The primary purpose of bonding is to:

Grounding and bonding are related but not the same. • Grounding = connecting to earth (grounding electrode system) for stabilization of voltage and lightning/surge reference (not primarily for clearing faults). • Bonding = connecting metal parts together (and to the equipment grounding path) to create a low-impedance fault-current path so breakers/fuses trip quickly on a fault. Worked example (fault clearing): If a hot conductor contacts a metal enclosure, bonding ensures that enclosure is effectively connected to the EGC path back to the source, allowing high fault current so the breaker... Show more

Grounding and bonding are related but not the same.
• Grounding = connecting to earth (grounding electrode system) for stabilization of voltage and lightning/surge reference (not primarily for clearing faults).
• Bonding = connecting metal parts together (and to the equipment grounding path) to create a low-impedance fault-current path so breakers/fuses trip quickly on a fault.

Worked example (fault clearing):
If a hot conductor contacts a metal enclosure, bonding ensures that enclosure is effectively connected to the EGC path back to the source, allowing high fault current so the breaker trips quickly.

Worked example (ground rod myth):
A ground rod alone is NOT an effective fault clearing path (too much resistance). Bonding/EGC back to the source is what clears faults.
 

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