On Tue, 12 Sep 2017 11:17:08 +0100
John Rumm wrote:

You can probably
choose to pull just a single wire, or to fold the wire back and
attach the other end to the puller as well, so that you pull a loop
(this doubles the pulling power, at the expense of halving the pull
speed)

While mine can be rigged for single cable pulling (that's how I used
it in the application I bought it for) it's clearly not designed to be
used that way. When used as designed the tension in the fixed side of
the cable holds the frame straight, but with that side disconnected it
really needs a better guide to control the cable - the flimsy guide
that is fitted won't last long with the angle that the cable runs in
single cable mode.