Guide to 17th Edition Consumer Units

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Smoke
Shower Sockets Lights Cooker Sockets Lights
Option 5 Split Load Twin RCCB plus Unprotected Circuit
Under the 17th Edition requirements it is
still possible to install some circuits in
domestic premises that are not fed via
an RCD. Different wiring systems would
need to be used. The cost of installation
could rise considerably if most circuits
were installed using armoured cable or
earthed metal conduits.
The smoke alarm circuit could be
installed in such a way to negate the
need for RCD protection, this may be
possible by using one of the other
wiring methods described in 522.6.6 for
the length of run that the cable is in the
wall (use of earthed metal conduit for
example). Or depending on the layout of
the property there maybe an attached
garage for example where surface
wiring might be possible. The
requirements of that regulation are
therefore not applicable.
The level of compliance with the
Regulations would therefore be the
same as option 2 Split Load Twin RCCB
plus Dedicated RCBO.
Guide to | 17th Edition Consumer Units 19
“If the smoke alarm circuit is not to be protected by
an RCD it must be installed using a method from (i) to
(iv) of regulation 522.6.6”