... whether you make a small 'nik' in a few peripheral conductor strands doesn't matter, because 99.99% of uses for wire on a boat (except battery connections) are sized for acceptable voltage drop over the total length; not limit of amp carrying capacity. The fuse will (should) blow before the wire size is an issue. Also, if you have a half-inch of smaller diameter in a long run of larger diameter, the voltage drop of the larger diameter rules. So I think it's OK in most cases to be missing a couple of strands at the connector.

(Donning fireproof suit.)