What Makes Copper the Best Conductor for Wires?

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Discussion Overview

The discussion revolves around the properties of copper as a conductor for wires, comparing it with other metals like silver, gold, and aluminum. Participants explore various factors such as cost, conductivity, and practical applications in wiring, including building codes and safety considerations.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants assert that copper is widely used for wires due to its perceived superiority in conductivity and other properties.
  • Others argue that silver and gold are better conductors than copper, questioning the definition of "best" in this context.
  • Aluminum is mentioned as a cheaper alternative that conducts well, but concerns are raised about its legality in house wiring and its performance characteristics.
  • One participant notes that carbon conducts well but has limitations in terms of flexibility.
  • There is a discussion about the historical context of aluminum use in wiring, including references to the National Electric Code and the evolution of aluminum alloy conductors.
  • Some participants provide a ranking of conductors based on conductivity, with silver at the top, followed by copper, gold, and aluminum, while also discussing the effects of oxidation on conductivity.
  • Concerns are raised about the safety of aluminum wiring due to issues with thermal expansion and connection integrity, which can lead to higher resistance and potential fire hazards.

Areas of Agreement / Disagreement

Participants express a range of views on the best conductor for wires, with no consensus reached. There are competing perspectives on the advantages and disadvantages of copper, aluminum, and other materials.

Contextual Notes

Some statements about the legality of aluminum in wiring are clarified, indicating that previous claims may have been overly broad. The discussion also highlights the importance of understanding specific applications and conditions affecting conductor performance.

Who May Find This Useful

This discussion may be of interest to students, educators, and individuals exploring materials science, electrical engineering, and practical applications of conductors in wiring.

Smarty Qauk
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I need some help with my science fair project question and I want to know what metal it is honestly it has to be copper write that is what wires are made of?
 
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If cost is unimportant, silver and gold are better conductors than copper.

But what is your definition of best?
 
well least expensive and a good cunductor
 
Aluminum is cheaper than copper and conducts well, but it is illegal in house wiring in USA building codes.

Edit: Carbon conducts very well, but cheap forms of carbon don't bend well.

Everything has advantages and disadvantages.
 
Okay but something that is use-able cheap and a good conducter.
 
Copper is popular because most people believe it is is best including all properties.
 
Ohhhh ok sounds good thanks
 
If you want a good grade on your project question, work harder of the question rather than looking for answers.
 
ok thank you for the tips but i am only in fourth grade.:smile:thank you
 
  • #10
Smarty Qauk said:
ok thank you for the tips but i am only in fourth grade.:smile:thank you

Fourth grade :eek: I'm impressed. Just remember, a good question is better than 10 answers to a poor question.
 
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  • #11
well i am in fourth grade cats which means we are doing fifth grade sixth grade and fourth grade work maybe some seventh grade but i don't know.:smile::cool::oldlaugh::oldbiggrin::oldsmile:
 
  • #12
anorlunda said:
Aluminum is cheaper than copper and conducts well, but it is illegal in house wiring in USA building codes.

Edit: Carbon conducts very well, but cheap forms of carbon don't bend well.

Everything has advantages and disadvantages.
Actually aluminum is not illegal in the USA. Certainly not as a blanket statement.
 
  • #13
Averagesupernova said:
Actually aluminum is not illegal in the USA. Certainly not as a blanket statement.

You are correct, my statement was overly broad. Here's what I found here. It is an interesting history.

The NEC (National Electric Code) has required aluminum alloy conductors for branch-circuit wiring (12–8 AWG) since 1981. The Code never explicitly prohibited aluminum building wire; however, there was a period in the early 1970s when UL withdrew the listing for aluminum building wire and revised the listing to require aluminum alloy conductors. During this process, there was no listed aluminum building wire available except remaining stock. Today’s “new technology” aluminum building wire is made of AA-8000 series aluminum alloy.
 
  • #14
To correct some misinformation:
Best Normal conductor: Silver
2nd Best: Copper
3rd: Gold
4th: Aluminum

All metals are good conductors (unless oxidized ie rusted or tarnished). Even with a thin coating of oxidation, the metal can conduct if the charges can be induced (put on) the conductor below the oxidation layer ie tarnished silver still conducts electricity well.

Gold is often the preferred conductor for electronics or at least plugs and junction points as it doesn't corrode/tarnish and always has a clean surface (only a few acids have any effect on gold vs all other conductors can rust or tarnish even in air).

Aluminum is light and cheap, but has poor ductile characteristics and dissimilar thermal expansion compared to copper wire which lead to poor connections and installations. The poor connection would form over time, not as initially installed due to the aluminum expanding and contracting under the equipment lugs (screws) as the wire warmed up under current flow. This is similar to someone loosening the screw a quarter turn or more. Loose connections equal higher resistance which in turn equals higher temps equal loosing the lug up more until you have a very poor connection that gets very HOT and a fire ensues! Hence the bad reputation for using Aluminum, especially for branch circuits ie home wiring.
 
  • #15
Aluminium is common in overhead high-voltage cables because of its weight. It is then used with a steel core for strength.
 
  • #16
ok thank you so much for your help
 

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