ABB ESP M1R Installation Instructions Manual page 30

If possible the two units should be connected to the
power supply a short distance apart either:
(a) onto the first two outgoing ways
(b) up to a metre apart on the incoming power supply
9.5 Installing three phase units on single phase supplies
If a three phase unit is installed on a single phase mains
supply (or a supply in which one or two phases are not in
use), the ESP units spare (or unused) live terminal(s)
should be connected to live, otherwise its indication
lights and volt free contact will not work correctly. The
preferred approach is to take a connecting lead from
each spare terminal to the supply live. However, it is also
possible to connect the ESP units spare terminal(s) to
whichever live terminal is in use at the unit.
9.6 Use of powered screwdrivers
The use of powered screwdrivers is not recommended
unless measures are taken to ensure screws are
tightened correctly and not damaged
9/3 | Installation instructions for mains wire-in protectors