Safe Speed Forums

You make a good point there Pete. The cable construction is far from simple and is often/usually oil filled. So I think this is a theoretical question more than practical.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

100mm^2 or 100 square millimetres means a square of side 10mm. 100 millimetre square means a square of side 100mm or 10,000 square millimetres.
It can a source of confusion and the fact that the original question gets the units for resistivity wrong makes you doubt anything they say.
But there was a rule of thumb - 1.5 amps/mm^2 for ally or 2.5 amps/mm^2 for copper - which suggests that 100 mm^2 is correct.

100mm square is a big expensive cable. Another obvious rule of thumb is that the cost of the lost power should not exceed the cost of servicing the debt incurred to buy and string the cable.

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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
When I see a youth in a motor car I do d.c.brown

Thanks again everyone.

"DCB knows what he's talking about shocker".

Oops - I blame sunlight on the phone screen...

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Driving fast is for a particular time and place, I can do it I just only do it occasionally because I am a gentleman.
- James May

Toltec, who says two wrongs doesn't make a right? Your final answer (for the net resistance) was correct anyway

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Views expressed are personal opinions and are not necessarily shared by the Safe Speed campaign

You can have 100 lines too, you whippersnapper!

I knew the cable is expensive - and pikeys keep nicking it.
Better to put a genny on site!

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Time to take responsibility for our actions.. and don't be afraid of speaking out!

Because they want to know the student can pick out the relevant information and discard the irrelevant.... I guess (or at least that's what I always thought when I did Physics A level).