What is the purpose of a bonding conductor in installations with metal pipes radiators and exposed metalwork?

• A. To increase insulating resistance.
• B. To transfer power to metalwork.
• C. To route cooling air.
• D. To equalize potential and reduce shock risk by connecting exposed metalwork to earth.

Answer: (C)

Bonding conductors are used to equalize electrical potential across all exposed metal parts in a installation, such as metal pipes and radiators. By tying these metal pieces to earth, any fault that energizes one part will raise the others to the same potential, greatly reducing the touch voltage a person could experience and lowering the risk of electric shock. It also provides a low-impedance path for fault current, helping protective devices trip quickly to isolate the fault. This function is different from increasing insulation resistance, transferring power to metalwork, or routing cooling air.