Test Procedures

Question 1

Earth continuity for main protective bonding

Answer 1

1. Isolate and make safe the supply
2. Disconnect the main protective bonding conductors from 1 side
3. Test the leads of the continuity tester and note the value
4. Connect one lead to the MET and the other lead to the last point of the main protective bonding conductor
5. Record the highest result (remove the value of the test leads)
6. The value should be found in table I1
7. Reconnect the main protective conductors and the supply

Question 2

Continuity of protective conductor (method 2)

Answer 2

1. Isolate and make safe the supply
2. Test the leads of the continuity tester and note the value
3. Connect 1 lead to the MET, connect the wander lead to all earth terminal points
4. Record the highest value in the R2 section of the test sheet
5. Reconnect the supply

Question 3

Earth continuity of protective conductor (method 1 r1+r2)

Answer 3

1. Isolate and make safe the supply
2. Test the leads of the continuity tester and note the value
3. Install a link between the MET and the circuit breaker of the circuit to be tested
4. Test all points between the earth terminal and the line conductor
5. Record the highest result in the r1+r2 section of the test sheet
6. Remove the link
7. Switch the supply back on

Question 4

Continuity of ring final circuit (step 1)

Answer 4

1. Isolate and make safe the supply
2. Test the leads of the continuity tester and note the value
3. Remove cables from terminations
4. Test between L-L, N-N, CPC-CPC (L-L & N-N should be the same, CPC will be 1.67x lower)

Question 5

Continuity of ring final circuit (step 2)

Answer 5

1. Connect the line out to the neutral in and neutral out to line in
2. Using the continuity tester, test between the line and neutralof every socket (all values should be the same +/- 0.05ohms)

Can show incorrect polarity, a spur can increase the impedence, ring circuit within a ring circuit, should equal L-L+N-N/4

Question 6

Continuity of ring final circuit (step 3)

Answer 6

1. Connect the line out to the CPC in and CPC out to line in
2. Using continuity tester, test between line and CPC of every socket, all values should be the same (+/-0.05ohms)

Can show incorrect polarity, a spur can increase the impedence, ring circuit within a ring circuit, should equal L-L+CPC-CPC/4

Question 7

Insulation resistance test

Answer 7

1. Isolate and make safe the supply
2. All circuit breakers for circuits are on
3. All light switches are on
4. All lamps, neon lamps, motors, electrical accessories and sensitive equipment are off or removed
5. Set the IR tester to 500v DC
6. Place 1 lead on the earth terminal and the other on a live terminal and test the circuit, record in CPC-L
7. Place the lead from the live terminal to the neutral bar and test, record in CPC-N
8. Place the lead from the earth terminal to the live terminal and test, record in L-N
9. Remove the test leads, connect electrical accessories, motors etc
10. Reconnect the supply

Question 8

Results of IR test

Answer 8

All tests must be 1Mohm of higher, lowest value must be recorded.
Problems: corrosion, crushed cables, damp ends, water damage, short circuits, loose connections, insulations cut.

Question 9

IR for 3ph

Answer 9

1. Isolate and make safe the supply
2. All light switches are off
3. All lamps, electrical accessories etc are off or disconnected
4. Set IR tester to 500v DC
5. Place one lead on the earth bar then test between L1, L2, L3 and N, record the lowest result in CPC-L and CPC-N
6. Place one lead on the neutral bar and test between L1, L2, L3, record lowest value in N-L
7. Place one lead on L1 then test between L2, L3, record the lowest value in L-L
8. Place one lead on L2 and test between L3, record lowest value in L-L
9. Reconnect the motor and/or sensitive equipment
10. Switch on the supply

Question 10

Earth Fault Loop Impedence Test (Zs)

Answer 10

1. Plug in earth fault loop impedence test
2. Press the button
3. Record the highest result, all sockets should be tested, values must be the same or lower than those in table 41.2-41.4

Question 11

Prospective Fault Current

Answer 11

1. At the main supply connect the tester to the line, neutral and earth terminals
2. Press the button
3. Record the highest result

The breaking capacity of the protective device must be higher than the test value otherwise it won’t be able to stop the fault current

Question 12

RCD Test

Answer 12

1. Connect the tester to the line, neutral and CPC on the load side
2. Press the button
3. Record the time, RCD must trip in 300ms or less at rating of the RCDx1

Question 13

IR test for sensitive equipment

Answer 13

1. Disconnect the supply
2. Set to 250v
3. Link the live and neutral and test to CPC