Code of Practice for the Electricity (Wiring) Regulations - 2009 Edition

circuits are electrically separated, the circuit protective conductor is
connected to the exposed conductive parts of the equipment and to
a point of the secondary winding of the transformer or equivalent
device. The protective conductor(s) between the equipment and the
transformer should comply with one of the arrangements described
in (i) to (iv) above.
Except where paragraph (d ) of this Code applies, each protective
conductor mentioned in (i) to (iv) above should comply with the
requirements of Codes 11B, 11C and paragraph (e) of this Code.
(g) Where items of stationary equipment having an earth leakage current
exceeding 3.5 mA in normal service are to be supplied from an
installation forming part of a TT system, it should be verified that the
product of the total earth leakage current (in amperes) and the resistance
of the installation earth electrodes (in ohms) does not exceed 25 volts.
Where compliance with this requirement cannot be otherwise achieved,
the items of equipment should be supplied through a double-wound
transformer or equivalent device as described in paragraph ( f )(vi) of this
Code.
26P Renewable Energy Power System
(1) Scope
The particular requirements of this Code should apply to renewable
energy power system (REPS) installations.
(2) Selection and erection of installation
The REPS installation should be selected and erected to ensure safe
operation and ease of maintenance at all times. The REPS should be
designed and installed in accordance with the requirements specified in
the Technical Guidelines on Grid Connection of Renewable Energy Power
Systems published by the Energy Efficiency Office (EEO) of EMSD as
appropriate and other relevant national / international standards such as
IEC 60364-7-712, IEC 61400-2, BS 7671 or equivalent.
(3) Inspection, testing and maintenance
An owner of the REPS should ensure that the REPS and its associated
electrical equipment be regularly inspected and maintained in a safe and
proper working condition in accordance with manufacturer’s guidelines /
instructions and the relevant requirements in the CoP. For REPS connected
in parallel with supply from an electricity supplier, special attention should
be paid to ensure that the REPS should be automatically disconnected
from the mains supply when the mains supply was tripped. During
maintenance, the power generation side of REPS should be isolated to
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