Material constant for Tinned copper

Hello subinmathewg

If you are really designing an electrical substation, your basic knowledge is sadly lacking.

"Tinned Copper" is copper which has been tin-plated during manufacture.

"Annealed Copper" is copper which has been heated to "cherry red" then suddenly quenched in water during manufacture.

Other than that, most of the properties are effectively identical.

Tinned copper is used in salt-laden air, where the tin coating prevents quick corrosion of the copper conductor.

Properties of copper may be found on many webpages, using Internet Engine Search term: "properties of copper" (note the quote marks please)

Example: Google Results 1 - 10 of about 720,000 for "properties of Copper". (0.24 seconds)- here are a couple of useful ones:

http://www.unr.edu/sb204/geology/props.html

http://www.copper.org/resources/properties/homepage.html

Have a read of those, and learn about copper.

Use of an Internet Search Engine is going to save much of your non-refundable life-span - they are easy to use, and free.

If you are still needing further advice, reply here please.

Kind Regards....

Sparkstation,

Are you sure of annealing process described by you? The process explained by you seems to be more of a hardening process to me. In annealing you do not suddenly quench but allow the temperature to fall very slowly depending upon the desired "softness" required.

I will also check on - annealing, in case it is different for copper.

Hello capri

That way of annealing the copper was what we used over 50 years ago.

Copper is hardened by being worked.

I would think those principles still hold.

Your <"....The process explained by you seems to be more of a hardening process to me. In annealing you do not suddenly quench but allow the temperature to fall very slowly depending upon the desired "softness" required...."> do not work for copper at all, although they do for some other metals.

Have a look here: http://www.steamengine.com.au/index.php/ic/faq/142-annealing-softening-copper and elsewhere.

Kind Regards....

I am definitely wiser now.

Thank you

It's certainly the way to go for pure copper - unlike iron, copper requires quite large excursions before you see significant work-hardening, and it does not harden noticeably when you quench it. In addition, high-temperature water immersion appears to remove oxides and other contaminants from the surface (I think it actually reduces the copper-oxide, but I wouldn't swear to that).

However, I'd be very cautious about this if the copper is tinned, because there can be all sorts of alloying interactions. I have a feeling that very short anneal times are used for coated copper, but again it's outside my area of expertise.

FYI...

Applicable Standards for Earthing

a) IEEE std 80,575,

b) IEC 60621-2,

c) BS 5345,6651,7430.

Material Constants of tinned copper

Where

Material constants of a particular conductor are required to size the conductor inorder to withstand the System fault level.

Subin

Don't come to sudden conclusions,Who can estimate the power of a human being..Have a nice day

Hello subinmathewg:

Can you tell me the Town you are installing this electrical transformer,.................so I can stay away?

http://www.webelements.com/copper/

This site pretty much tells you most if not all about everything on the Periodic Table. Thi link takes you straight to [CU] Copper.

Menting point: 1357.77 [or 1084.62 °C (1984.32 °F)] K

Electrical resistivity: 1.7 10^-8 Ω m; or mΩ cm

• Thermal conductivity: 400 W m^-1 K^-1
• Coefficient of linear thermal expansion: 16.5 x 10^-6 K^-1
• Element properties
• Physics properties: Boiling point; melting point; density; molar volume; thermal conductivity; and electrical resistivity; bulk modulus; critical temperature; superconductivity temperature; hardness (mineralogical, Brinell, and Vickers); linear expansion coefficient; Poisson's ratio; reflectivity; refractive index; rigidity modulus; Young's modulus; velocity of sound
• Images
• Reactions of copper: reactions of copper with air; water; halogens; acids; and bases
• Crystal structure
• Thermochemistry: enthalpies of atomization, fusion, and vaporization;
• thermodynamic properties
This site also has this animated list which goes through the temperatures and gives its physical properties.
• Animate the above image by quicktime movie
• Animate the above image by animated gif
Take care and good luck!

Answering your question: the main reason for using annealed copper is to take advantage of its mechanical properties (ductility or "softness"). As stated by other respondents, resistivity, thermal conductivity/capacity and fusion temperature are unchanged. The fact that you ask questions 1 and 6 separately sets alarm bells ringing - so be sure that you have your design checked and signed off by an experienced and qualified engineer.

Returning to the reason for annealing: if the tinned copper is being used for earth lines that need to be bent around the substation, it is important that you use material that is specified as annealed and that has not previously been bent away from its as-supplied condition.

Actually, the resistance of copper goes up as it is cold worked, therefore annealed copper has the best conductivity. But tinning the copper should make absolutely no difference.

On a somewhat off-topic note: It has become exceedingly apparent to me that the meaning of the word "engineer" in the US, Canada, the UK, and Down Under is very different from the meaning assigned in India, Pakistan, and other places. I'm not trying to insult anyone, I'm only trying to make sure that everyone is on the same page. an engineer in India and Pakistan and Indonesia, at least a newly minted one who has no field experience, is basically a trade school graduate and was not given a strong theoretical education. They were taught how to cookbook an existing design, not how to design from first principles. Older engineers who have been in industry for a while often learn how to suppliment this education with real world experience, but a newly minted engineer does not have experience to fall back on. This is a distinction that many people (especially managers in chage of "offshoring") fail to make, to their ultimate dismay/chagrin. Also in that part of the world, product liability is not that big a deal. Personal Injury/Product Liability Lawyers apparently have not discovered that part of the world yet. So there is not the same safety culture/fear of litigation driving the credentialing of engineering professionals the way there is in the US and the UK.

Dear 'Engineers',

It is pretty good to read the replies which is mostly weighing the knowledge of me.Sadly telling no one gave specific response to my question.No one qoute from which Electrical standard I can get the values.Even no one replied which IEEE it is.Thanks for the 'Links' and 'Analysis' about me.I understood that who all replied didn't do the Earthing calculation before.

Hello Guest,

We have no way of knowing if you are the Original Poster.

It is normally expected that people at least attempt to do some research, before asking for answers here at .

If you do your own research, or at least attempt it, instead of expecting others to do the "donkey work" for you, you will learn new skills, remember what you find, and improve your own permanent personal knowledge base.

Replying to Topics which may be Homework or Class assignments: Refer to CR4 FAQ as against the Rules, although sometimes helpful answers are given by generous souls.

For those reasons you may have received some of the advice and answers above.

I trust that explains the situation for you.

Kind Regards....

Hello Sparky,

I echo your your condiments in the OP's direction..........

How can someone so inept (being honest) get to even think about building or designing an electrical system like a transformer? It really beggars belief! Glad I am nowhere near the locale.

I wonder if he/she realises that perhaps if they need to ask advice, they should never be in that job in the first place?

Take care Sparky.............

Hello Guest,

Sadly telling no one gave specific response to my question.No one qoute from which Electrical standard I can get the values.

If you are the Original Poster (OP)...........

Your post is # 7. In the previous 6 posts.......In posts by Sparkstation #'s 1&6, by me babybear in post # 2, and in post 4 by Rorschach, there was considerable help given. In a post after yours, in post 13 there is at least three detailed ref' to standards used which you asked for. However, you failed to come back ans respond in a positive way to anyone! I do not think you are even the original poster.

The whole idea of posting back and forth is to help people and for them to tell us what they have learned or some sort of history, so future readers can glean some help from these posts.

If you are still visiting and are the original poster please reply to some of the positive posts.. Or are you just a time waster?

I tell you what, you got it lightly compared to my first question. I was accused of all kinds of illegal actions! That is a fact! But I did not give up. I came back and answered the questioning for several hours until at last someone believed me.

I personally spent about three hours trying to help and, I know others must have spent at least similar times to me in helping and, all we are worth for our unpaid effort is a big fat sillence! That is really sad.

Take care and as I do not know to whom I am speaking I cannot insult you can I?

Hello subinmathewg:

I posted details and advice to go to the link I put on post #2. This seems to have all the details you want or most.

Please talk a look including the 'Flash' of the element getting gradually hotter and what happens to them.

Please let me know what you think.

Sorry everybody is ripping you apart man. I'm sure you have knowledge in the subject of substations, and this is more of a material science problem. How did this problem of selection arise?

Tinned copper will have a different properties, but I'm guessing the wire you are using for a substation is soo thick you don't have to worry about the tin thickness when figuring out some of these properties. Tin and copper do have a reaction between them, and over time the tin will diffuse further into the copper to form a solid solution. Again, if your wire is big enough (not some tiny speaker wire) this thickness shouldn't be substantial in changing copper's properties. The amount of annealing of annealed wire will also change properties.

Now is the question of the purity and amount previous heat treatments that went into the copper (Tinned copper is just annealed copper with a coating). This is given by a IACS percent (International Annealed Copper Standard).

YOU WILL NEED THIS VALUE to determine the resistivity and requires experiments to determine. This IACS value is the fraction of the wires resistivity compared to a 100% pure single crystal of copper. So, if you have 85% IACS wire you need to do some calculations with the material properties of 100% IACS copper…

Resistivity at 20C: 10.37 Ohm m

So, the resistivity of 85% IACS wire is 8.81 Ohm m

The question you asked had 6 parts, but resistivity and conductivity are one in the same. Resistivity is the reciprocal of conductivity. Reciprocal is just 1/X, so from resistivity of 100%IACS is 10.37 the conductivity is 1/10.37= 0.0964 at 20C. The same goes for the thermal coefficient of resistivity and this is just the reciprocal of the thermal coefficient of conductivity.

You will need to get the IACS from the manufacturer and it should come when you purchase the wire. The specific heat, coefficient of thermal resistivity, and fusing temperature of pure copper are

Thermal coefficient of resistivity at 20C for 100%IACS: +0.00393 Ohm m / C

Specific Heat: 0.385 kJ / Kg C

Fusing Temp: 1083C

These values may be different for different IACS wires (IACS is not just from different anneals but also impurities), but these require difficult experiments to determine. If you need the exact values you will need to contact the manufacturer, and if they don't have the values just use these for pure copper. If you really need the exact values and the manufacturer doesn't have them, and nobody in the world has them, but you still really need them you are out of luck because these experiments are difficult and require good setups to be accurate. This answers your six questions.

Hello wild idea,

Immense pleasure to say a thanks for your valuable reply.I got the values from IEEE.Your reply gave good clarity on the same.

And to everybody who commented by basically making fun of people, the problem is really complex but many of the variables can be removed by their insignificance. Somebody stated the weakness of other countries engineers, but by complicating a simple question you have all shown the weakness in more theoretical engineers.

Hello Wild Idea:

I hope you are well...................

Talking about whatever help I could give and have given and, any assumed insults............

Two of my Uncles are Electrical Engineers and fit at least one sub-station every other year, (roughly). They in general do not work on domestic dwellings, they are 'Industrial' Electrical Engineers I guess you could say.

The first two jobs working with the 'big stuff', Grid Transformers had to be financed by mortgaging their homes. I am telling you this to show they were and are fully professional Engineers...............That said, there is no way either of them would be about to start a job, or part way through it, and ask advice on ANY ASPECT of their chosen profession.

Domestic Electric can kill one or two people if all is not right. Power and sub stations can possibly kill many more, especially if they explode.

My comments, and others can comment if they wish, were made in disbelief that someone thinking about this build of a power sub station, should not know his chosen profession in more detail!

I certainly was not making fun of anyone. And spent a couple of hours trying to find the details he requested, and posted those details.

My bad, sorry for the bad energy.