TNS earthing systems use the

• supply cable armour
• earth electrode
• neutral
• transformer

RCD's that are used to protect socket outlet are rated at

• 30 A
• 30 mA
• 3 mA
• 300 mA

The symbol Ze is associated with

• total loop impedance
• external suppliers earth loop impedance
• R1
• R2

A TNCS earthing system, changes Line to c.p.c faults to

• Line to neutral faults
• Line to Line faults
• Line to c.p.c faults
• c.p.c to Line faults

The symbol for Total earth loop impedance is?

• Zs

• Ib

• Iz

• Ze

The insulation material in mineral insulated cable is

• manganese oxide

• magnesium dioxide

• manganese dioxide

• magnesium oxide

What is the maximum percentage of trunking that can be filled with cable:

• 35%

• 45%

• 55%

• 65%

Which MCB will disconnect in the shortest time?

• Type C
• Type D
• Type B
• RCD

What is the BS number for a MCB?

• BS 60898
• BS 1265
• BS 61009
• BS 60947

Name the extraneous conductive part

• Socket cover
• PVC switch
• Central heating pipework
• Cable tray