If this is the main generator output wire, replace it, period. And as Harold has suggested, make sure the replacement wire is re-routed, clamped, etc to protect against future damage.
Why replace the wire rather than use crimp splices to repair it? Crimp splices are pretty good, but will never be as good as the original stranded wire. Plus at each crimp you have an opportunity for a high-resistance connection to either be made by poor crimping, or to build up over time as a result of corrosion.
It's work to replace a wire, but not nearly as much work as rebuilding your airplane after an electrical fire. If you have to use a crimp connection to "tide you over" until you have time to do the job right, then that's what you have to do, but in the end you should replace the entire wire in order to ensure maximum integrity and longevity of your aircraft electrical system.