Roger Mills wrote :
If that is truly the case, it doesn't matter *how* it's connected - but the
OP mentioned having a separate off-peak fuse board

The separate fuse board is simply to make the installation easier. A
time clock sets the on/off times and that (usually) operates a
contactor, the contactor then feeds a separate fuse board. So nothing
at all to stop you using separate clocks, one per heater, other than
the inconvenience of checking/setting several clocks.

--

Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk