Work done to move a charge is
(quantity of charge) x (potential difference during the move) .
Notice that the distance doesn't matter ... only the volts of
potential change along the way.
If the route is along an equipotential line, there is no potential
difference, so it doesn't take any work.
Through a conductor, it also doesn't take any work, if the whole
conductor is at the same potential.
That never happens in a real conductor, like a copper wire or a
cable at normal temperature. There's always some potential
difference along the conductor, so it takes some work to move it
through.
BUT ... strange as it may seem ... the so-called 'superconductors',
which are exotic materials at ridiculously low temperatures, have
literally NO resistance. Not just very low, but zero ! If you start
a current flowing in a superconductor material, and then submerge
it in liquid helium at a few degrees above absolute zero, you can
disconnect the battery and connect the ends of the superconductor
together, and as long as you keep it cold, the current continues to
flow around and around in the superconductor, with no loss, for
months or longer ! It sure sounds weird, but this is how they build
the super-strong electromagnets in CT and MRI machines. ((I guess
that's why it costs so much to get a set of 8-by-10 color glossies from
your CT scan. They don't snap 'em with their smartphone.)
