Electrical Switch Definitions
- AIR SWITCH
- An air switch is a switch in which the interruption of the
circuit occurs in air. Air is used as the insulation
medium between the open contacts (air break switch).
- CENTER BREAK SWITCH
- A center break switch is a switch with two rotating
insulators, located at each end of the base. Rotation of
the insulators cause the blade and contact to engage at a
point approximately midway between the insulators.
- DISCONNECTING SWITCH
- A disconnecting switch is an air switch used for changing
connections in a circuit or system, or for isolating
purposes. It is intended to be operated only after the
circuit has been opened by some other means. It has no
- DOUBLE BREAK SWITCH
- A double break switch is a switch which opens the
connected circuit at two points.
- DOUBLE THROW SWITCH
- A double throw switch is a switch by means of which a
change in circuit connections can be obtained by closing
the switch blade into either of two sets of contacts.
- FULL LOAD INTERRUPTERS SWITCH
- Is an interrupter switch having a current interrupting
rating, under specific circuit conditions, equal to the
continuous current rating of the switch at rated voltage.
- FUSED DISCONNECTING SWITCH
- A fused disconnecting switch is a disconnecting switch in
which a fuse unit forms a part of the blade.
- GROUNDING SWITCH (Ground Switch)
- A grounding switch is a form of an air switch by means of
which a circuit or a piece of apparatus may be connected
- HIGH SPEED GROUNDING SWITCH
- Is a grounding switch which incorporates a stored energy
mechanism capable of providing a high contact closing
speed, at its rated current, independent of the operator.
The switch is either opened manually or by a power
- HORN GAP SWITCH
- A horn gap is a form of an air switch which is provided
with arcing horns.
- INTERRUPTER SWITCH
- An interrupter switch is a combination of an air
disconnect switch and a circuit interrupter, which has a
current interrupting rating, under specific circuit
conditions, equal to or less than the continuous rating of
the switch at rated voltage.
- ISOLATING SWITCH
- An isolating switch is a switch intended for isolating an
electric circuit from the source of power. It has no
interrupting rating and is intended to be operated only
after the circuit has been opened by some other means.
- LIMITED CURRENT INTERRUPTER SWITCH
- Is an interrupter switch limited to certain types of
application, where the types and magnitude of certain
interruptions, at rated voltage, is less than the
continuous current rating of the switch such as small load
currents, magnetizing currents, or capacitor currents.
- MOUNTING POSITION OF AN AIR SWITCH
- The mounting position of an air switch is determined by
and corresponds to the position of the base of the switch.
The usual positions are:
- Horizontal upright
- Horizontal underhung
- OIL SWITCH
- An oil switch is a switch in which the interruption of the
circuit occurs in oil. Oil is used as the insulation
medium between the open contacts.
- ROTATING INSULATOR SWITCH
- A rotating insulator switch is a switch in which the
opening and closing travel of the blade is accomplished by
the rotation of one or more of the insulators supporting
the conducting parts of the switch.
- SECTIONALIZING SWITCH
- A sectionalizing switch is a switch used for connecting or
disconnecting adjacent sections of conductors or feeders.
- SELECTOR SWITCH
- A selector switch is a form of air switch arranged so that
a conductor may be connected to any one of several other
- SIDE BREAK SWITCH
- A side break switch is a switch in which the travel of the
blade is in a plane parallel to the base of the switch.
- SINGLE BREAK SWITCH
- A single break switch is a switch which opens the
connected circuit at one point only.
- SINGLE THROW SWITCH
- A single throw switch is a switch by means of which the
circuit can be opened or closed by moving the switch blade
into or out of one set of contacts only.
- A switch is a device for making, breaking, or changing the
connections in an electric circuit.
- TILTING INSULATOR SWITCH
- A tilting insulator switch is a switch in which the
opening and closing travel of the blade is accomplished by
a tilting movement of one or more of the insulators
supporting the conducting part of the switch.
- VERTICAL BREAK SWITCH
- A vertical break switch is a switch in which the travel of
the blade is in a plane perpendicular to the plane of the
- DIRECT OPERATION
- Direct operation of a mechanically operated switch is the
operation by means of a mechanism connected directly to
the main operating shaft, or an extension of it.
- GROUP OPERATION
- Group operation of a multipole switch is the operation of
all poles by means of one operating mechanism.
- HOOK OPERATION
- Hook operation of a switch is the operation manually by
means of a switch hook.
- INDIRECT OPERATION
- Indirect operation of a switch is the operation by means
of an operating mechanism connected to the main operating
shaft, or an extension of it, through offset linkage and
- MANUAL OPERATION
- Manual operation of a switch is the operation by hand
without using any other source of power.
- MECHANICAL OPERATION
- Mechanical operation of a switch is the operation by means
of an operating mechanism connected to the switch by
mechanical linkage. The operating mechanism may either be
hydraulic, pneumatic, or a combination of both. The
mechanical operation of a switch may be actuated either
manually, or electrically, or by other suitable means.
- OPERATING MECHANISM
- The operating mechanism of a switch is a power operated or
manual mechanism by which the contacts of all poles are
- The operation of an air switch is the method provided to
perform its normal function, that of opening or closing.
- POWER OPERATION
- Power operation of a switch is the operation by power,
such as motor operator, spring operator, pneumatic
operator, or hydraulic operator.
- REMOTE CONTROLLED OPERATION
- Remote controlled operation of a switch is the operation
by means of an operating mechanism controlled from a
distant point either manually and/or electrically or by
CONSTRUCTION & PARTS
- ARCING CONTACTS (ARCING HORNS) (PARKING HORNS)
- Arcing contacts are the contacts on which the arc is drawn
after the main contacts of a switch have parted.
- A base of a switch is the main member to which the
conducting parts or insulator unit are attached. It may
also have parts of the operating or control mechanism
- BELL CRANK or OUTBOARD BEARING
- A bell crank is a lever with two or more arms placed at an
angle diverging from a given pivot point, by means of
which the direction of motion of a mechanism is changed.
- BELL CRANK HANGER
- A bell crank hanger is a support for a bell crank.
- A switch blade is the moving contact member which moves to
engage or disengage the conductors.
- BLADE GUIDE
- A blade guide of a switch is an attachment to secure
proper alignment of blade and contact when closing the
- BLADE LATCH
- A blade latch is a latch used on a switch to hold the
switch blade in the closed position.
- A clevis is a fitting having a U-shaped end and arranged
for attaching to the end of a pipe or rod.
- The contact is a conducting part designed to be united by
pressure to another conducting part for the purpose of
- CONTACT SURFACES
- Contact surfaces are the surfaces of contacts which meet
and through which the current is transferred when the
contacts are closed.
- CURRENT CARRYING PARTS
- Current carrying part is a conducting part intended to be
connected in an electric circuit to a source of voltage.
- EXTENDED OUTRIGGER CLAMP
- An extended outrigger clamp is an attachment fastened to
the terminal pad of a switch to which the conductor is
clamped to relieve mechanical strain on the terminal.
- INTERPHASE CONNECTING RODS
- Interphase connecting rods are the rods connecting the
several poles of a switch together, and to the operating
- LIVE PARTS
- Live parts are those parts which are electrically
connected to points of potential different from that of
- MOVING CONTACT MEMBER
- A moving contact member of a switch is a conducting part
which bears a contact surface that moves to and from the
- OPERATING RODS
- Operating rods or pipes connecting the interphase
connecting rods or pipes and the operating mechanism of an
- An outrigger is an attachment which is fastened to or
adjacent to the terminal pad of a switch and to which the
conductor is clamped to relieve mechanical strain on the
terminal and/or to maintain electrical clearance between
the conductor and the grounded parts.
- PIPE END (ROD END)
- A pipe end is a fitting arranged to connect the end of a
pipe or rod to a lever, bell crank, or other part.
- A pole of a switch consists of the parts necessary to
control one conductor of a circuit. A switch may be single
pole or multipole, depending upon the number of single
poles that are operated simultaneously.
- SLEET HOOD
- A sleet hood of a switch is a cover for the contacts to
prevent the accumulation of sleet from interfering with
the successful operations of the switch.
- STATIONARY CONTACT MEMBER
- A stationary contact member of a switch is a conducting
part which bears a contact surface that remains
- SWITCH MECHANISM
- A switch mechanism is an assembly of levers and other
parts which actuate the moving contacts of the switch.
- TERMINAL PAD
- A terminal pad of a switch is the extension provided on
the switch to which the terminal connection is fastened.
- WIRE GUIDE
- A wire guide is an attachment to maintain a conductor in a
definite position with relation to the switch.
- Clearance is the minimum distance between two conductors,
between conductors and supports or other objects, or
between conductors and ground.
- Corona is a luminous discharge due to ionization of the
air surrounding a conductor around which a voltage
gradient exists exceeding a certain critical value.
- Drip-proof means go constructed or protected that its
successful operation is not interfered with when subjected
to falling moisture or dirt.
- Drip-tight means so constructed or protected as to exclude
falling moisture or dirt.
- A ground is a conducting connection, between an electric
circuit or equipment and earth, or to some conducting body
which serves in place of' the earth.
- Grounded means connected to earth or to some conducting
body which serves in place of the earth.
- GROUNDED PARTS
- Grounded parts are those parts which are so connected
that, when the installation is complete, they are
substantially of the same potential as the earth.
- INSULATOR UNIT (INSULATOR STACK)
- The insulator unit of an air switch is the insulating part
or assemblies that isolates the current carrying parts
- An interlock is a device actuated by the operation of some
other device with which it is directly associated, to
govern succeeding operation of the same or allied devices.
- MINIMUM CLEARANCE BETWEEN POLES
- The minimum clearance between poles is the shortest
distance between any live parts of adjacent poles.
- MINIMUM CLEARANCE TO GROUND
- The minimum clearance to ground is the shortest distance
between any live part and adjacent grounded parts.
- PHASE SPACING
- The phase spacing of air switches is the distance between
centers of the live parts or conductors of one pole and
the current carrying parts of an adjacent pole.
- QUICK BREAK
- A switch is quick break when it has a high contact opening
speed independent of the operator.
- QUICK MAKE
- A switch is quick make when it has a high contact closing
speed independent of the operator.
- SPARK GAP
- A spark gap is an arrangement of two electrodes between
which a disruptive discharge or electricity may take
place, and such that the insulation is self restoring
after the passage of a discharge.
- SWITCH HOOK
- A switch hook is a hook provided with an insulating handle
for opening and closing hook operated switches.
- VOLTAGE TO GROUND
- The voltage to ground is the voltage between any live
conductor or a circuit and the earth.
- Watertight means provided with an enclosing case which
will exclude water applied in the form of a hose stream
for a specific time.
- WEATHERPROOF - (OUTDOOR)
- Weatherproof means so constructed or protected that
exposure to the weather will not interfere with its