Unit 203 OSG questions - Use your onsite guide for answers

identify the type of emergency light fitting the remains lit continuously

• sustained

• contained

• maintained

• non maintained

identify the rating of an RCD used for additional protection for buried cables in walls.

• 100mA

• 20mA

• 13A

• 30mA

Answer explanation

7.3.2

when applying DIVERSITY to discharge lighting (such as fluorescent lamps), identify the multiplication factor that should be applied to the lamp wattage

• 2

• 1.8

• 10

• 5.5

Answer explanation

Table A1 (note 2)

identify the rated short-circuit capacity of a BS88-6 device at 240v, as detailed in the On Site guide

• 16kA

• 33kA

• 16.5kA

• 31.5kA

Answer explanation

Table 7.2.7(i)

how can long runs of pvc conduit be installed to reduce the prospect of distorting and buckling due to large changes in ambient temperature.

• greater distances between saddles
• pvc conduit must not be installed in these environments
• regular through-boxes are used throughout the run
• use expansion couplers

identify the maximum 'measured' Zs value allowed for a type B 16A circuit breaker to BSEN60898, as detailed in the On Site guide

• 3.5 ohms

• 1.09 ohms

• 2.2 ohms

• 1.58 ohms

Answer explanation

Table B6

What is the recommended maximum earth fault loop impedance for a TT system

• 21Ω

• 79Ω

• 200Ω

• 0.8Ω

Answer explanation

4.9

You need to drill a hole in a joist to run a cable under a floor, what is the maximum diameter of the hole?

• 0.3 x the joist depth

• 0.2 x the joist depth

• 0.25 x the joist depth

• it is not permitted to drill joists

Answer explanation

7.3.1

if an overcurrent occurs in an otherwise healthy circuit, this would be called ........

• an open circuit
• an earth fault
• a short circuit
• an overload

when applying DIVERSITY to a water heater in a small shop, identify the percentage of total current demand allowed if the heater is thermostatically controlled

• 0.75

• not allowed

• 0.9

• 0.66