Cable Size???

whazza22 · May 22, 2010

Is there a tool or way or determing the size of a cable if you have no information? (eg. 25mm earth)

Sometimes it can be tricky to know the size of a cable by looking at it.

Guest123 · May 22, 2010

A lot of guys carry off cuts of different sized cables in the van for comparison with cables you come accross on jobs. Helps to identify sizes.

m4tty · May 22, 2010

That's a good idea lenny cheers. Other than that you could use a micrometer

johnboy6083 · May 22, 2010

a micrometer wont tell you the CSA of a cable. you could work it out on a round conductor, but i dont know about shaped conductors. I like Lenny's idea though. Also a lot of cables have the size written/stamped on the sheath.

ezzzekiel · May 22, 2010

I find cable clips help a 6mm clip fits a 6mm cable snug etc

Notsosmart · May 22, 2010

Or lugs (if the cable isn't terminated)

Smugley · May 22, 2010

If you've got access to the bare conductor you can use a caliper to measure the diameter. Divide by 2 to get the radius (r).
The CSA is approximately pi x r squared.
Of course stranded cable should be rounded down a bit.

whazza22 · May 23, 2010

Thanks for the replys.

I mainly need to know when im carrying out a Periodic Inspection on commericial/industrial buildings and do not after access to bare conductors.

Many of them have no markings on the sheath either.

Most of the cables range from 16-50mm

Sintra · May 23, 2010

This table has overall diameter for BS 5467 SWA cable.

No. cores x csa / Nominal overall diameter mm

2 x 1.5 / 12.1
2 x 2.5 / 13.6
2 x 4.0 / 14.7
2 x 6.0 / 15.9
2 x 10.0 / 18.0
2 x 16.0 / 20.4
2 x 25.0 / 20.4
2 x 35.0 / 23.3
2 x 50.0 / 25.8
2 x 70.0 / 29.0
2 x 95.0 / 33.1

3 x 1.5 / 12.6
3 x 2.5 / 14.1
3 x 4.0 / 15.3
3 x 6.0 / 16.6
3 x 10.0 / 19.5
3 x 16.0 / 21.6
3 x 25.0 / 25.5
3 x 35.0 / 28.0
3 x 50.0 / 28.5
3 x 70.0 / 32.2
3 x 95.0 / 37.0
3 x 120.0 / 40.4

4 x 1.5 / 13.5
4 x 2.5 / 15.0
4 x 4.0 / 16.0
4 x 6.0 / 18.7
4 x 10.0 / 21.1
4 x 16.0 / 22.9
4 x 25.0 / 27.6
4 x 35.0 / 30.4
4 x 50.0 / 32.0
4 x 70.0 / 37.7
4 x 95.0 / 41.7
4 x 120.0 / 47.1