What Makes Copper the Best Conductor for Wires?

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SUMMARY

Copper is widely recognized as the best conductor for wires due to its balance of cost, conductivity, and ductility. While silver is the best conductor, followed by copper and gold, aluminum is often used for its lower cost despite its disadvantages in residential wiring. The National Electric Code (NEC) allows aluminum alloy conductors for branch-circuit wiring, but its poor thermal expansion properties can lead to loose connections and potential fire hazards. Understanding the properties of these metals is crucial for selecting the appropriate conductor for specific applications.

PREREQUISITES
  • Basic understanding of electrical conductivity
  • Familiarity with the National Electric Code (NEC)
  • Knowledge of metal properties, specifically copper, aluminum, and silver
  • Awareness of wiring applications and safety standards
NEXT STEPS
  • Research the properties of AA-8000 series aluminum alloy conductors
  • Learn about the thermal expansion characteristics of different metals
  • Study the implications of oxidation on electrical conductivity
  • Explore the advantages of using gold in electronic connections
USEFUL FOR

This discussion is beneficial for electrical engineers, electricians, and students interested in understanding the properties and applications of different conductive materials in wiring systems.

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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