Forums » Electrical Engineering

Grounding vs Bonding

    • 4 posts
    September 17, 2019 1:42 PM PDT

    Can somebody tell me the difference between grounding and bonding.


    • 29 posts
    September 17, 2019 3:39 PM PDT

    Grounding:  a continuous and permanent conductive path to the earth of sufficiently low impedance such that any available fault current imposed on it will result in a limited voltage rise

    Bonding: a low impedance path obtained by permanently joining all non-current carrying metal parts to ensure electrical continuity and having the capacity to safely conduct any current likely to be imposed upon it

    • 4 posts
    September 17, 2019 10:06 PM PDT

    Thank you.

    • 103 posts
    September 18, 2019 10:21 PM PDT

    In addition to to the NEC definitions provided by Derek

    Grounding or Earthing is for:

    Protection against Induced current caused by lightning.

    Protection against High voltage conductors being connected to low voltage system conductors. (Lines falling across them).

    Provides an earth reference for measurement.

    Has little effect in clearing a ground fault.


    Bonding Provides:

    Equal potential between all metal or conductive parts or enclosures. Under normal conditions this is ideally earth potential or zero volts.

    The low impedance return path for ground fault current to return to the source.  This will OPEN the OCPD to clear the ground fault. To accomplish this the path must be (1) electrically continuous (2) have the capacity to safely conduct any fault current likely to be imposed on it & (3) have sufficiently low impedance to limit the voltage to ground & facilitate to operation of the circuit protective devices.