Separately Derived System
A premises wiring system whose power is derived from a
battery, a solar photovoltaic system, or from a generator, transformer, or
converter windings, and that has no direct electrical connection, including
solidly connected grounded circuit conductor, to supply conductors
originating in another system.
Service Drop
Run of cables from
the power company's aerial power lines to the point of connection to a
customer's premises.
Service Conductors
The supply
conductors that extend from the street main or transformers to the service
equipment of the premises being supplied
Service Entrance Conductors
Overhead: The service conductors between the terminals of the service
equipment and a point usually outside the building, clear of building walls,
where joined by tap or splice to the service drop.
Underground: The service conductors between the terminals of the service
equipment and the point of connection to the service lateral.
Service Equipment
The necessary
equipment, usually consisting of a circuit breaker or switch and fuses and
their accessories, located near the point entrance of supply conductors to a
building and intended to constitute the main control and cutoff means for
the supply to the building.
Service Lateral
The underground
service conductors between the street main, including any risers at a pole
or other structure or from transformers, and the first point of connection
to the service-entrance conductors in a terminal box, meter, or other
enclosure with adequate space, inside or outside the building wall. Where
there is no terminal box, meter, or other enclosure with adequate space, the
point of connection is the entrance point of the service conductors into the
building.
Service Point
The point of
connection between the facilities of the serving utility and the premises
wiring.
Solenoid
An electromagnetic coil that contains a
movable plunger.
Surge
A short duration high
voltage condition. A surge lasts for several cycles where a transient lasts
less than one half cycle. Often confused with "transient".
Switchboard
A large single
panel, frame, or assembly of panels having switches, overcurrent, and other
protective devices, buses, and usually instruments mounted on the face or
back or both. Switchboards are generally accessible from the rear and from
the front and are not intended to be installed in cabinets.
Switch, general use
A switch
intended for use in general distribution and branch circuits. It is rated in
amperes and is capable of interrupting its rated voltage.
Switch, general-use snap
A type
of general-use switch so constructed that it can be installed in flush
device boxes or on outlet covers, or otherwise used in conjunction with
wiring systems recognized by the National Electric Code.
Switch, isolating
A switch
intended for isolating an electrical 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.
Switch, knife
A switch in which
the circuit is closed by a moving blade engaging contact clips.
Switch, motor-circuit
A switch,
rated in horsepower, capable of interrupting the maximum operating overload
current of a motor of the same horsepower rating as the switch at the rated
voltage.
Switch, transfer
A transfer switch is an automatic or non-automatic
device for transferring one or more load conductor connections from one
power source to another.
Switch-Leg
That part of a
circuit run from a lighting outlet box where a luminaire or lamp-holder is
installed down to an outlet box that contains the wall switch that turns the
light or other load on or off: it is a control leg of the branch circuit.
