UNIT 10: Wiring Systems Flashcards
1.
The minimum cross-sectional area for aluminium conductors of cables (except IS cables) used in hazardous areas should not be less than?
25mm
16mm
10mm
6mm
16mm
2.
The installation of equipment in hazardous locations essentially requires an understanding of which one of the following?
Combustion engine operation
Preparation of area classification diagrams
Protection types
Process instrumentation
Protection types
3.
Separation of the strands of cable cores may be prevented by?
Soldering or fitting core lugs
Twisting the strands
Fitting cable lugs or core-end sleeves
Soldering the strands
Fitting cable lugs or core-end sleeves
4.
A cable gland marked with a suffix ‘X’ may only be used with?
Portable equipment with additional clamping of the cable
Fixed equipment with additional clamping of the cable
An enclosure also marked with a suffix ‘X’
Fixed equipment.
Fixed equipment with additional clamping of the cable (within 300mm from the end of the gland)
Glands marked with an ‘X’ not to installed on transportable or portable equipment
5.
Which one of the following statements, given in BS EN60079-14, represents the knowledge and skills required by technicians for the selection and erection of equipment?
Quality assurance
Detailed knowledge of the relevant techniques
Familiarity with the relevant techniques
Detailed knowledge of the principles employed.
Familiarity with the relevant techniques
6.
Cables for non-intrinsically fixed equipment are required to be thermostatic, thermosetting or elastomeric provided they are?
Circular, compact, have extruded bedding and fillers;
Flat, compact, with extruded bedding and fillers;
Circular, compact, with extruded bedding & fillers are non-conductive
Circular, compact, have extruded bedding, and fillers, if any, are non-hygroscopic.
Circular, compact, have extruded bedding, and fillers, if any, are non-hygroscopic.
Ex d Barrier Glands
The connected cable is at least 3-meters in length
7.
The limitation for installation materials, such as cable tray, in an area requiring EPL Gc rated equipment is?
No limitations;
Contains no more than 7.5% aluminium:
Contains no more than 7.5% magnesium and titanium;
Contains no more than 7.5% magnesium, titanium and zirconium.
No limitations
8.
An enclosure is marked EEx d IIC, is direct entry and as a free internal volume of 1 litre and is installed in a group IIB area requiring EPL Gb (Cat 2G) equipment.
What is the minimum acceptable cable gland if round compact SWA cables with extruded bedding are used?
Certified E1WF, Ex d IIC barrier gland;
Certified E1W, Exe cable gland;
Uncertified E1W cable gland;
Certified E1WF, Ex d IIC cable gland
Certified E1WF, Ex d IIC cable gland
Because the Enclosure is installed within a Gas Group IIB Area the Gland only requires to a certified to E1WF Ex d IIC cable gland and a barrier gland does not need to be installed.
Gland Markings
A. Outer Seal only
A2. Unarmoured cable with outer seal.
B. Armour lock only.
BW. SWA cable without seal, indoor use.
BARR. Inner barrier seal, outer seal, and armour lock.
C. Outer Seal with armour lock.
CR-C Double compression, barrier gland, SWA, braided cable (Croclock)
CW. Single seal, SWA, outdoor use.
CX. Single seal, braided cable.
D. Inner seal and armour lock.
E. Double seal.
E1W. Double seal, SWA cable, indoor / outdoor.
E1X. Double seal, braided cable indoor / outdoor.
F. Multiple certification.
IE. Integral earth.
L. Lightweight design.
R. Reduced bore size.
T. Pliable wire armour, flexible cables.
W. Steel wire armour (SWA).
X. Wire braid
Y. Aluminium strip wire.
Z. Double steel tape armoured.
E1WF.
Double Seal, SWA, multiple certification
E1W
Double Seal, SWA
E1We
Double Seal, SWA, inner cable seal and outer cable seal.
BARR-W
Barrier gland, SWA or Tape bedding.
9.
Unused cable cores of multi-cored cables are required to be terminated by which one of the following?
Terminate in unearthed terminals
Cut back and insulate both ends with tape
Connect one end to the neutral conductor
Connect both ends to earth.
Terminate in unearthed terminals
10.
Which one of the following statements represents the assessment requirements for technicians as given in BS EN60079-14
A degree in electrical engineering
Evidence only of having the necessary skills for the scope of work
Evidence only of having the necessary skills for the scope of work and
competence across the range activities
Evidence indicating the necessary skills for the scope of work, competence across the range of activities and relevant knowledge and understanding
Evidence indicating the necessary skills for the scope of work, competence across the range of activities and relevant knowledge and understanding
11.
Which one of the following values, as given in BS EN60079-14, is the limit for the insulation resistance of plastic cable tray in order to avoid static electricity
Greater than 1 M ohms
Greater than 1 G ohms
Not exceeding 1 G ohms
Not exceeding 1 M ohms
Not exceeding 1 G ohms
12.
Before work is carried out in an hazardous location which one of the following is necessary to understand?
The manufacturer’s documentation
The basic requirements for working in the zones of hazardous areas
Circuit diagrams for panel wiring;
How the equipment operates;
The basic requirements for working in the zones of hazardous areas
13.
The reduction of static electricity on new plastic cable tray may be reduced by which one of the following
Limiting the cable tray surface area
Using braided armour cables
Limiting the cable tray length
Installing IS circuits only on the cable tray.
Limiting the cable tray surface area
14.
A compound filled barrier gland is required for which one of the following types of explosion protection?
An Ex n restricted breathing light fitting
A flameproof Ex d IIC T6 Junction Box
An intrinsically safe Ex ia pressure switch
A flameproof Ex d IIC T6 switch
A flameproof Ex d IIC T6 switch
15.
The competencies required of different groups of personnel are specified in BS EN60079-14. Which one of the following applies to technicians?
practical skills necessary for the preparation and compilation of relevant
design details for the concepts of protection and systems involved
Have the expertise to perform quality assurance audits
Production of Designers certificates to the user
Practical skills necessary for the preparation and installation of relevant
concepts of protection
Practical skills necessary for the preparation and installation of relevant
concepts of protection.
