British cables association reediee wiring matters

?	OUTBUILDINGS

In this article, we will consider the

requirements when supplying a detached

At the end of the article we will discuss:

■ what to do if the garage has an extraneous- conductive-part such as a metal water pipe
■ verifying the existing installation, including the assessment of the earthing and bonding
arrangements
■ protection of the cables, and
■ inspection, testing and certification.

■ An RCBO in the dwelling’s consumer unit for the garage supply, or
■ An RCCB in the dwelling’s consumer unit, or■ Selecting a device that includes RCD protection as

IEE Wiring Matters | Autumn 2005 | www.iee.org

■ Protecting the socket-outlet circuit in

��	��	■	the garage with an RCBO, or
��	��	■

(fig 2).

��	��	If the ring final circuit is suitable for the
��	��	additional load, the garage could be supplied
		from a fused spur inserted in the ring and a
		cable run out to the socket-outlet in the

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OUTBUILDINGS

��	��	10mm2main bonding conductor would be
		required to connect the water pipe in the
		garage with the Main Earthing Terminal in

the rating and condition of existing
equipment, including that of the distributor,

	��	should be adequate for the additional load
	��	and that the existing earthing and bonding

second option (above) was adopted.

Protection of the cables
The cable run from the house to the garage must be suitably protected either by being run overhead (see Regulation 412-05-01) or buried in the ground (Regulation 522-06-03 refers). Where cables are installed in areas inhabited by rodents, such as might be
found in a garage, the wiring system must

gnawing (Regulation 522-10-01).

Inspection, testing and certification
Inspection and testing must be performed to confirm the adequacy of the relevant parts of the existing installation, which will
support the changed requirements, the
upgrading of the existing installation
necessary to support the addition or
alteration, and the addition or alteration
itself. The requirements for initial verifi-
cation are contained in Chapter 71 of BS 7671 and further information on the requirements for inspection and testing is given in the IEE Publication Guidance Note 3 Inspection and Testing. Compliance with BS 7671 must be verified for every addition or alteration
(Regulation 721-01-02 refers). Requirements for certification and reporting in respect of electrical installations are given in Chapter 74. An Electrical Installation Certificate
must be provided to the owner of the instal-lation giving details of the extent of the
installation covered by the certificate, with a record of the inspection and the results of the testing (Regulations 741-01-01 and 743-01-01). ■