To Bond or Not to Bond: That Is the Question

Bonding of electrical equipment plays a crucial role in maintaining the same potential between conductive parts likely to be energized and conductive parts liable to introduce a "zero" potential into the premises. Voltage rises between such parts is unsafe, as they may induce harmful currents through the human body, the magnitude of which may vary depending on a number of factors. This paper seeks to clarify the bonding requirements in low-voltage electrical systems, by using the concepts of Exposed-Conductive-Parts and Extraneous-Conductive-Part, present in IEC standards, applied to a proposed electric shock model of the human being. With the purpose to reduce the consequences of electric contacts, the authors propose objective criteria to decide whether conductive "dead" objects and enclosures of electrical equipment must be bonded or not.