Electrical Bonding and Grounding are Extremely Important
Not only is grounding
important for safety reasons. Electrical equipment frequently requires a
comparison to a conductor without voltage to operate correctly.
A bonded ground connection
ensures that all exposed conductive surfaces are at the same electrical
potential as the surface of the Earth to avoid the risk of electrical shock if a
person touches a device in which an insulation fault has occurred. Grounding
ensures that in the case of an insulation fault (a "short circuit"), a very high
current flows, which will trigger an over current protection device (fuse,
circuit breaker) that disconnects the power supply
From Wikipedia
- Electrical bonding is
the practice of intentionally electrically connecting all metallic non-current
carrying items in a room or building as protection from electric shock. If a
failure of electrical insulation occurs, all metal objects in the room will have
the same electrical potential, so that an occupant of the room cannot touch two
objects with significantly different potentials. Even if the connection to a
distant earth ground is lost, the occupant will be protected from dangerous
potential differences.
Bonding refers to the
fact that in a building with electricity it is normal for safety reasons to
connect all metal objects such as pipes together to the mains earth to form an
equi-potential zone. This is done in the UK because many buildings are supplied
with a single phase supply cable where the neutral and earth conductors are
combined. Close to the electricity meter this conductor is divided into two, the
earth terminal and the wire going to the neutral busbar in the consumer unit. In
the event of a break in a neutral connection this earth terminal provided by the
supply company will be at a potential (relative to the true earth) which is the
same as the live wire (phase wire) coming to the home.
Examples of articles that
may be bonded include metallic water piping systems, gas piping, airplanes,
ducts for central heating and air conditioning systems, and exposed metal parts
of buildings such as hand rails, stairs, ladders, platforms and floors.
Also from Wikipidia -
How Ground Works
In a system with a grounded (earthed) neutral, connecting all
non-current-carrying metallic parts of equipment to earth ground at the main
service panel, will ensure that current due to faults (such as a "hot" wire
touching the frame or chassis of the device) will be diverted to earth.
Grounding will allow the branch circuit over current protection (a fuse or
circuit breaker) to detect the fault rapidly and interrupt the circuit
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