Electrical Testing and Inspection 2

Given the following numbered tests, select the sequence in which these tests should be conducted for a new installation:- 1. functional 2. insulation resistance 3. polarity 4. continuity of final ring conductors 5. continuity of protective conductors:

• 1,3,4,5,2

• 4,5,3,2,1

• 5,4,2,3,1

• 2,3,4,5,1

Table 9A in the On Site Guide gives a value of 19.51 (mohm/m) for a line conductor of 2.5mm2 and a protective conductor of 1.5mm2. What would be the resistance of a circuit 25m in length when wired using these conductors:

• 4.87 ohm

• 487 ohm

• 780 ohm

• 0.487 ohm

Which of the following tests would be carried out 'live':

• insulation resistance

• earth continuity

• prospective fault current

• ring circuit continuity

An approved voltage tester can be used to:

• Establish whether a circuit conductor is live or not

• Determine the effectiveness of a disconnection device

• Measure the resistance of an earth continuity conductor

• Carry out continuity tests

Which of the following does not form part of the earth fault loop impedance

• The phase conductor

• The earth electrode

• The cable armouring

• The neutral within the consumer's installation

An earth fault loop impedance tester should only allow current to flow for:

• 0.4s

• 4.0s

• 40ms

• 400ms

A 100ma RCD protecting a TT installation tested at half the rated tripping current should

• Not operate

• Operate within 50ms

• Operate within 100ms

• Operate within 300ms

Which of the following requirements from GS 38 applies to test equipment which requires more than one test lead?

• The leads must be at least 1m in length

• The leads must have a csa of at least 1.5 mm2

• The leads must be colour coded for identification

• The leads must be permanently attached to the instrument

Which of the following correctly describes the purpose of a continuity of ring final circuit conductors test?

• To confirm the conductors are installed as a complete ring

• To confirm polarity is correct at each point on the circuit

• To determine the R1+R2 value for the final circuit

• To confirm the conductors are the correct csa

A test for continuity of circuit protective conductors is carried out at every point on a circuit. Which of the following describes the purpose of this test?

• To confirm correct polarity

• To confirm the conductors are correct csa

• To determine the R1+R2 value for the circuit

• To confirm exposed conductive parts are connected to the MET