I don’t think it is normal wire it must be graded in some way to blow like a fuse why they didn’t use a fuse I don’t know!
it was about 10yrs ago when I did mine so I would definitely say they are no longer available and can remember trying to find information on them then with no success, if you google fusible link wire there’s info about it but what size or rating you need maybe someone else will be able to put you in the right direction or a possible alternative solution.