C

CAD - Abbreviation for computer aided design

Capacitance - The property of isolated conductors to store an electrical charge. Capacitance can create limitations in the transmission of signals through circuits.

Capacitor - An electrical component which stores electrical charges. It consists of at least two metallic plates (conductors) separated by an insulator (a non-conducting dielectric material which may be solid, liquid, or gaseous). The capacitance of a given device depends upon the size and shape of the conductors, the distance between them, and the characteristics of the insulator. When used in conjunction with other components, it can provide a high-frequency filtering capability.

Capacitive Coupling - If an isolated conductor (or other electrical charge, such as lightning) is near to a second conductor, but is separated from it by air or some other insulator, the system forms a capacitor. An electric field is produced across the system creating a capacitive electrical path between the conductors. Also see coupling.

Category C, B, and A - Classes described by the ANSI Standard C62.41, which defines the surge waveforms that would be representative at various locations within a building. Category C products are intended for use at the main service panel or distribution panels that require large surge current handling capability. Category B defines mid-building, branch panel situations. Category A defines the local service panel or specific equipment.

CCTV - Abbreviation for closed-circuit television

Circuit breaker - A resettable alternative to the fuse, which created an open circuit under overcurrent or fault current conditions.

Clamping level - Describes to the voltage level that causes the surge suppression device to start to divert surge energy. A related, but more important parameter is the suppressed voltage.

Clean - Cable which is, supposedly, relatively free from interference

Closed-circuit television (CCTV) - A television system, other than broadcast television, which forms a closed circuit between television camera and receiver. CCTV has many commercial applications, eg. security systems.

Coaxial cable - A type of cable consisting of two concentric conductors separated by insulation, used to transmit high frequency (e.g.. television) signals.

Combination pulse - A high energy test pulse specified by ANSI C62.41-1999. Also called a "unipolar pulse".

Combination wave generator or hybrid generator - Transient test equipment designed to product voltage and/or current impulses of defined waveform.

Common mode - The voltage that appears between each of two or more conductors and earth. Also referred to as L-G and N-G.

Conductor - Material which electric current will easily pass through. Also, the set of wires, or conductors, which together from a power or data communication cable or supply. Power supplies typically consist of live/phase, neutral, and earth conductors. There is considerable variation in the names applied to the constituent conductors of data communication, signal, or telephone cable. Often there is one or more signal or line conductor(s) together with a screen and/or earth return conductor.

Conduit - A channel or pipe for mechanically protecting cables

Coupling - The interaction between two circuits which causes energy to be transferred from one to the other. This can be the result of capacitive, inductive, or resistive mechanisms

CP 326 - Code of practice (CP) superseded by BS 6651

Cross bond - To bond together two or more conductors

Cross coupling - see coupling

Current - The rate of flow of electrons through a conductor. Measured in amperes, or amp