[ Technical: FAQs ]
the front of the cupboard) and it is fi xed to a sturdy part.
Q| Does the requirement for a warning
A|The current wording of 537.2.1.3 is ambiguous and needs to
notice in accordance with Regulation
537.2.1.3 apply to a two-gang light switch fed by two separate circuits in a domestic situation?
be clarifi ed. It is recognised that this requirement may be diffi cult to comply with in some situations.
Q| If a dwelling has an existing
BS 5839-6 simply recommends that the mains supply to the smoke and/or heat alarms should take the form of either: i) an independent circuit at the dwelling’s main distribution board, in which case no other electrical equipment should be connected to the circuit (other than a dedicated monitoring device installed to indicate failure of the mains supply to the smoke and/or heat alarms); or
ii) a separately electrically protected, regularly used local lighting circuit. We recommend option ii) on the grounds that disconnection of the supply to the fi re detection and alarm system will be more readily noticed. In our opinion, ‘separately electrically protected’ does not preclude sharing an RCD with several other circuits where this is permitted by BS 7671.
Q| Are there any particular requirements
relating to the mounting height or location of consumer units for electrical installations in new dwellings?
A|The provision of access to consumer units is not specifi cally covered by
Building Regulations or BS 7671. However, consumer units need to be located so as to enable reasonable access by the users, including for the purpose of testing the RCDs at regular intervals, and in case of emergency. The best advice for anyone working on
new build dwellings intending to install the consumer units at high (above 1400mm) level is to seek clarifi cation from the authority carrying out the building control function what their requirements are.
Q| Is it acceptable to mount a cooker
switch in a kitchen cupboard that is adjacent to the cooking appliance?
A|Yes, provided the switch is located so as to be readily accessible (i.e., near
consumer unit with an integral main
switch, and other circuits are installed using a second consumer unit with an integral main switch, is another ‘main switch’ required to isolate both consumer units simultaneously?
A|Regulation 537.1.4 requires a main linked switch or linked circuit-breaker
to be provided as near as practicable to the origin of every installation as a means of switching the supply on load and as a means of isolation. However, it is permitted for a dwelling to have more than one electrical installation. Therefore a further ‘main switch’ is not required to isolate both consumer units. Regulation 537.2.2.6 requires each device used for isolation to be clearly identifi ed by position or durable marking to indicate the installation it isolates.
Q| Which socket-outlets in commercial
and industrial premises are NOT required to have additional protection by RCD?
A|Socket-outlets in commercial and industrial premises must have
additional protection by means of a 30mA RCD if they are rated at 20A or less and are for general use without the supervision of a skilled or instructed person. An exception is made for a specifi c labelled/identifi ed socket- outlet for a particular item of equipment. The decision as to which socket-
outlets are provided with RCD protection in accordance with these criteria should be made in consultation with the client’s duty holder under the Electricity at Work Regulations 1989.
Any questions?
If you have any questions you’d like answered by ECA Technical Services or require any further information on issues raised here, please contact ECA Technical Services at
robert.plum@
eca.co.uk or call 020 7313 4850.
As a general principle, it may be
considered that socket-outlets in commercial and industrial premises that are not required to have additional protection by means of a 30mA RCD include the following: a socket-outlet labelled for the connection of a specifi c item of equipment; socket- outlets not intended for general use, such as those in fl oor service boxes intended for the connection of workstations and other IT equipment; general use socket outlets that are under the supervision of skilled or instructed persons so as to minimize the possibility of careless use.
Q|What should I do if a consumer unit
I have been asked to replace is in a relatively inaccessible position?
A|You should make your customer aware of the issues relating to
accessibility, including the need to test RCDs at quarterly intervals, to enable the customer to make an informed decision about the position of the replacement consumer unit.
Q|What Recommendation Code should be given if it is found that there is
no supplementary bonding in a bathroom having extraneous- or exposed-conductive- parts, and the conditions given in Regulation 701.415.2 for its omission are not met?
A|Recommendation Code 2. Q|What should I recommend in a
Periodic Inspection Report if I fi nd
that an existing installation still relies for fault protection on a voltage-operated earth- leakage circuit-breaker (VOELCB)?
A| If the VOELCB fails to operate when tested with an instrument or
integral test button, this would warrant a Code 1 recommendation (requires urgent attention).
But, subject to the VOELCB being proved to operate correctly, continued reliance on it for fault protection (protection against indirect contact) would normally warrant a Code 4 recommendation. However, if the VOELCB relies on a water
pipe not permitted by Regulation 542.2.4 to be a means of earthing, this should attract a Code 2 recommendation (requires improvement). The user should be given clear
instructions to test the device at quarterly intervals by means of the integral test button and should also be advised that the voltage- operated device should be replaced with RCD protection at the earliest opportunity to enhance the safety of the installation.
March 2011 ECA Today 63
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