Needknow? to
Each issue, the ECA’s Technical Services department answers a selection of members’ most frequently asked questions – providing expert guidance and tips for contractors
Q| Where flats are fed individually from sub-mains originating at a
main intake position, and the gas and water services are main bonded at the main intake position, do we still need to provide main bonding in each of the flats?
A| Main protective bonding is required Q| Can accessories and electrical equipment such as socket-outlets
and under-cupboard lighting be fixed to fitted kitchen units?
A|Yes, provided that they are securely fixed to rigid parts of the units that
are not demountable or otherwise liable to be disturbed in normal service. However, care must be taken to comply with all the relevant requirements of BS 7671, including accessibility for inspection, testing and maintenance, and provision of adequate protection against damage (by impact or water for example) for the accessories, equipment and associated wiring. Regulation 530.4.2 is not intended to preclude such common practice. This is intended to be clarified in the 17th Edition in due course.
partitions less than 50mm deep need to be protected with a 30mA RCD?
Q| Do meter tails concealed in walls or
A|Additional protection for meter tails by means of a 30mA RCD
is not an acceptable option in respect of Regulation 522.6.6 and 522.6.7. Concealing of meter tails in this way needs to be avoided, if this is really not possible one of the other methods must be used, for example, mechanical protection sufficient to stop nail/screw penetration.
62 ECA Today March 2011
Q| Do domestic boilers and heating equipotential bonding?
Q| When a Grade D fire detection pipework need to have additional
A|Providing there is adequate continuity between the boiler/pipework and the
Main Protective Bonding there should be no need for any further bonding to the boiler and pipework, unless it is in a bath/shower room and all the circuits of the location are not additionally protected by a 30mA RCD. However, supplementary bonding may be required in the boiler manufacturer’s instructions.
and alarm system to BS 5839-
6: 2004 is protected by an RCD, should the RCD operate independently of any circuits supplying socket-outlets or portable equipment?
A|There are no particular requirements or limitations in BS 5839-6
concerning the use of RCDs with Grade D fire detection and alarm systems. For Grade D systems, which comprise one or more mains-powered smoke alarms each with an integral standby power (such as typical domestic smoke alarm with battery),
at the main intake position; it is also
considered good practice to provide main protective bonding in each flat even though, as in this case, the origin of each installation could be considered to be at the main intake position.
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