choosing cable voltage rating

[andrel]

Hi, for a single phase LV installation, how do you determine whether to use 450V/750V or 0.6/1kV cable. Thanks

 

[telectrix]

you select cable so as the rated voltage is higher than the actual voltage of the installation. no point in using 1kV rated cable on a 415/240V installation when 450V rated is compliant.

 

[pc1966]

Also you might find that certain styles of cable are only available in the higher voltage rating.

There is nothing wrong with using the higher rating as such, but it can cost more and lead to larger cables to wrangle.

 

[andrel]

you select cable so as the rated voltage is higher than the actual voltage of the installation. no point in using 1kV rated cable on a 415/240V installation when 450V rated is compliant.

I agree, it seems obvious and yet much of the cable sold installed in Australia is 0.6/1kV. I'm trying to understand why this when 450/750 appears suitable?

 

[Lucien Nunes]

A mechanically robust cable will usually have thicker, stronger insulation than a lightweight one, which allows it to be rated for higher voltages. There would be no point marketing a range of similar cables rated only for the lower voltage range, as the saving in material that could be achieved without diminishing the general capabilities of the cable would be minimal. OTOH Where small size and low cost are important the insulation is reduced and the voltage rating must be lowered to suit.

 

[andrel]

@Lucien Nunes I think that's the answer. I've just noticed that the 0.6/1kV standard (AS5000.1) includes armour. I appreciate everyone's help. Thanks