What are the three main types of supply?

• TN-S

• TT

• TN-C-S

• TN-R

What are the advantages of conduit systems?

• Cannot be used as the circuit protective conductor

• Increases fire risks

• Affords conductors good mechanical protection

• Requires frequent rewiring

What are the typical sizes of steel conduit?

• 10mm, 15mm, 20mm, 25mm

• 18mm, 22mm, 28mm, 36mm

• 16mm, 20mm, 25mm, 32mm

• 30mm, 35mm, 40mm, 45mm

What is the disadvantage of PVC conduit systems?

• Minimal condensation due to low thermal conductivity in walls

• Does not require painting

• Light in weight and easy to handle

• Affected by temperature and oils

What is the typical size of PVC conduit for the given cables?

• 32mm

• 16mm

• 20mm

• 25mm

What is the total cable factors for the given cables in Example 1?

• 172

• 120

• 336

• 442

What is the size of conduit required for the given cables in Example 2?

• 20mm

• 25mm

• 30mm

• 35mm

What type of PVC conduit is suitable for pre-cast and in situ concrete work?

• Light Gauge Super High Impact

• Heavy Gauge Standard Impact

• Heavy Gauge High Temperature Material

• Heavy Gauge Super High Impact

What is the disadvantage of steel conduit systems?

• Does not require bending or clipping of cables

• Minimal condensation due to low thermal conductivity in walls

• Requires frequent painting

• Care must be taken when gluing joints to avoid forming a barrier across the inside of the conduit

What type of finish is suitable for steel conduit in situations where steam or dampness is present?

• Galvanised

• Black enamelled

• Polished

• Rustic