as faster mentioned, its all about the sheave-a lot of current line can probably handle more tension than other parts of the rig- in any case, if you are doing it yourself (learned the hard way) try to attach the new to the old in a manner that will bring it through the sheave smoothly, as if it gets hung up you are making a trip up the stick or calling a rigger anyhow.
an opened up paperclip with one stripe of elec tape has worked, as well as a portion of solder or a straightened hook from a clothes hanger. be wary of too much tape, it will jam....
in any case, good luck....
nothing worse than seeing two ends of connected line come spiraling down and knowing one has to go back up...
How inappropriate to call this planet Earth when it is quite clearly Ocean ~ Arthur C. Clarke