Steel Trunking Quiz

Which of the following is a disadvantage of steel trunking?

• Minimises fire risks.

• Permits easy rewiring.

• Requires skill to fabricate and install.

• Can accommodate many cables of different sizes.

Answer explanation

The correct choice, 'Requires skill to fabricate and install,' highlights a disadvantage of steel trunking, as it necessitates specialized knowledge and expertise for proper installation, unlike other options that present advantages.

What does steel trunking permit that is beneficial for electrical systems?

• Easy rewiring.

• Increased cost.

• Corrosion.

• Difficult installation.

Answer explanation

Steel trunking allows for easy rewiring of electrical systems, making it convenient to modify or upgrade wiring without extensive labor or disruption. This flexibility is a key benefit for maintaining efficient electrical installations.

What is the thermosetting cable factor for a solid conductor with a cross-sectional area of 2.5 mm²?

• 8.6

• 11.9

• 13.9

• 16.6

Answer explanation

The thermosetting cable factor for a solid conductor is determined based on its cross-sectional area. For a 2.5 mm² conductor, the correct factor is 11.9, which is derived from standard electrical engineering tables.

For a stranded conductor with a cross-sectional area of 4 mm², what is the PVC cable factor?

• 8.6

• 12.6

• 16.6

• 21.2

Answer explanation

The PVC cable factor for a stranded conductor is calculated based on its cross-sectional area. For 4 mm², the correct PVC cable factor is 12.6, which is a standard value used in electrical installations.

For a stranded conductor with a cross-sectional area of 25 mm², what is the PVC cable factor?

• 73.9

• 47.8

• 35.3

• 21.2

Answer explanation

The PVC cable factor for a stranded conductor with a cross-sectional area of 25 mm² is calculated based on standard values. The correct factor is 73.9, which is commonly used for this size of conductor.

Which trunking dimension has a factor of 1555?

• 75 x 38 mm

• 75 x 50 mm

• 100 x 25 mm

• 100 x 38 mm

Answer explanation

The trunking dimension 75 x 50 mm corresponds to a factor of 1555, making it the correct choice. The other options do not match this factor.

Which trunking dimension corresponds to a factor of 39428?

• 300 x 200 mm

• 300 x 225 mm

• 300 x 300 mm

• 225 x 225 mm

Answer explanation

The area of the trunking dimension 300 x 300 mm is 90000 mm², which is the only option that can correspond to a factor of 39428 when considering the dimensions. The other options do not yield a matching factor.

Which trunking dimension has a factor of 3082?

• 200 x 38 mm

• 200 x 50 mm

• 200 x 75 mm

• 225 x 38 mm

Answer explanation

The trunking dimension 200 x 38 mm has a factor of 3082, making it the correct choice. The other options do not match this factor.

What size of cable trunking is required according to Table E6?

• 50 x 25mm

• 60 x 30mm

• 75 x 25mm

• 80 x 40mm

Answer explanation

According to Table E6, the required size of cable trunking is 75 x 25mm, which is suitable for the specified application, ensuring adequate space for the cables while maintaining compliance with standards.

What is the multiplication factor used for calculating the cable factor of 10mm² cables?

• 16.6

• 21.2

• 35.3

• 10

Answer explanation

The multiplication factor for calculating the cable factor of 10mm² cables is 35.3. This value is used to determine the current-carrying capacity of the cable in various installation conditions.