Section 411 contains a number of significant changes. Some of the main ones are mentioned below:
Metallic pipes entering the building having an insulating section at their point of entry need not be connected to the protective equipotential bonding (Regulation 411.3.1.2).
The maximum disconnection times stated in Table 41.1 now apply for final circuits up to 63 A with one or more socket-outlets and 32 A for final circuits supplying only fixed connected current-using equipment (Regulation 411.3.2.2).
Regulation 411.3.3 has been revised and now applies to socket-outlets with a rated current not exceeding 32A. There is an exception to omit RCD protection where, other than a dwelling, a documented risk assessment determines that RCD protection is not necessary.
A new Regulation 411.3.4 requires that, within domestic (household) premises, additional protection by an RCD with a rated residual operating current not exceeding 30 mA shall be provided for AC final circuits supplying luminaires.
Regulation 411.4.3 has been modified to include that no switching or isolating device shall be inserted in a PEN conductor.
Regulations 411.4.4 and 411.4.5 have been redrafted.
The regulations concerning IT systems (411.6) have been reorganized. Regulations 411.6.3.1 and 411.6.3.2 have been deleted and 411.6.4 redrafted and a new Regulation 411.6.5 inserted.
A new Regulation group (419) has been inserted where automatic disconnection according to Regulation 411.3.2 is not feasible, such as electronic equipment with limited short-circuit current.
18th Edition IET Wiring Regulations – Guidance Note Books
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