Grounding is an electrical circuit. The grounding circuit can
be conductors or in some cases a conduit system is the grounding
circuit. The mechanical
connections of fittings, conduits, boxes, etc. are just as important as
connection of the circuit wires. Each mechanical fitting is a part of
the grounding circuit path and must be connected with just as much care
as the electrical circuit conductors. Very few faults occur between
wires in a conduit. The point of connection or termination is where
most faults take place.
It is not possible to use electricity
without involving some risk. It is impossible to prevent dangerous
voltages to ground on an electrical system unless we do away with
electricity completely because we cannot prevent a fault condition from
occurring. The job of the electrician is to hold that risk to a minimum
by installing protection which will reduce the existence of voltages to
ground on equipment to a minimum and hold the fault condition to a
minimum time duration.
We must understand what a circuit is. An
electrical circuit is a path or route of least resistance in which
electrons flow from the source of supply to accomplish the electrical
work and flow through the circuit back to the source of supply.
Sometimes too much emphasis is put on
one's knowledge of Code rules and sizing of bonding jumpers, electrode
conductors, etc. Before one can discuss proper sizing of grounding
conductors, you must first understand the reasons for grounding a
system, theory, Ohm's law and what takes place when a fault condition
occurs in the system.