these are free standing assemblies of switches, fuses, and/or circuit breakers, which normally provide switching and feeder protection to a number of circuits connected to a main source

a rubber or plastic washer inserted in a hole in a metal part to prevent grounding of a wire passing through the hole

makes a close circuit in either one of the two positions

all circuit conductors between the service equipment, the source of a separately derived system, or other power supply source and the final branch-circuit overcurrent device. Flasho

where the electricity enters and is regulated

unit of capacitance defined by the production of one volt across the capacitor terminals when a charge of one coulomb is stored

science dealing with the physical phenomena arising from the existence and interaction of electric charges. It is a form of energy generated by friction, induction or chemical change, having magnetic, chemical and radiant effect

enclosed channel designed expressly for holding wires, cables, or busbars with additional functions

electric current

device intended for on-off control of circuits and electrical isolation of equipment; a piece of apparatus or device for making, breaking, or changing the connection in an electrical current in the circuit

good conductors

the direction from a given position in which the contact is made it also indicates the number of times a contact is made.

insulating materials

effects of electric current

a conductor encased within material of composition and thickness that recognized by the code.

all switches except snap switches or knife switches mounted on a switchboard must be enclosed in an appropriate cabinet as a protection from external damage

conductor insulation

an insulating and protective lining for one or more conductors passing through a hole

a conductor having no covering or electrical insulation whatsoever

a protective device with a fusible element that opens the circuit by melting when subjected to excessive current.

electricity that flows through a substance or over its surface in the form of an electric current

father of electrcity

Greek philosopher of about this time, observed that amber, a stone-like substance attracted small bits of straw after being rubbed with cloth

the conductors that carry the current to all parts of the building

where the current is utilized

sources of electrcity

two types of mechanical electric

a branch of electrical science dealing with the laws of electricity at rest

one which will make a close circuit only when a circuit is thrown in one position

a conductor encased within material of composition or thickness that is not recognized by code as electrical insulation

form of electricity that appears to remain on the surface of a body as a change

a switch may be constructed with or without provision for fusing

that part of a switch, which is used for making or breaking a connection, and which is electrically insulated from other contact