What exactly does cable description describe?

you've found 10mm twin core which has a 4mm earth within

cable is specified by detailing the cross sectional area of the current carrying conductors - so 2.5 actually refers to a 2.5mm CSA of the conductors within

 

Your skip cable is a 10mm² Earth. A standard and recent sized cable.

² Symbol. It is 10mm squared. Cables are measured by cross sectional area.  The insulation and sheathing is not taken into account in any measurements.

 

Hi Trofim
Just to calrify.
2.5mm squared   is  an annotation which means that the round conductor has an 'Equivalent' cross sectional area of 2.5 square millimeters of copper.


A ' cross section' is a section formed by a plane cutting through an object, usually at right angles to an axis.  So if your were looking at a cylinder the CS would indeed be the diameter.  The AREA would be different.

Does this help ?
RS

PS
stop crawling around skips !

 

The 2.5mm refers to the cross sectional area of the live and neutral wires individually. Both these are 2.5mm sq. I think the earth wire will be either 1.5mm sq or even 1mm sq.

The formula for working out the area of a circle is Pi xR squared where R = the radius. For your example of 2.5mm twin and earth, the effective diameter of the live and neutral cables are approximately 0.9mm

 

Hi Trofim

No that isn't quite right.  It is the cross sectional area of the face of the conductor.

Hope that helps.

Kind regards

BS

 

I overheard a discussion in a DIY shed a few years ago where the knowledgeable assistant was carefully explaining to a customer that the reference to the size of a cable in mm2 was measured across the width of the sheath. Thus, the 10mm2 he was asking for to be used on a shower circuit was 2.5mm2 as measured across the width of the sheath. I wonder if the shower ever caught fire.

 

Its frightening how little people know and understand yet try to bullsh1t there way through isn't it?  And to think that this is barely scratching the surface.

Kind regards

BS

 

Kinnel!  :'(


Ya not wrong there Bazza! 

 

You're nnot getting there, lol.

2.5mm/sq is the area of the live OR neutral. The earth on this size cable is typically 1.5mm/sq.

For a perfectly cylindrical conductor, think about ² (Pi r squared). Half the diameter of the conductor, times it by itself, times it by Pi (3.14).  This gives the area (CSA).  Only works for perfectly "round" conductors though.

 

....or square ones!

 

"Hi Trofim
Just to calrify.
2.5mm squared is an annotation which means that the round conductor has an 'Equivalent' cross sectional area of 2.5 square millimeters of copper."

Nope.

Mr. HandyAndy - Really

 

..........or whatever material the cable conductor is made from.............but for the purposes of this topic I have all assumed Mr Trofin was referring to standard cables found in domestic premises..........Go ahead, Mr Handy...make my day !
RS

 

2.5mm squared is 2.5mm X 2.5mm = 6.25 sq.mm.

2.5mm­² is 2.5mm x 1mm = 2.5 sq.mm. (square millimetres not millimetres squared)

Mr. HandyAndy - Really

 

;-)

 

Quite right Andy Pandy.
2.5mm2    is    2.5 square mm .......and the "D" makes all the difference.
Quick typing and the abuse of tramadol can have serious maths consequenses.
RS

 

I'd like to see the look on a sparks face when his gaffer told him he's be first fixing some 2.5cm squared cables.