ABB ESP M1R Installation Instructions Manual page 15

Outgoing ways internal to the building
Incoming supply
Outgoing way
internal to the
building
On small, compact, metal cased distribution boards,
(such as small MCB boards) the first way is preferable,
although any outgoing way is suitable.
On a large board such as a cubicle switchboard, it is
better to install the protector on the load side of the
incoming isolator
(eg in the metering section) for optimal protection.
(iii)
Installation instructions for mains wire-in protectors | 3/8
Outgoing way
to external load
directly to the busbars via suitable HRC
fuses, switch fuses or MCCBs - see Section
3.7.
Figure 7:
Connection for supplies
continuing external to
the building.