General-Use Switch - see definition for Switch.
Gradient, Voltage - The voltage drop, or electrical
difference, between two given points.
Ground - A connection to earth obtained by a
Ground Counterpoise - a conductor installed over
(airport) lighting cables for the purpose of interconnecting
the system ground electrodes and providing lightning protection
Ground Fault - Any undesired current path from
a point of differing potential to ground.
Ground Fault Circuit Interrupter - A device whose
function is to interrupt, within a predetermined time, the electrical
circuit to the load when a current to ground exceeds some predetermined
value that is less than that required to operate the overcurrent
protective device of the supply circuit.
Class A Ground Fault Circuit Interrupter (GFCI) -
is a protective device that will interrupt the circuit to the
load when the ground fault current is 6 mA or more but not when
ground fault current is 4 mA or less (there will be a less then
10% current limit variation when the ambient air temperature
is less than –5 °C or more than 40 °C) in a time
- (a) not greater than that given by the equation T =
(20 / I)1.63, where
T is in seconds; and
I is the ground fault current
in rms milliamperes for fault currents between
4 mA and 260
- (b) not greater than 25 ms for ground fault currents over
In addition, a Class A GFCI is to be capable of interrupting the
circuit to the load, in keeping with the above requirements if the
identified circuit conductor (neutral) becomes inadvertently grounded
between the interrupter and the load. The prime function of a Class
A GFCI is to provide protection against hazardous electric shocks
from leakage current flowing to ground from defective circuits or
equipment. It does not provide protection against shock if a person
makes contact with two of the circuit conductors on the load side
of the GFCI.
Class A GFCIs are marked “GROUND FAULT CIRCUIT INTERRUPTER CLASS A” or
with an abbreviated form such as “GFCI CL A”, “GFCI A”,
or “CL A” where the area available for marking makes the complete
Grounding - A permanent and continuous conductive
path to the earth with sufficient ampacity to carry any fault current
liable to be imposed on it, and of a sufficiently low impedance
to limit the voltage rise above ground and to facilitate the operation
of the protective devices in the circuit.
Grounding Conductor - The conductor used to connect
the service equipment or system to the grounding electrode.
Grounding Electrode - A buried metal water-piping
system, or metal object or device buried in, or driven into, the
ground so as to make intimate contact therewith, to which a grounding
conductor is electrically and mechanically connected.
Grounded - Connected effectually with the general
mass of the earth through a grounding path of sufficiently low
impedance and having an ampacity sufficient at all times, under
the most severe conditions which are liable to arise in practice,
to prevent any current in the grounding conductor from causing
a harmful voltage to exist:
- Between the grounding conductors and neighbouring exposed conducting
surfaces which are in good contact with the earth; or
- Between the grounding conductors and neighbouring surfaces
of the earth itself.
Grounding System - All conductors, clamps, ground
clips, ground plates or pipes, and ground electrodes by means of
which the electrical installation is grounded.
Guarded - Means covered, shielded, fenced, enclosed,
or otherwise protected by means of suitable covers or casings,
barriers, rails or screens, or mats or platforms to remove the
liability of dangerous contact or approach by persons or objects.