274 Wiring Regulations in BriefWR-701.415.2 In locations containing a bath and/or a shower, local supplementary equipotential bonding shall be established connecting together the terminals of the protective conductor of each circuit supplying Class I and Class II equipment to the accessible extraneous conductive parts, within a room containing a bath or shower, including the following:���metallic pipes supplying services and metallic waste pipes (e.g. water, gas) metallic central heating pipes and air conditioning systems accessible metallic structural parts of the building (metallic door architraves, window frames and similar parts are not considered to be extraneous conductive parts unless they are connected to metallic structural parts of the building).Supplementary equipotential bonding may be installed outside or inside rooms containing a bath or shower, preferably close to the point of entry of extraneous conductive parts into such rooms. All extraneous conductive parts in zones 0, 1 and WR-702.411.3.3 2 of a swimming pool (and/or other basins) shall be connected by supplementary protective bonding conductors to the protective conductors of exposed conductive parts of equipment situated in these zones. A supplementary bonding conductor connecting two WR-544.2.1 exposed conductive parts shall have a conductance (if sheathed or otherwise provided with mechanical protection) not less than that of the smaller protective conductor connected to the exposed conductive parts.Note: If mechanical protection is not provided, its cross-sectional area shall be not less than 4 mm2. A supplementary bonding conductor connecting an WR-544.2.2 exposed conductive part to an extraneous conductive part shall have a conductance (if sheathed or otherwise provided with mechanical protection) not less than half that of the protective conductor connected to the exposed conductive part.
