Systems for use with Renewable Energy
Relevant Regulations 2
FELV must not exceed 50 V r.m.s, A.C., or 120V ripple free D.C.
411-01-01
If an extra-low voltage supply is used, but does not comply
with all the regulations for SELV, then to provide protection against electric
shock, the appropriate requirements of Regulations
471-14-02 to 471-14-06 shall be complied with. 471-14-01, 411-03
The fact that the voltage is extra-low voltage shall not be
used as the only means of protection against electric shock.
411-01-02
Protection against direct and indirect contact
Where the regulations for SELV are complied with, except that live or exposed
conductive parts are connected to earth, or to the protective conductors of
other systems, then protection against direct and indirect contact is afforded
providing:
1. Enclosures give protection against the insertion of a solid body that exceeds
12mm in diameter, and up to 80mm long. (IP2X)
2. The insulation withstands a test voltage of 500V r.m.s, A.C., for one minute.
If the equivalent degree of safety is provided by equipment conforming to
a relevant British Standard is installed or used, the above requirement shall
not exclude its installation being carried out without supplementary protection.
471-14-02
Where the extra-low voltage system does not comply with the
regulations for SELV, other than by live or exposed conductive parts being
in contact with earth or protective conductors of other systems, then protection
against direct contact shall be provided either by one or more of the following:
1. Barriers or enclosures complying with the regulations
412-03001 to 04.
2. Insulation corresponding to the minimum test voltage required for the primary
circuit. Where the extra-low voltage circuit supplies equipment whose insulation
does not comply with the minimum test voltage required for the primary circuit,
then any insulation which is accessible shall be reinforced during erection
to withstand a test voltage of 1500 V r.m.s. A.C. for one minute.
471-14-03
Protection against indirect contact
Where the primary circuit of the source of extra-low voltage is protected
by automatic disconnection of the supply, then exposed conductive parts of
the extra-low voltage system shall be connected to the primary circuit protective
conductor.
471-14-04
Where the primary circuit of the source of supply for the FELV
is protected by electrical separation, then the exposed conductive parts of
the FELV circuit shall be connected to the primary circuit’s non-earthed
protective conductor.
471-14-05
Barriers or enclosures
Live parts shall be in enclosures or behind barriers giving protection against
direct contact, giving minimum protection against the insertion of a solid
body exceeding 12 mm in diameter and up to 80mm in length. (IP2X). Where an
opening larger than this is necessary for the
replacement of parts, or to avoid interference with the functioning of the
equipment, then both the following requirements shall be met.
1. Unintentional contact with the live parts shall be prevented.
2. Provision shall be made so that a person is sure to be aware that live
parts can be touched through the opening, and that they should not be touched.
A larger opening than IP2X is only allowed for equipment or accessories complying
with British Standards, where it is impractical to contain the opening to
IP2X, due to the function of the equipment, e.g. a lampholder. Where such
a deviation is used, the opening shall be as small as possible.
412-03-01, 471-05-02
Where horizontal top surfaces of barriers or enclosures are
readily accessible, then it must not be possible to make contact with live
parts with small tools, wires or other thin objects which are more than 1mm
thick (IP4X).
412-03-02
Barriers or enclosures shall be suitable for the normal working
conditions to which they will be subjected in service, and be firmly secured
in place, to provide stability and durability in order to maintain the degree
of separation and protection required.
412-03-03
Where it is necessary to remove a barrier or to open an enclosure,
then one of the following precautions has to be taken:
1. Opening an enclosure or removing a barrier must only be possible by using
a key or tool, or
2. It must only be possible to open an enclosure or remove a barrier after
the supply is disconnected, and it must only be possible to restore the supply
after the barrier has been replaced, or the unit reclosed, or
3. An intermediate barrier giving a degree of protection of at least IP2x
is installed to prevent contact with live parts.
The above does not apply to BS 67 ceiling roses, BS 3676 cord operated switches,
BS 5042 B.C. lampholders or to BS 6776 E.S. lampholders.
412-03-04
