Each issue, the ECA’s Technical Services department answers a selection of members’ most frequently asked questions – providing expert guidance and tips. This issue, the focus is on electrical installation work
Electrical installations
Q|How close to a sink or basin can a minimum distance for socket outlets
socket be located? A|BS7671:2008 does not specify any
to be sited from a sink. Regulation 512.2.1 requires external influences to be considered when selecting equipment for a particular location.
The regulation requires all equipment to be of a design appropriate for the situation in which it is to be used. Sockets that are used in domestic installations are not splash resistant, so are therefore not suitable for installation close to any sink or draining board. It is recommended that socket outlets and other accessories should be located at least 300mm, measured horizontally, from a sink or draining board, where they are unlikely to be splashed.
Q|Can I certify other contractors’ work persons scheme?
if I am a member of a competent A|No. Members of Part P Competent Persons Schemes can only certify the
compliance with the Building Regulations of their own work, or work in which they have had a substantial involvement. Note that a person competent in electrical
inspection and testing may be prepared to electrically certify that an electrical installation, including DIY work, complies with BS7671. However, electrical certification of compliance with BS7671 (IEE Wiring Regulations), which are non-statutory, is not at all the same as certification of compliance with the Building Regulations, which are statutory. You should check what is required by the relevant local authority building control (LABC) department.
64 ECA Today July 2011
Q|Does the connection of equipment, require notification?
such as cookers, boilers and so on,
A|No. Connection of equipment to an Q|Can I install a new spur from
a special location or kitchen.
an existing circuit without being registered on a competent persons scheme?
A|Approved Document P of the Building Regulations gives general guidance on
work that is not notifiable to building control bodies on pages 8 and 9, tables 1 and 2, plus additional notes. If the scope of works falls within the
constraints of work that need not be notified, it can be carried out by a person not registered to a scheme, but the installation must still comply to BS7671:2008 and a Minor Electrical Installation Works Certificate must be issued.
A|Yes, for compliance to BS7671:2008. If the cable is a PVC insulated and
Q|Do I need to provide protection for cables buried in walls?
sheathed cable, installed at a depth of 50mm or less from the finished surface, either horizontally or vertically from an accessory or within 150mm of a wall-to-wall corner, or within 150mm of the wall to a ceiling, then this will require additional protection against impact damage and nail penetration, by a 30mA RCD. If the cable is protected within a conduit
or trunking, or is an armoured cable, MICC cable or cable manufactured to BS5836, then this will exempt the cable from requiring additional RCD protection against impact damage and nail penetration.
existing point is not notifiable, even in Cable capping is not considered to provide
adequate protection. However, if conduit and trunking are to be used, it must be noted that chasing out masonry can create problems in complying with the Building Regulations Approved Document A.
Q|Where pipework in a bathroom is radiator and so on?
plastic, do I need to bond the bath,
A|Where the main pipework of water distribution and central heating
systems are PVC, short sections of pipe connecting taps, radiators and the like are not considered to be extraneous conductive parts, because they are unlikely to introduce earths to the location. Supplementary bonding is, therefore, not required.
Q|Do I need RCD protection on a shower circuit?
A|Yes. See BS7671:2008, Section 701 – Locations containing a bath
or shower. The scope covers any location containing a fixed bath (bath tub) or shower. Additional protection by 30mA RCDs is required for all circuits serving equipment in the location. A single RCD may protect a group of circuits, but must take account of the consequences of unwanted tripping.
Q|Do I need to provide supplementary bonding in a commercial kitchen?
A|Supplementary bonding of metal work surfaces is not a specific requirement of
BS7671:2008. However, the designer of the electrical installation may perceive there to be an increased shock risk and specify ‘additional protection: supplementary equipotential bonding’. Regulation 411.3.2.6 states that where automatic disconnection cannot be
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