LV Cables

Then use British Standard 7671.

You could have done a search of this forum and found this:

https://cr4.globalspec.com/search/sitesearch?do=show&sort=textmatchrank&srch=cable&srchobjs=t%2Cc&fs=12&order=asc

You can search from the internet by just typing 'cable data's' or you can get all the cable specification and the ampere capacity from the cable manufacture.

Even some of the cable trading or suppliers have all the cable ampere capacity printed in their yearly dairy that were given to all the customer.

Or search in this CR4 forum. We have discussed many time and even the list of the cable ampere capacity is found in here.

Certainly, your clients would also like you to know this. In fact, I imagine that your clients assumed that you already knew this when they hired you. Obviously, you do not. That's sad. Sad for you, sad for them and potentially deadly to any unfortunate soul who stumbles across your "work" in the future. I suggest that you consult a real engineer before your inemptitude kills someone of importance (someone other than YOU that is).