Supplementary Bonding in Bathrooms, –
The need for supplementary bonding has been reduced, as all new electrical installations in rooms containing a bath or shower need to have their circuits protected by a Residual Current Device (RCD), so you no longer have to carry out supplementary bonding in a bathroom if you have RCD/RCBO protection for all circuits that are in or pass through the bathroom.
In a room containing a bath or shower, additional protection must be provided for all circuits of the location using RCDs/RCBOs having the characteristics specified in Regulation 415.1.1which states:-
The use of RCDs with a rated residual operating current not exceeding 30 mA is recognized in AC systems as additional protection in the event of failure of the provision for basic protection and/or the provision for fault protection or carelessness by users.
(Regulation 701.411.3.3 refers: – Additional protection by RCDs
Additional protection by the use of one or more RCDs having the characteristics specified in Regulation 415.1.1 shall be provided for low voltage circuits: (i) serving the location (ii) passing through zones one and/or two not serving the location.
It is also required by BS 7671:2018+A2:2022 that the circuit(s) comply with the relevant requirements for automatic disconnection, such that the disconnection times will meet the requirements of Regulation Group 411.3.2, and that extraneous conductive parts are connected to the protective equipotential bonding according to
Regulation 411.3.1.2 Protective equipotential bonding which states: –
In each consumer’s installation within a building, extraneous conductive parts liable to introduce a dangerous potential difference shall be connected to the main earthing terminal by protective bonding conductors complying with Chapter 54. Examples of extraneous conductive parts may include:
(i) metallic water installation pipes
(ii) metallic gas installation pipes
(iii) other metallic installation pipework and ducting
(iv) central heating and air conditioning systems
(v) exposed metallic structural parts of the building.
Extracts from the BS7671:2018-A2:2022
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