Part P Cable Selection and Wiring Systems 3

Question 1

What does the abbreviation 'MICC' stand for in cable terminology?

Accepted Answer

Mineral Insulated Copper Clad

Answer

Mineral Insulated Copper Covered

Answer

Metal Insulated Cable with Copper Core

Answer

Multi-Insulated Copper Conductor

Question 2

What is the maximum continuous conductor operating temperature for standard PVC insulated and sheathed cables (e.g., twin and earth)?

Accepted Answer

70°C

Answer

50°C

Answer

90°C

Answer

105°C

Question 3

In which situation would XLPE (cross-linked polyethylene) insulated cable be preferred over standard PVC cable?

Accepted Answer

When higher operating temperatures or better chemical resistance is required

Answer

When a lower cost option is required

Answer

When the cable must match existing cable colours

Answer

When the cable run is very short

Question 4

When steel conduit is used as a wiring enclosure in a domestic installation, how must it be connected to the earthing system?

Accepted Answer

It must be bonded to the main earthing terminal to ensure a fault return path

Answer

It does not need to be earthed as it only encloses cables

Answer

It should be insulated from earth to prevent stray currents

Answer

It is automatically earthed through the cable's insulation

Question 5

What is the primary function of PVC cable trunking in a domestic or light commercial electrical installation?

Accepted Answer

To provide a neat, organised, and protected route for multiple cables

Answer

To increase the current-carrying capacity of grouped cables

Answer

To reduce voltage drop over long cable runs

Answer

To act as the circuit protective conductor for all enclosed cables

Question 6

When new brown/blue cables (post-2004 colours) are joined to an existing installation using old red/black cables, what action must be taken?

Accepted Answer

A warning notice indicating mixed cable colour codes must be fixed at the consumer unit

Answer

Nothing — only the physical connections matter, not the colours

Answer

The complete circuit must be rewired with matching colours before energising

Answer

The old cables must be painted to match the new colour scheme

Question 7

What key advantage does Steel Wire Armoured (SWA) cable offer over standard twin and earth cable when supplying an outdoor detached garage or outbuilding?

Accepted Answer

Its steel wire armour provides mechanical protection, allowing direct burial or exposed runs without additional conduit

Answer

It can carry more current for the same conductor CSA

Answer

It is significantly cheaper to purchase and install

Answer

It requires no earthing arrangement at the outbuilding