Electrical Safety Quiz

The selection of protective equipment would not include consideration of the effects of:

• overcurrent

• equipment costs

• earth fault current

• undervoltage

The magnitude of current to be carried by a circuit in normal service is:

• overload current

• short circuit current

• protective conductor current

• design current

Which of the following is not recognised as a source for a safety service?

• storage batteries

• the normal DNO supply

• primary cells

• independent generator sets

What is the maximum rating of an RCD providing additional protection to a BS 1363 socket-outlet used by ordinary persons?

• 10mA

• 30mA

• 100mA

• 300mA

A 16A BS EN 60898 Type C circuit breaker used to protect a three-phase reduced low voltage circuit is subject to a maximum earth fault loop impedance value of:

• 0.65Ω

• 0.75Ω

• 0.33Ω

• 0.38Ω

In order to protect against burns, a non-metallic electrical part intended to be touched (but not handheld) should not attain a surface temperature in excess of:

• 65°C

• 70°C

• 80°C

• 90°C

What is the maximum time a 16.0 mm² conductor having a ‘k’ factor of 115 can withstand a fault current of 13 kA?

• 0.01 s

• 0.02 s

• 0.14 s

• 2.26 s

The notice relating to an RCD requires the device to be operated via its test button:

• monthly

• quarterly

• half-yearly

• annually

The rating factor for a cable surrounded by thermal insulation for 200 mm is:

• 0.88

• 0.78

• 0.63

• 0.51

Where a Type 1 SPD is installed near the origin of an installation and is not protected by an OCPD, the minimum cross-sectional area of an SPD connecting conductor is:

• 4.0 mm²

• 6.0 mm²

• 10.0 mm²

• 16.0 mm²