Reducing differences in potential
Equipotential bonding connects conductive parts to reduce differences in potential between them. For electric shock prevention, it is particularly relevant when a person can touch two parts simultaneously. It differs from earthing: bonding seeks to equalise the potential of parts, while connection to the ground serves another function within the system.
Related concept: Electrical risk.
Which parts are connected
The design identifies exposed conductive parts of equipment and conductive elements capable of introducing a potential. Main and supplementary connections may be required for particular locations or situations. This does not mean indiscriminately connecting all metal: some protective systems have specific requirements, including separation from earth. The solution must respect the intended electrical arrangement.
Continuity cannot be assumed
Paint, insulating joints, corrosion, hinges or replaced sections may interrupt a connection that appears metallic. Connections must be suitable, verifiable and protected against damage. A pipe that needs bonding must not be confused with an improvised protective conductor for supplying equipment.
Relationship with static electricity
In transfers or processes involving electrostatic charging, connections between containers and equipment can help prevent potential differences capable of causing discharges. This purpose requires a specific analysis of the process and its materials. An electrical protective connection does not automatically prove that the whole operation controls static electricity.
Hypothetical example
After an installation is painted, a clamp is replaced over a coated surface. It appears mechanically secure, but electrical contact may have changed. Verification must confirm continuity of the intended connection. A record stating only “clamp present” does not demonstrate the required safety function.
Design, verification and limits
Document the points to be connected, their characteristics and the corresponding checks. A connection must not be removed for installation convenience without assessing the effect. Bonding complements applicable protective measures and does not permit contact with live conductors or work without isolation. Specific requirements depend on the location and electrical arrangement; the cited sources explain Spain’s low-voltage framework.
