Copper -- 29

08/28/2015 IEWC

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Copper: The Red Metal. Conductor. 29 electrons.

All other available conductors out there, including silver (expensive), aluminum (hard), and nickel (resistant), have attributes that make them fine for special applications, but they do not dominate the wire and cable industry (well, aluminum sure makes a run at it!) quite like copper.

So why copper? Why not aluminum? Why not water… or iron?

It all comes down to a few reasons:

  • It has 29 electrons. Not 28, and not 30. 29 is a great number.
  • It is plentiful. Or at least plentiful enough to use inexpensively.
  • It bends, twists, stretches and can take a beating.

The chemistry of copper is actually really cool (if you like chemistry). The three elements in Group 11 of the Periodic Table are copper, silver, and gold, all of which are excellent conductive metals. In fact, silver is referred to as the best conductor for both electricity and heat. (If you ever go to a dinner party and are served soup, and the soup spoon in your hand heats up very quickly, then you know it is made with silver and not a stainless steel look alike.)

An even tastier example of conductivity would be a Moscow Mule, a combination of ginger beer and vodka, always served with ice in a copper cup. It is extremely cold because the copper cup conducts the cold (or heat, if you prefer) so well—especially to your hand.

Gold is also routinely used as a conductor on many electronic parts in your computer, plated in micrometers, because it conducts so well and is extremely corrosion resistant.

Copper, silver, and gold all have one thing in common. Each element has one electron hanging in the outer orbital all by itself. Copper has one loner in the fourth orbital, silver has one in the fifth orbital and gold has one in the sixth orbital. One lonely electron, far away from all of the other electrons buzzing around the nucleus. One electron just looking for some action…

When you induce electricity, whether it is walking in stocking feet across a carpet and touching a doorknob or running an alternator in your car, that one lonely electron in the copper conductor gets excited and wants to bump into its friendly electron in the copper molecule next to it, transferring its energy to its friend. The friend finds another friend, and the energy is transferred down the conductor until it discharges (like when you grab that doorknob) or until it completes the circuit. These collisions at the electron level are what we call electricity—the flow of electrical energy. The special thing about copper is that the single electron is very good at giving off energy just as quickly as it receives it simply because it is so isolated from the rest of the molecule. Put another way, that electron does not put up any resistance to electrical energy passing through it.

Elements 28 and 30, nickel and zinc, also conduct electricity, but not nearly as well as copper. 29 is the magic number.

Copper has been with us for centuries; a copper pendant was found in Iraq dating back to 8700 BC. Copper is present in Turkey, in Mexico, in the Philippines, in the USA, and very much so in Chile. Its presence in so many parts of the world makes it relatively plentiful and therefore inexpensive to mine, process, shape, and sell. I had said that silver is the better conductor, which is true, but its scarcity makes it so expensive that copper is the preferred metal for the vast majority of conductors.

You must remember, too, that copper has great ductility. It can be shaped; it is malleable. It is soft and can be stretched without breaking. If you’ve seen copper being drawn in a wire mill, it is essentially being stretched like a rubber band—pulled and pulled without breaking—until the proper size is achieved. By the way, this ductility characteristic is also related to the 29th electron. It’s all chemistry—just ask Heisenberg on Breaking Bad.

There are more conductors to talk about: aluminum, silver, and thermocouple bi-metals to name a few. But for now, the red metal has that special group of characteristics that makes it the perfect conductor for the cable industry.