Top 6 Difference Between Copper and Aluminium Cables

Aluminium Cable Vs Copper cable 

What is Cable?

The cable is nothing but a piece of equipment which is used to connecting two or more electric circuit from one source feeder to destination feeder. The cables are transferring electricity between the circuit.

In industry we use four types of cables; they are aluminium cable, copper cable, silver cable, silver cable. In this article, we are going to see the difference between aluminium and copper cables.

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Technical Difference Between Aluminium and copper cables

  1. The atomic number of Aluminium is 13 and the atomic structure is 2,8,3. In this, we have 3 free electronics in the valance band with three energy level. During the current flow to push valance electrons, aluminium consumes more energy since valance electron very near to the nucleus. Due to this instant, the resistivity of the aluminium conductor is high; typically, 2.65 to 2.82 × 10−8 Ω·m. Therefore, power loss in the AL conductor is high.
  2. In copper, the atomic number is 29 and the structure is 2,8,18,1. Copper is having 4 energy level, hence the attraction from the nucleus to valance electron will be less. Due to this, for pushing the valance electron at the 4th level is simple. That’s why the resistivity of the copper is 1.72 x 10-8 Ωm. Hence power losses in the copper conductor is less as compared with AL conductor.
  3. Atomic Number: 13 (Al) < 29 (Cu) < 47 (Ag) < 79 (Au).
  4. Energy level: 6 (Au) > 5 (Ag) > 4 (Cu) > 3 (Al).
  5. Resistivity: Aluminium > Gold > Copper > Sliver .
  6. Power losses: Aluminium > Gold > Copper > Sliver.
  7. Metal Availability: Aluminium is the earth 3rd abduct material. Hence, the material availability concern Aluminium > Copper > Sliver > Gold.
  8. At the same time, AL is to have a less atomic number which is an advantage for us. The weight of the aluminium is less as compared with another conductor. i.e Al is lighter and the density of the aluminium is 2.7 g/cm³. One cubic centimetre of Al weight is 2.7g. In the case of copper, the density is 8.96 g/cm³. Therefore, based on density: Gold > Silver > Copper > Aluminium.
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Commercial Difference Between Copper and Aluminium cables

  1. Low cost

Pure aluminium is cost around 500 INR (9$) per KG but pure copper rate is 1000 INR per KG. Example:

Aluminium Copper
Size Cost per meter Current carrying Cost per meter Current carrying Make
3C X 2.5 sqmm 12 14 32 22 RPG
3C X 10 sqmm 28 36 96 50 RPG

Table:1

Instead of purchasing 2.5 sqmm copper cable you can purchase 10 sqmm aluminium cable

The cost concern Aluminium is cheap. Aluminium < Copper < Silver < Gold

  1. Flexibility for cable connection:

You can connect it easily at the power terminal. It does not require as much strength to bend the cable.

  1. Less cable termination cost:

Aluminium lugs are cheaper than copper lugs and Easy to crimp. Before crimping any cable (more than 50 sqmm) use crimping paste, which gives good contact between the cable and lug. Using of hydraulic crimping tools gives better result than hand crimping tools.

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Also see: How to Crimp a cable in proper way

Here you can find the rate difference. Actually this is MRP only, you can negotiate with them.

  1. Less weight:

Aluminium has less weight as compare with copper. It does not require as much man power to lay a cable. Always it does not require double compression cable gland.

double compression cable gland
double compression cable gland
  1. Easy available

Due to its easy availability, manufacture will complete you order very faster.

  1. Extended life

Corrosion and moisture free

Disadvantage of aluminium cable:

High power loss

High I^2 X R loss due to high resistivity, R=pL/A => increase in resistivity leads to increase in resistance of the cable.

Less current carrying capacity, low conductivity.

  1. Occupy more space: Due to low current capacity we need to increase the quantity. (lay additional cables
  2. Squeezing

Advantage of copper cable:

  1. Less power loss (low resistivity)
  2. High current carrying capacity (high conductivity)
  3. Occupy less space

Disadvantage of copper cable:

  • High cost
  • High cost for cable termination
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As said in table

  • Cable lugs needs additional tin coating to avoid moisture effect.
  • More man power is required.

Current Carrying Capacity of Aluminium and Copper Cable:

How to avoid cable failure:

  1. Cables should not load more than 50 % of its full load capacity.
  2. Avoid underground cable laying, go for overhead cable laying.
  3. If underground is the only one option means, make proper cable trench/channel.
  4. Avoid water in the cable trenches. 90% of the cables would be failure due to this problem.Pore it periodically.
  5. For long distance if length is more than 50 meter then better you go for armored type cable.
  6. Do not allow to pass heavy vehicles on the cable which damage the cable insulation, make proper shielding while crossing the road/street. Here you can find how to repair cable insulation failure
  7. Use XLPE cable for overhead high surrounding temperature (eg. Near furnace, super heater coils outlet header, feed pump, hp heater etc.)
  8. Purchase better quality.  (RPG > Finolex > Polycab > Paragon)
  1. Use HT nut and bolt (use 8.8 T +)
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How to select cable:

  1. For feeder work (indoor) select flexible copper multi stand cable.
  2. For outdoor work select armored copper/aluminium stand cable

How to select cable lug:

  • For screw type connection use pin type lugs
  • For nut bolt type connection use ring type lugs
  • Use better quality
  • Choose high connecting surface area. (Dowel > Johnson)
  • Use high thickness lugs (Johnson > dowel)

Conclusion:

While purchasing cables please look at these points..

Also see:

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