The "fibre" cable is actually a heating element. The element operates in the same way as a kitchen toaster operates, essentially the same metal ribbon, which uses resistance to heat the metal untill it glows red/white hot which in turn burns the smoke oil. By cutting the wire you have affected the resistance of the length of wire, thus there is a higher chance of it burning out if you used it in its shortened form.

Basically it would be best to replace the whole unit, or try to make contact with S. Perry on this board as he has experience in smoke unit matters.

Hope this helps.

Cheers Mario