As the moderator of a Freecycle group I can say that we always allow
electrial items to be offered on Freecycle. It's exactly what Freecycle
does best - allowing people to avoid putting goods in landfill when they
can be used again or utilised for spare parts. I've given away a number
of electrical items on Freecycle - strimmer, hedge trimmer, chainsaw.
If you know of a defect you should point it out, of course. But you
aren't offering any warranty or guarantee, and if it develops a fault
later, you won't be liable unless you failed to disclose a fault that
was known to you.
I suppose there's a slight chance that someone would sue you in the
belief that you had concealed your knowledge of a dangerous defect. A
court would then have to hear the evidence and decide whether to believe
you, and that would involve legal costs. If that worries you, you'll
probably not want to give any electrical tools away or lend them to anyone.