18th Edition appendices mock 3

What does BS 1361 relate to?

• a)        MCBs
• b)       Re-wireable fuses
• c)        Low-voltage cartridge fuses
• d)       Lightning protection

What is the highest-rated fuse to BS 88-3 that has a disconnection time of 0.1 seconds when carrying 820 amps?

• a)        32 amps
• b)       45 amps
• c)        63 amps
• d)        80 amps

With reference to energy efficiency systems, consideration should be given to improving load power factor to?

• a)    Reduce the energy available
• b)    Reduce the power available
• c)     Reduce thermal losses in the wiring
• d)    Reduce the external loop impedance Ze

For which of the following types of work would it not be permissible to use a minor electrical installation works certificate?

• a)        The addition of a socket-outlet to an existing circuit
• b)        The addition of a lighting point to an existing circuit
• c)        The replacement of a light switch
• d)        The replacement of a distribution board

When measuring the resistance / impedance of floors and walls a test electrode comprising of a metallic tripod is used, over what approximate area should the test be conducted?

• a)                  600 mm2
• b)                  700 mm2
• c)                  800 mm2
• d)                  900 mm2

A single-phase lighting circuit is installed using two-core armoured 10 mm2 70°C thermoplastic insulated cable. The luminaires draw 25 Amps from the 230-volt a.c. supply. What will be the voltage drop in a 50m length of cable?

• a)        2.55 volts
• b)        3.25 volts
• c)        4.75 volts
• d)        5.50 volts

What type of equipment is most likely to produce significant harmonic currents?

• a)       Sodium lighting
• b)        Variable speed drive motors
• c)        Transformers
• d)       Electric heating elements

What is the external influence code for 'presence of water'?

• a)            AB
• b)        AC
• c)         AD
• d)           AE

With reference to energy efficiency systems, what is not required to be considered by the designer of the installation?

• a)     Load energy profile
• b)     Availability of local generation
• c)      Reduction of energy losses in the electrical installation
• d)     The tariff structure offered by the network generating companies

What is the maximum trip time for a general purpose, non-delay 100 mA RCD to BS EN 61008-1, when subjected to a load equal to its rating?

• a)             50 ms
• b)        100 ms
• c)         300 ms
• d)        500 ms