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Electrical Installations Glossary
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Electrical Installations Glossary
Electrical Installations Glossary
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1
Question
What is a bonding ring conductor (BRC)?
Page 1
Answer
A bus earthing conductor in the form of a closed ring. Normally part of the bonding network with multiple connections to the common bonding network (CBN) that improves its performance.
2
Question
Define a booth in electrical installations.
Page 1
Answer
Non-stationary unit intended to accommodate equipment generally for pleasure or demonstration purposes. Building voids include space within partitions, suspended floors, ceilings, and certain types of window frames.
3
Question
Define building void, non-accessible.
Page 1
Answer
A space within the structure or components of a building which has no ready means of access.
4
Question
What does 'bunched' mean for cables?
Page 1
Answer
Cables are bunched when two or more are contained within a single conduit, duct, ducting, or trunking, or if not enclosed, not separated by a specified distance.
5
Question
What is a busbar trunking system?
Page 1
Answer
Type-tested assembly in the form of an enclosed conductor system comprising solid conductors separated by insulating material. Includes busbar trunking units with/without tap-off facilities, phase-transposition units, etc.
6
Question
Define bypass bonding conductor [444].
Page 1
Answer
Bonding conductor connected in parallel with the screens of cables.
7
Question
What is a cable channel?
Page 1
Answer
Enclosure situated above or in the ground, ventilated or closed, with dimensions not permitting access of persons but allowing access to conduits/cables during/after installation.
8
Question
Define cable cleat.
Page 1
Answer
Component of a support system consisting of elements spaced at intervals along the cable/conduit length to mechanically retain it.
9
Question
What is a cable coupler?
Page 1
Answer
Means of enabling connection or disconnection at will of two flexible cables. Consists of a connector and a plug.
10
Question
Define cable ducting.
Page 1
Answer
Enclosure of metal or insulating material, other than conduit or cable trunking, intended for protection of cables drawn in after erection.
11
Question
What is a cable ladder?
Page 1
Answer
Cable support consisting of a series of transverse supporting elements rigidly fixed to main longitudinal supporting members.
12
Question
Define cable tray.
Page 1
Answer
Cable support consisting of a continuous base with raised edges and no covering. May or may not be perforated.
13
Question
What is cable trunking?
Page 1
Answer
Closed enclosure normally of rectangular cross-section, one side removable or hinged, used for protection of cables and accommodation of other electrical equipment.
14
Question
Define cable tunnel.
Page 1
Answer
Corridor containing supporting structures for cables/joints/other wiring elements, dimensions allowing persons to pass freely throughout length. For caravan/touring requirements.
15
Question
Define cartridge fuse link.
Page 1
Answer
Device comprising fuse element or two or more in parallel, enclosed in cartridge filled with arc-extinguishing medium, connected to terminations.
16
Question
What is a central power supply system?
Page 1
Answer
System supplying required emergency power to essential safety equipment. Low power version limited to 500W for 3h or 1500W for 1h, normally maintenance-free battery and charging unit.
17
Question
What is a circuit in electrical installations?
Page 2
Answer
Assembly of electrical equipment supplied from same origin and protected against overcurrent by same protective device(s). Breaks abnormal currents like short-circuit.
18
Question
Define circuit-breaker, instantaneous trip (ICB).
Page 2
Answer
Circuit-breaker fulfilling only short-circuit portion of overcurrent protection. Contacts arranged to make/break all poles simultaneously or in definite sequence.
19
Question
What is a circuit protective conductor (cpc)?
Page 2
Answer
Protective conductor connecting exposed-conductive-parts of equipment to main earthing terminal.
20
Question
How does Class I equipment achieve protection against electric shock?
Page 2
Answer
Protection does not rely on basic insulation only; includes connection of exposed-conductive-parts to protective conductor in fixed wiring (BS EN 61140).
21
Question
Define Class II equipment.
Page 2
Answer
Protection against electric shock by supplementary insulation; no reliance on protective conductor or fixed wiring precautions (BS EN 61140).
22
Question
What is Class III equipment?
Page 2
Answer
Protection against electric shock relies on SELV supply; no higher voltages generated (BS EN 61140).
23
Question
Define cold tail.
Page 2
Answer
Interface between fixed installation and heating unit. Maximum short-circuit current handled by two devices in series.
24
Question
What is combined short-circuit protection?
Page 2
Answer
Overcurrent co-ordination of two OCPDs in series in short-circuit conditions, resulting in higher capability than one alone.
25
Question
Define common equipotential bonding system (CBN) [444].
Page 2
Answer
Equipotential bonding system providing both protective and functional equipotential bonding.
26
Question
What is a consumer unit?
Page 2
Answer
Type-tested co-ordinated assembly for control/distribution of electrical energy in domestic premises, with double-pole isolation, fuses/CBs/RCDs.
27
Question
Define continuity of service.
Page 2
Answer
Extent to which operation of electrical system approaches intended state of freedom from supply interruption.
28
Question
What is the control and protective switching device (CPS device)?
Page 3
Answer
Switching device capable of operation other than by hand, providing functions of contactor and OCPD.
29
Question
Define conventional impulse withstand voltage.
Page 3
Answer
Peak value of impulse test voltage at which insulation shows no disruptive discharge after specified impulses.
30
Question
What is current-carrying capacity of a conductor?
Page 3
Answer
Maximum current carried under specified conditions without steady-state temperature exceeding specified value.