In article , Scott M
writes

To join the cables, two bits of heatshrink, one large, one small. Cut
the conductors 1cm apart (ie stagger the joins.) Large heatshrink pushed
over both conductors, small on one only - not doing both reduces the
bulge at the join. Big bit of heatshrink covers both joins.

Solder jointing would be my approach too, yes to the staggering although
use of heatshrink on the inner cores can be problematic for the
inexperienced (shrinking the sleeve whilst soldering in close
proximity). A plain sleeve on the inner may be easier and it will be
well held by the outer heatshrink or no inner sleeve at all if the
stagger is long enough to avoid any risk of shorting. A spare bit of
outer cable sheath or a few turns of tape (my pref self amalg) will
match the bulk of the join to the outer of the original before applying
the outer heatshrink.

Also, best to make the join at least 6" from the plug as flexibility
will be reduced at the join.

Alternatively, split the cases on the psus and swap the leads over. Take
some care in rebuilding the strain relief on the cable, they're usually
moulded on the cable and sod's law dictates that they will be different.
--
fred
it's a ba-na-na . . . .