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Consumer Unit Arrangements
Option 5
Split Load Twin RCCB plus unprotected circuit
Under the 17
th
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.
An example is shown over page.
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
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