Testing And Inspection

Question 1

Sequence of tests?

Answer 1

Dead (4)
Continuity of protective devices
Continuity of ring final
Insulation resistance

Live (3)
Polarity
Prospective fault current
RCD test

Question 2

Continuity of protective conductors

Answer 2

(Either null leads or record resistance and subtract from reading)

Set tester to continuity.

1. Link out between live and earth at board
2. Test between Live and Earth at board

Record readings

Ring r1+r2
Use socket tester with live and earth leads
Record reading

Question 3

Continuity or ring final

Answer 3

Set to continuity

1. Disconnect L,N,E at the board and flag in and out
2. Then test across L-L, N-N, E-E and record readings.

Then with connector block connect in L to out E and reversed, then using a socket tester plug into each outlet to prove polarity. Killing 2 birds with one stone.

Question 4

Insulation resistance

Answer 4

Remove all lamps and LEDs/neons before test and all switches should be open

Global
1. Set to insulation resistance and test between L on Main circuit breaker and neutral bar

Individual circuit
1. locate neutral cable on bar for circuit you are testing
2. Put crocodile clip on neutral cable and use prong to test on L outgoing side of circuit breaker.
>500

Question 5

Polarity

Answer 5

When testing for continuity of ring, also plug socket tester in to prove polarity.

Question 6

Prospective fault current

Answer 6

See earth fault loop impedance

Question 7

Earth fault loop impedance

Answer 7

Zs = ze + (R1+R2)

For your Ze value, set to hi current
Test incoming supply live with incoming earth

PFC will be given below on fluke tester

Question 8

RCD test

Answer 8

Set to RCD time

Pull slider down and turn breaker on
Test across live - earth and record value for highest 5x either 0° or 180°

Question 9

Safe isolation

Answer 9

Lock off isolator for DB
Test leads in proving unit
Test across L-N,L-EN-E.
Once proved dead put back into proving unit

Question 10

Earth fault loop impedance of RCBO?

Answer 10

No trip

Question 11

Earth fault loop impedance of MCB?

Answer 11

Hi current

Question 12

How to find Zs of ring?

Answer 12

Turn breaker on and use socket lead and test on no trip

Question 13

Short circuit?

Answer 13

Insulation resistance

Conductors touching

Question 14

Open circuit?

Answer 14

Continuity

Break in circuit

Question 15

What tester setting for Ze?

Answer 15

Hi current