Insulation

[Akash Kagi]

Hello,

Though the questions that I post in this Homework help section are actually not related to my homework but appear in my 9th STD physics text book with the label "Think It Over", I feel it is appropriate to post them here, because even after much thinking I have not been able to find right explanation.

The question is- "The aluminium wires used in the transmission of electric current are not insulated. Why?"

Thanks.

Edited December 26, 2010 by Akash Kagi

[swansont]

What are your thoughts? What is the purpose of insulation, and why might one not insulate aluminum?

[TonyMcC]

Are the aluminium wires allowed to touch each other - what might that imply?

[random]

Seems to me you will need to give yourself a history lesson into the installation methods of knob and tube wiring which was non insulated aluminum wire and ceramic holders to support the wire. Modern aluminum wire is insulated.

 

nope scratch that i was second guessing myself and for good reason KT wiring wasn't aluminum KT wiring came earlier and was insulated though poorly.

 

share your answer when you get it because I cannot find a single reference of any aluminum wire ever being installed uninsulated.

 

except for overhead power lines so perhaps we're looking for the wrong answer

[TonyMcC]

Seems to me you will need to give yourself a history lesson into the installation methods of knob and tube wiring which was non insulated aluminum wire and ceramic holders to support the wire. Modern aluminum wire is insulated.

 

nope scratch that i was second guessing myself and for good reason KT wiring wasn't aluminum KT wiring came earlier and was insulated though poorly.

 

share your answer when you get it because I cannot find a single reference of any aluminum wire ever being installed uninsulated.

 

except for overhead power lines so perhaps we're looking for the wrong answer

Although I have never seen it used in practice the following link explains what the original question might have been getting at http://en.wikipedia.org/wiki/Electrical_wiring

Look under Aluminium Conductors.

In fact it seems that what happens is more of a problem than a benefit!

[Spidey]

Hello,

Though the questions that I post in this Homework help section are actually not related to my homework but appear in my 9th STD physics text book with the label "Think It Over", I feel it is appropriate to post them here, because even after much thinking I have not been able to find right explanation.

The question is- "The aluminium wires used in the transmission of electric current are not insulated. Why?"

Thanks.

 

 

Hello,

I got into the same question when I was studying in 9th STD and I am still looking for the answer. Please tell me the answer if you get it.

[Nexium Tao]

Hello,

I got into the same question when I was studying in 9th STD and I am still looking for the answer. Please tell me the answer if you get it.

 

Spidey, think of it this way. Why would you need to insulate something? then the logical continuiation of that would be, why would you need to insulate copper? You figure that out, then you have figured out that whatever shortcoming copped has that requires insulation, that aluminum just doesn't have.

[Spidey]

Spidey, think of it this way. Why would you need to insulate something? then the logical continuiation of that would be, why would you need to insulate copper? You figure that out, then you have figured out that whatever shortcoming copped has that requires insulation, that aluminum just doesn't have.

 

 

Can you repeat it once again clearly. I am confused.

[swansont]

I think he was basically repeating what I said earlier

 

 

What is the purpose of insulation, and why might one not insulate aluminum?

[ewmon]

Today's students have the world's knowledge at their fingertips. I googled aluminium wires not insulated, and the answer appeared in the first entry on the google results page (without even clicking on the link!) --

 

Unlike copper, aluminum forms an insulating oxide layer on the surface

[Nexium Tao]

Today's students have the world's knowledge at their fingertips. I googled aluminium wires not insulated, and the answer appeared in the first entry on the google results page (without even clicking on the link!) --

 

 

 

I don't think you are allowed to actually answer the question, only point him in the right direction. That is why we were posing questions to him, to help him realise logically why aluminum doesn't need to be insulated, instead of just telling him why.

 

 

Homework Help Rules

A simple reminder to all: this is the "Homework Help" forum, not the "Homework Answers" forum. We will not do your work for you, only point you in the right direction. Posts that do give you the answers may be deleted.

 

Edited December 27, 2010 by Nexium Tao

[michel123456]

I don't think you are allowed to actually answer the question, only point him in the right direction. That is why we were posing questions to him, to help him realise logically why aluminum doesn't need to be insulated, instead of just telling him why.

 

It is not the answer. Now the pupil must prove that a 4 nm thick layer of oxide is enough insulation for 220V electric current.

[ewmon]

Nexium Tao, thanks for the reminder. I did spell it out, but Tony had led Akash Kagi to the Aluminum conductors section in Wikipedia's article on Electrical wiring, which says the same thing.

 

I also think it's dangerous for a modern textbook to suggest that bare aluminum conductors are safe. I agree with Random because I also have not heard of uninsulated aluminum wiring.

[swansont]

Nexium Tao, thanks for the reminder. I did spell it out, but Tony had led Akash Kagi to the Aluminum conductors section in Wikipedia's article on Electrical wiring, which says the same thing.

 

I also think it's dangerous for a modern textbook to suggest that bare aluminum conductors are safe. I agree with Random because I also have not heard of uninsulated aluminum wiring.

 

Conductors used in transmission are not quite the same as "wiring," in the way that the terms are usually used.

[random]

I think the question refers to aluminum wire used in the transmission of high voltage current in power lines. There is nothing to even consider using uninsulated aluminum wire in a residential or light industrial setting as safe.