Capstone - Testing & Verification

Question 1

Before conducting testing on an electrical installation, what must you do?

Answer 1

A visual inspection

Question 2

Put the following in the order they would be performed during testing:

1- Sub-mains polarity test
2- Verify RCD operation
3- IR test of installation
4- Consumer mains polarity test
5- Final sub-circuit test for polarity and connections
6- Earth resistance test for continuity of main earth conductor
7- Earth fault-loop impedance test
8- Earth resistance test for earthed and equipotentially bonded parts

Answer 2

6
8
3
4
1
5
7
2

Question 3

What are the four steps to isolate and test for de-energised?

Answer 3

1 - Test if switchboard is energised.
2 - Turn off CBs, isolate mains, LOTO.
3 - Test for de-energised on all circuits. Test meter after to prove it still works.
4 - Disconnect main neutral at POS. Disconnect main neutral at neutral bar. Disconnect MEN.

Question 4

What are the four steps to check for earth continuity?

Answer 4

1 - Disconnect possible parallel paths to earth (Hot Water systems). Prepare meter - zero out and test against 0.5 ohm and 1 ohm resistors.
2 - Test continuity to main earth with max of 0.5 ohm. Test continuity between electrode to clamp, clamp to main conductor.
3 - Test continuity of earth to equipotential bonds from earth bar with max of 0.5 ohm.
4 - Test continuity of earth bar to protective earths, max value per table 8.2.

Question 5

What are the four steps to perform Insulation Resistance testing?

Answer 5

1 - Disconnect meter neutral and functional earths. Zero meter and check operation against a 1MΩ resistor.
2 - Test consumer mains.
3 - Test sub-mains.
4 - Test final subcircuits.

Question 6

When doing IR testing on a circuit, what combinations of tests should be done?

Answer 6

Active to earth
Neutral to earth
Active to neutral

Question 7

What is the minimum acceptable value when measuring IR during testing?

Answer 7

1MΩ

Question 8

What setting do you use on an IR tester while doing testing?

Answer 8

500VDC +20% -10%

Question 9

What setting would you use on an IR tester during testing if there are electronics in the circuit which cannot be disconnected?

Answer 9

250VDC

Question 10

What are the five steps when doing polarity testing?

Answer 10

1 - Check continuity using ohmmeter or IR tester at 500 ohm setting. 10 & 5 ohm resistors. 10 ohm goes on active, 5 on neutral, both to earth.
2 - Continuity check across CB both on and off.
3 - Test for interconnections between circuit with other circuits and neutral bar.
4 - Test fault loop impedance

Question 11

How do you test RCD function when de-energised?

Answer 11

Continuity checks across all poles of the device.

Question 12

Where in the AS/NZS 3000 can you find a checklist to guide you for a visual inspection?

Answer 12

Clause 8.2.2 Pages 417-419

Question 13

When testing socket outlets resistance value, you only need to check one socket of a double GPO True or False?

Answer 13

False, you must check both sockets of each double GPO.

Question 14

When testing Insulation Resistance testing on an extra-low voltage circuit, what setting would you use and what is the minimum IR value?

Answer 14

250VDC, 0.5MΩ

Question 15

When testing Insulation Resistance on low-voltage circuits up to 500V, what setting would you use and what is the minimum IR value?

Answer 15

500VDC, 1MΩ

Question 16

When testing Insulation Resistance on circuits above 500V, what setting would you use and what is the minimum IR value?

Answer 16

1000VDC, 1MΩ

Question 17

The functional earth of an RCD shall not be (less than, greater than) what value, on an IR tester?

Answer 17

0.05MΩ

Question 18

Table 8.1 is used when doing a fault-loop impedance test on a circuit that is energised or de-energised?

Answer 18

Energised.

Question 19

Table 8.2 is used when doing fault-loop impedance test on a circuit that is energised or de-energised?

Answer 19

De-energised.