Cabling

Question 1

What is the most common type of cabling used when wiring?

Answer 1

PVC cabling

Question 2

What does PVC stand for?

Answer 2

Poly Vinyl Chloride

Question 3

What are the two main forms of PVC cabling?

Answer 3

Thermoplastic and thermosetting

Question 4

What are 2 disadvantages of PVC cabling

Answer 4

Susceptible to damage when exposed to high temperature
Susceptible to brittleness when exposed to low temperature
Can produce harmful fumes that are toxic

Question 5

What is the maximum continuous operating temperature of thermoplastic PVC cabling?

Answer 5

70°C and the insulation will soften above this temperature

Question 6

What does XLPE stand for?

Answer 6

Cross-linked polyethelen

Question 7

What is the maximum continuous operating temperature of thermosetting PVC cable? and where are you likely to see this cabling?

Answer 7

90°C. In Mains cabling as it can work at higher temperatures

Question 8

What is LSF cable?

Answer 8

Low smoke and fume cable

Question 9

What is 6491X cable, what sizes are available, where can it be installed and what type of additional protection is needed when installed?

Answer 9

(6491X) cable is PVC insulated cable which comes in single conductors (No outer sheath)
Comes in sizes 1.0mm2 and upwards
Found in commercial, industrial and agricultural installs
requires extra mechanical protection, usually installed in conduit or trunking.

Question 10

What is 6242Y cable? what sizes are available? What extra protection is required? and how many conductors does it have?

Answer 10

6242Y is flat profile PVC insulated PVC sheathed flat twin and CPC cable generally used in domestic installs

Comes in sizes 1.5 mm2 and upwards
2.5 mm2 and 1.5 mm2 have solid conductors, Larger are stranded

Sheathing provides some mechanical protection and can be clipped directly without protection
Has 2 PVC insulated conductors and 1 un-insulated CPC

Question 11

What is 3092Y cable and 3093Y cable and where is it used? what sizes are available? And what is required of the conductor ends?

Answer 11

Is PVC insulated PVC sheated, 3092 is 2 core 3093 is 3 core
Sizes 0.5mm2 upwards
Used for portable appliances to socket and lighting points
Conductor ends must be suitable treated

Question 12

What is SWA cable? and where is it commonly used?

Answer 12

SWA is Steel Wired Armour cable consisting of single or multi core PVC copper or aluminum conductors
Used in main and sub-main cables
Can be buried directly in the ground so can be useful for connecting between buildings

Question 13

What are the typical sizes of SWA cables?

Answer 13

50-1000 m2 single core

1.5mm2 to 400m2 for 2,3 and 4 core types

Question 14

What can the wired armour in an SWA cable be used for?

Answer 14

The wire can be used for the CPC

Question 15

What are the main types of fire resistant cables?

Answer 15

FP200
(MICC) Mineral insulated copper clad
(MIMS) Mineral insulated metal sheathed

Question 16

What is MIMS cable insulated by?

Answer 16

Magnesium oxide powder

Question 17

What are the 3 main colours for fire resistant cable and where are they used?

Answer 17

White - Emergency Lighting
Red - used for fire alarms
Orange - General purpose

Question 18

List some advantages for MICC

Answer 18

Fire proof
Great Mechanical strength
Waterproof
Non-ageing
High current carrying capacity
Earth continuity
High corrosion resistance
High operating temperature

Question 19

Disadvantages for MICC cable

Answer 19

Moisture absorption
Complicated termination process
Cost

Question 20

What is CWZ compliance

Answer 20

C - Resistance to fire at 950°C
W - Resistance to fire and water at 650°C for 30 mins
Z - Resistance to fire and mechanical shock at 950°C for 15 mins

Question 21

List some advantages for FP200 cable?

Answer 21

Fire resistant
Good mechanical strength
Waterproof
Easy to terminate
Relatively cheap compared to MICC

Question 22

List Disadvantages of FP200 Cable

Answer 22

Types of silicone insulation require ferules to be fitted because insulation is brittle