them. Partly because too many people look at it an think its aluminum.
Originally Posted By: rmoore This post was automatically imported from our archived forum.
Bob Badger wrote:
we do not tin copper now and it does not corrode.
Bob...I know they do still tin stranded copper wiring for marine applications. I realize that is a much more corrosive environment, but perhaps they just didn't have the good residential "history" back then?
You might be right on the soldering though...I was just assuming the corrosion thing.
-- Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com
Originally Posted By: rmoore This post was automatically imported from our archived forum.
I just dug out my big Fisheries Supply book (I built and wired the interior of a commercial trawler a few years back). The tinning, at least for marine applications, is “to prevent corrosion and electrolysis”.
Maybe there was an "exterior" or "multi-purpose" grade of the old wiring?
-- Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com
Originally Posted By: jpeck This post was automatically imported from our archived forum.
If I remember correctly (man, that was a long, long time ago), the tinned copper was because of the rubber insulation.
It also aided in soldering because all connections were soldered back then.
The problem with tinned copper is not the copper, or the tinning, but with the rubber insulation. I has all dried out, is cracking, and is (in most cases) electrically useless (sure it 'protects the conductor, but so does the cloth wrap, cracked insulation is considered failed insulation).
There is but one solution when you have rubber insulation on the conductors and aluminum wiring - re-wire.[/list]
Originally Posted By: phinsperger This post was automatically imported from our archived forum.
jpeck wrote:
The problem with tinned copper is not the copper, or the tinning, but with the rubber insulation.
Very true Jerry, the rubber on the tin coated copper wiring I am replacing is hard as a rock in the boxes above the ceiling light fixtures. It must be from the heat of the light over the years that has dryed it out. The rest of the wire is still flexible at this point.
Originally Posted By: rking This post was automatically imported from our archived forum.
Tin coated copper??
I was taught, and always call it 'aluminum coated copper". That is what my reference book refers to as well.
If it is indeed tin coated can anyone provide me with an online or downloadable reference??
I include information in print form with my reports like this, and aluminum wiring, oil tanks & lines, GFCI protection etc as a courtesy to my clients for their info.
-- Muskoka Home Inspections
"Wisdom is the Anticipation of the Consequences"
Steering Committee Member At Large
Originally Posted By: roconnor This post was automatically imported from our archived forum.
I spec tinned copper for bare buried ground loop wires on communication facilities (usually solid tinned copper #2 leads and stranded tinned copper #1/0 ring).
Bare copper forms an oxidized layer on the outside that does not give the wire good conductivity ... not good for grounding systems trying to dissipate surges from things like lightening strikes on a tower.
-- Robert O'Connor, PE
Eagle Engineering ?
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NACHI Education Committee
I am absolutely amazed sometimes by how much thought goes into doing things wrong
Originally Posted By: rmoore This post was automatically imported from our archived forum.
As this is still active I thought I would post part of a PM I received a few days ago from a forum member I’m familiar with but who didn’t wish to post it himself.
Quote:
I researched this topic a while back. The insulation on the old wiring was hygroscopic and 02 permeable, the resulting infusion of water and air did cause corrosive problems.
The first and foremost reason for the tinning was to aid in soldering..it could be left exposed for quite some time and still soldered w/o any cleaning. Severe environment tinned wire can still be bought, but modern insulations have made the use of it in residential applications unnecessary.
Makes perfect sense to me. Bob B. was right on all three counts...(I guess we all were in a way). ![icon_biggrin.gif](upload://iKNGSw3qcRIEmXySa8gItY6Gczg.gif)
(1) It's an anti-corrosive due (2) to the insulation, added (3) as an aid to soldering.
-- Richard Moore
Rest Assured Inspection Services
Seattle, WA
www.rainspect.com
Originally Posted By: Bob Badger This post was automatically imported from our archived forum.
The more I learn about the ‘old time’ methods the more respect I have for them.
I have never come across a soldered wire connection that went bad.
The old methods did very well with the materials available to them.
I have taken out old BX that the insulation was perfect inside the armor, the problem is mostly at light fixtures that have been over lamped and baked the old stuff.