Bonding is the electrical connection of metallic components and equipment to ensure they maintain the same voltage and provide low-resistance paths for fault currents. Unlike grounding, which connects systems to earth, bonding connects all conductive objects to a common reference point. Bonding prevents dangerous voltage differences between surfaces and ensures fault currents flow safely through designed paths rather than through people or equipment.
Bonding Connections
Bonding conductors typically use copper wires sized from 8 to 2 gauge depending on service amperage. Connections must be mechanically secure using approved lugs and fasteners. Bonding jumpers bridge isolation points in piping and structural components. All connections require periodic inspection for corrosion and mechanical degradation that increases resistance.
HVAC System Bonding
HVAC equipment cases, metal framing, refrigerant piping, and electrical conduit must be bonded together and to the main ground reference. This prevents potential differences between components that could cause shock hazards or equipment damage. Bonding of refrigerant lines prevents static buildup that could ignite refrigerant during recovery operations.
Safety Benefits
Proper bonding reduces shock hazards and fire risk from arcing faults. Equipment operates more reliably when all components share common reference voltage. Bonding improves lightning protection and reduces electromagnetic interference affecting control circuits. Building codes mandate comprehensive bonding in all electrical installations.