The most important measurement of a cable in regards to crimping is the cross-sectional area of the conductor which is usually measured in mm² within Europe or AWG in cables manufactured in the USA. ...A cross reference of AWG, MCM and mm² wire sizes is in our data and technical section.
If the wire size is not known you can calculate it by squaring the diameter of one of the conductors and then multiplying by the number of conductors. The type or style of cable is also very important. For example the cable entry diameter in a cable lug for a cable designated with a measurement of 10mm² will be 4mm for a solid stranded cable, 4.5mm for a multi-stranded cable and 5.5mm for a fine stranded cable (examples shown are from the Klauke range of tube terminals).
To complicate matters further there are now modern cables with compacted multi-stranded conductors to VDE 0295 Class 2. The conductors in these cables are up to 15% thinner than the conventional type for the same wire size which can cause issues when crimping. If you are using these new compacted cables please see the Klauke BLUE connection section of our website. The other issue is that the stated dimensions and tolerances can vary between different cable manufacturers so it is always advisable to try a sample first.