Accessible as Applied to Wiring Methods - Means:
- Not permanently closed in by the structure or finish of the
- Capable of being removed without disturbing the building structure
Accessible as Applied to Equipment - Means admitting close approach
because the equipment is not guarded by locked doors, elevation,
or other effective means.
AL - Aluminum
Alive or Live - Means electrically connected to
a source of voltage difference, or electrically charged so as to
have a voltage different from that of the earth; and the term may
be used in place of the term "current-carrying".
Cable - A cable consisting of one or more conductors
of approved type assembled into a core and covered with a liquid-
and gas-tight sheath of aluminum or aluminum alloy.
Alternating Current (AC) - A flow of electricity which reaches
maximum in one direction, decreases to zero, then reverses itself
and reaches maximum in the opposite direction. The cycle is repeated
continuously. The number of cycles per second is equal to the frequency.
Amalgam - A mixture of different elements.
Amalgamate - The forming of an amalgam; the union of two materials;
Ambient Temperature - The temperature of the atmosphere of surrounding
environment. Typically defined by industry standards as 25° C.
Ampacity - The current-carrying capacity of electric conductors
expressed in amperes.
Ampere (A) - Unit of electrical current flow, or rate of flow
ANSI - American National Standards
Institute; Electrical standard developed and published as a result
of recommended practices and studies made by NEMA and IEEE.
Arc - Sparking that results when undesired current
flows between two points of differing potential.
Arc Voltage - The reaction of a circuit's inductance to the rate
of current change in the circuit; E = L(di/dt); when a current-limiting
fuse operates, there is an associated arc voltage on the system.
Arrester - A protective device for limiting surge voltages on
equipment by diverting surge current and returning the device to
its original status. It is capable of repeating these functions
Arrester Voltage Rating - RMS value of the maximum 60 Hz voltage
to which an arrester should be subjected, even under transient
Arrestor - See Arrester
Asymmetric - A term used to explain the offset current waveform
that can occur when a fault is initiated; the composite quantity
of the transient current (dc component) and the steady state current
(ac component); usually considered to be 1.6 times the symmetric
for most electrical distribution systems.
Authorized Person - A qualified person who by the nature of their
duties or occupation is obliged to approach or handle electrical
equipment, or a person who, having been warned of the hazards involved,
has been instructed or authorized to do so by someone having authority
to give the instruction or authorization.
Auxiliary Gutter - A raceway consisting of a sheet metal enclosure
used to supplement the wiring space of electrical equipment and
to enclose interconnecting conductors.
AWG - The American (or Brown and Sharpe) Wire Gauge as applied
to nonferrous conductors and nonferrous sheet metal.