Data communications, conduit and trunking types

Question 1

What is a LAN and what is it used for?

Answer 1

A LAN is a local area network, and is installed in an organisation to link computers, servers and printers together.

Question 2

What Frequency does CAT 3 support?

Answer 2

Cat 3 supports frequency’s upto 16 MHz

Question 3

What Frequency does CAT 4 support?

Answer 3

CAT 4 supports frequency’s upto 20 MHz

Question 4

What Frequency does CAT 5 Support?

Answer 4

CAT 5 supports frequency’s upto 100 MHz

Question 5

What Frequency does CAT 6 and CAT 6(a) support?

Answer 5

CAT 6 supports frequency’s upto 250 MHz and 6(a) supports frequency’s upto 500 MHz

Question 6

What is the maximum length a CAT 5 cable should be before being put into a a switch or repeater?

Answer 6

A CAT 5 cable should be no longer that 100m. This allows for 90m of cabling two connectors and two five metre patch leads

Question 7

What is the bend radius of CAT 5 cable

Answer 7

Bend radius should be 4 time the overall diameter of the cable.

Question 8

What is Fibre optic cable?

Answer 8

Fibre optic cable consists of one or more optical fibres, it then consists of a cladding and coating for total internal reflection.

Question 9

How is data projected on a fibre optic cable?

Answer 9

A light source is projected in one end and is reflected off the borders between the core and cladding. By switching light source on and off vast quantities of data is transmitted.

Question 10

What are some advantages of fibre optic transmission?

Answer 10

Very Large data transfer rate
No electromagnetic interference
Longer lengths of run without need for repeaters
Better data security

Question 11

What are some disadvantages of fibre optic transmission?

Answer 11

High installation cost
Complicated installation procedure
Possible health risk during installation

Question 12

What are 2 hazards associated with fibre optic cable?

Answer 12

When stripping it is possible a small shard of fibre could enter the blood stream and cause fatal damage
You should never look down a fibre cable as the laser could fire and damage your eyes

Question 13

Define an auxiliary circuit

Answer 13

is a circuit for transmission of signals intended for control, detection, supervision or measurement of the functional status of a main circuit.

Question 14

Give an example of an auxiliary circuit

Answer 14

DOL a direct online starter and a heating control circuit

Question 15

Give an example of different types of wiring environments

Answer 15

Domestic 
Commercial
Hazardous
Industrial 
Agricultural

Question 16

Give an example of cable which can be ‘Clipped Direct’

Answer 16

MICC - Mineral insulated
SWA - Steel wired armour
XLPE - Cross linked polyethelene
PVC/PVC - Polyvinyl chloride / Polyvinyl chloride

Question 17

What are some advantages of steel conduit and trunking?

Answer 17

They are strong and able to resist mechanical stress, they can also be used as CPC
Pemit easy wiring
minimise fire risk

Question 18

Where is plastic conduit and trunking most likely to be used?

Answer 18

Plastic conduit is most likely to be used in commercial premises with single core cables.

Question 19

What is an advantage and disadvantage of PVC conduit

Answer 19

it is less robust than steel conduit although easier to install.
lightweight 
Simple to form and bend 
Minimal condensation
Electrical and fire resistant

Question 20

Where would cable tray most likely be used?

Answer 20

Cable tray would be used in situations where individual clipping is difficult or not economical. Typically used above ceilings or industrial settings.

Question 21

What range of sizes does cable tray come in?

Answer 21

50mm to 1000mm

Question 22

Where is ladder rack used?

Answer 22

Ladder rack is used in industrial settings, where a large number of sub-main cables must be run

Question 23

Where is basket tray most likely to be used?

Answer 23

Basket tray is most likely to be used in commercial premises to run data cabling and small power cabling.

Question 24

What are the 3 main types of tray and conduit?

Answer 24

PVC
Metal
Flexible

Question 25

List some disadvantages of disadvantage of steel conduit

Answer 25

moisture is likely to form inside steel conduit
expensive to install
Liable to corrosion

Question 26

List 2x different types of finish for steel conduit

Answer 26

galvanized for outdoors

Black enameled for general work

Question 27

List Disadvantages of PVC conduit

Answer 27

Care must be taken when gluing joint to avoid forming a barrier inside of conduit
If insufficient adhesive is used joints may not be waterproof
PVC expands 5 times as much as steel

Question 28

List the 4 different type of PVC conduit

Answer 28

Heavy Gauge Super high impact
Light gauge super high impact
Heavy gauge standard impact
Heavy Gauge high temperature material

Question 29

What are the 3 main types of trunking

Answer 29

Metal
PVC
Mini trunking

Question 30

List some advantages of steel trunking

Answer 30

Affords conductors good mechanical protection
Can accommodate many cables of different sizes
Permits easy wiring
Minimise fire risks
Can be utilized as CPC

Question 31

List some disadvantages of steel trunking

Answer 31

Expensive compared with other systems
requires skill to fabricate and install
difficult to make gas and waterpoof
liable to corrosion

Question 32

What are the three main types of cable tray

Answer 32

Standard duty cable tray
Heavy duty cable tray
Return flange cable tray

Question 33

Where is cable ladder used and what is it used for?

Answer 33

Used in industrial settings

used for larger cables