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6
HAVELLS
Under the 17th edition wiring regulations:
Note: Each circuit may have more than one reason for additional
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a socket outlet and secondly because of the cable installation
method. Additional protection is provided as additional protection.
It does not obviate the need for circuit protection by circuit breakers
or fuses.
* Regulation 411.3.3 socket outlets with a rated current not
exceeding 20 A that are for general use by ordinary persons
(exemption may be permitted).
** Regulation 701.411.3.3 additional protection shall be provided for
all circuits of the location by use of one or more 30 mA RCD.
*** Regulations 522.6.6 522.6.7 522.6.8 cables concealed in a
wall or partition at less than 50 mm depth and without earthed
mechanical protection e.g. conduit.
**** Regulation 314.1 Every installation shall be divided into circuits
as necessary to avoid danger and inconvenience in the event of
a fault, take account of danger that may arise from the failure of
a single circuit such as a lighting circuit, reduce the possibility of
unwanted tripping of RCDs etc.
**** Regulation 314.2 Separate circuits to be provided for parts of
the installation that need to be separately controlled in such a way
that those circuits are not affected by the failure of other circuits.
***** Regulation 560.7.1 Chapter 56 circuits for safety services shall
be independent of other circuits.
****** Regulation 443 Risk assessment for control of transient
overvoltages (surges) and where appropriate, selection and
installation of surge protectors (in accordance with Section 534).
In addition Chapter 51 requires designers/installers to take account
of all relevant British Standards and manufacturers instructions. For
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alarm systems in dwellings. It states that power supplies to Grade D
smoke alarms should be an independent circuit at the consumer unit,
or a separately electrically protected local lighting circuit.
British Standards and IET regulations are subject to change
and amendments. This guide to Havells consumer units is
not a substitute for the regulations which should always
be used for all types of electrical installation design and
installation work.
Summary Table
Regulation Relating to
Examples
Additional Protection
411.3.3
Sockets up to 20A
rating for general use by
ordinary persons
Upstairs Sockets, Downstairs Sockets,
Kitchen Sockets, Cooker outlet with integral
13A socket, Garage Sockets, Plus any other
sockets up to 20A rated
30 mA RCD
701.411.3.3
All circuits in a room with
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Shower circuit, Lighting circuit, Heating circuit
Ventilation circuit, Shaver Socket, Plus other
circuits
30 mA RCD
522.6.6
522.6.7
522.6.8
All circuits buried in a
wall or partition at less
than 50 mm and without
mechanical protection
Downstairs Lighting, Upstairs Lighting,
Immersion Heater, Burglar Alarm, Smoke
Alarms, plus any other circuits
30 mA RCD
q All socket outlets should be protected by 30 mA RCD
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high rise apartment block*
q KK BHQBTHSR HM @ QNNL VHSG @ jWDC A@SG NQ RGNVDQ RGNTKC AD
protected by one or more 30 mA RCDs**
q All cables buried beneath the plaster surface of a wall or
partition (at less than 50 mm) should be protected by 30
mA RCDs***
q All cables concealed in metal stud partitions (common in
new builds) should be protected by 30 mA RCDs***
q Installations should be divided up into circuits so as to
take account of danger and inconvenience caused by a
single fault - e.g. such as a lighting circuit ****
q Installations should be designed and arranged so as to
prevent unwanted tripping of RCDs****
q Safety services such as smoke alarms should be on
independent circuits*****
q Sensitive electrical equipment installed in the home may
require protection against overvoltages (surges), where
these overvoltages would exceed the equipment’s with
stand voltage