S.L. 545.24 ст. 20Protective devices to be provided at thesupplypointfor installations not exceeding60Amps per phase.

(1) Single phase electrical installations and three phase installations not exceeding 60 Amps per phase shall be provided with a main double pole switch fuse or circuit breaker or four pole switch fuse or four pole circuit breaker as applicable immediately after of the electricity service meter to control the supply input to the installation.

(2) Fuses and circuit breaker devices shall be graded to provide over current discrimination with the fuses provided by the electricity supply service.

(3) The main switch fuse or circuit breaker shall be mechanically linked so as to effect simultaneous disconnection of all live conductors phases and neutral.

(4) An overvoltage protective device to detect and protect against sustained overvoltage shall be installed immediately after the main switch fuse or circuit breaker: Provided that in the case of a multi-customer facility it shall be acceptable to install the over voltage protective device at the supply intake point in the customer’s premises:

Provided further that any circuits supplied upstream of the over voltage protection device shall also be protected by an over voltage protective device.

(5) One (1) or more residual current devices protecting individual sub-circuits separately of the appropriate type, taking into account the presence of any direct current leakage components and their magnitude with means for periodic inspection and with a tripping current of 30mA to earth shall be installed immediately after the over voltage protection device: Provided that in the case of a multi- customer facility it shall be acceptable to install a residual current device of the appropriate type, taking into account the presence of any direct current leakage components and their magnitude, with a tripping current of not more than 100mA, or a tripping current of 30mA with time discrimination, near the metering point, followed by a residual current protection device or more of the appropriate type taking into account the presence of any direct current leakage components and their magnitude, protecting individual subcircuits separately with a tripping current of 30mA, at the supply intake point in the customer’s premises or parallel circuits supplied from the same customer meter:

Provided further that where in the opinion of the authorised provider the unintended interruption of supply gives rise to greater risks, such as the de-energising of life support and emergency equipment, alternative arrangements for the sub-circuit supplying such equipment may be made by the authorised provider:

Provided further that in the case of circuit-specific loads with high earth leakage currents, such as in the case of circuits supplying electronic equipment, which may cause unintended interruptions of supply, a residual current protection device of the appropriate type, taking into account the presence of any direct current leakage components and their magnitude and if necessary with a tripping current higher than 30mA, as recommended by the manufacturer, which shall not however exceed 300mA, may be used at the supply intake after the overvoltage protection to protect that specific load only, with any other parallel and, or downstream sub-circuits, including common parts, in particular, those circuits supplying electrical loads accessible to users to be protected by one

(1) or more residual current devices with a tripping current of 30mA: Provided further that cables supplying specific loads protected by a residual current device, of the appropriate type, taking into account the presence of any direct current leakage components and their magnitude, with a tripping current exceeding 30mA shall be laid in protective conduit or trunking that provides appropriate mechanical protection. A metallic armoured cable may also be used as an alternative to the aforementioned arrangement:

Provided further that the authorised provider shall ensure that an appropriate warning sign is provided indicating that the equipment is protected with a residual current device with a tripping current higher than 30mA.

(6) In the case of electrical installations in multi-consumer facilities referred to in sub-regulation (5), the circuit between the main switch fuse or circuit breaker and the individual customer’s premises shall consist of main supply cables that run in a separate and individual protective conduit or in an individual trunking system dedicated for electricity supply wiring, to the individual customer’s premises. Separate and independent metallic armoured cable may also be used as an alternative to the aforementioned arrangement.

(7) Any compartment used in the electrical installation shall be of the non metallic and non-hygroscopic type.