A new bathroom installation rarely requires supplementary bonding.
In a room containing a bath or shower, additional protection must be provided for all circuits of the location by means of an RCD having the characteristics specified in Regulation 415.1.1 (Regulation 701.411.3.3 refers). It is also required by BS 7671 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.
In such circumstances supplementary bonding may be omitted, as indicated by Regulation 701.415.2.
Regulation 701.415.2 (part of)
Where the location containing a bath or shower is in building with a protective equipotential bonding system in accordance with Regulation 411.3.1.2, supplementary equipotential bonding may be omitted where all of the following conditions are met:
(i) All final circuits of the location comply with the requirements for automatic disconnection according to 411.3.2
(ii) All final circuits of the location have additional protection by means of an RCD in accordance with 701.411.3.3
(iii) All extraneous-conductive-parts of the location are effectively connected to the protective equipotential bonding according to 411.3.1.2.
