# B How does the current carrying capacity depends on thickness

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1. Mar 12, 2016

### Anshul J 2016

How does the current carrying capacity depends on the thickness of insulation of conductor ?

2. Mar 12, 2016

### davenn

What physical thing happens to a wire carrying current ?

When you insulate that current carrying wire, what then happens to the wire ?

and if the insulation is even thicker ?

As a side hint ... think about why insulation is put around a hot water pipe in parts of countries with cold climates ..... what does that insulation achieve ?

Dave

3. Mar 13, 2016

### davenn

so what are your thoughts ?
can you think of some answers to those Q's

Dave

4. Mar 13, 2016

### Anshul J 2016

First of all Thanks for those questions which are in turn helping me to ponder about the answer of my question..

My views on your questions asked are as -

1. Physical thing - Heating effect is produced in wire carrying current due to resistance..
2.When we insulate the wire, wire gets protected from outside temperature and heat generated inside the wire gets dissipated through insulation ( if insulation thickness is equal or less than critical radius.)
3. If insulation thickness is increases beyond the critical thickness than heat transfer decreases to surrounding.
4. In cold countries hot water pipes are insulated to prevent the loss of heat from water to outside where temperature is low and thus reducing the heat loss.

5. Mar 13, 2016

### davenn

Yes
no, you are looking at it the wrong way around ... if the wire has insulation on it, the heat cant escape as easily

yes, but for any thickness

yes, so you see how that is bad for a wire carrying current
the overall effect is ... The insulation will cause the wire to heat up more, and as the temperature of the wire increases,
it's ability to carry current decreases. All very significant in circumstances where high current is a factor

you might find this an interesting read ....
http://www.ieee802.org/3/poep_study/public/sep05/walling_2_0905.pdf

cheers
Dave