Supplementary Equipotential Bonding is required in bath and shower rooms where the risk of an electric shock is high due to moisture and low body resistance.
Bonding comprises of conductors being attached with suitable clamps to water and gas service pipes where they enter the building and to ensure all metallic equipment in rooms of high shock risk (e.g. bathrooms) is at the same potential.
Bonding Main/Supplementary Main and Supplementary Equipotential Bonding is required to limit any voltage between simultaneously accessible exposed conductive and extraneous conductive parts.
An exposed conductive part:
Metal case of electric heater, kettle, toaster, etc.
An extraneous conductive part:
Taps, shower fittings and metal pipes for gas and water.