2392

Level 2 Certificate in

Fundamental Inspection,

Testing and Initial

Verification

Workbook

PRE-ATTENDANCE

REVISION V1

Welcome

This booklet is designed to outline the areas that you will study when you complete the 2392 qualification.

Throughout your time in centre you will have a qualified assessor there to help and advise you.

We want you to achieve the best possible benefits from your time in centre, therefore before attending we would like you to revise by carrying out the work detailed in this booklet. Studying this workbook will ensure that you are properly prepared before attending centre and therefore help you achieve the best possible results from your time in centre.

Please remember that you should not carry out any electrical practical work unless you are in class with one of our qualified assessors.

We very much look forward to welcoming you at the centre.

SmartScreen Level 2 Certificate in Fundamental Inspection, Testing and Initial Verification Handout: Pre-verification information

2392-10 Fundamental Initial Verification Handout: Information required prior to verification (session 1)

Assessment of general characteristics

Before commencing to carry out an initial verification of an installation, certain information and documentation must be available, such as

• Maximum demand• Details of number of supply live conductors• Earthing arrangements (TT, TN-S, TN-C-S)• Supply voltage, frequency, current, Ze, etc.• Drawings charts etc of installation details (type and composition of circuits, method of

fault protection, protective and switching devices, equipment vulnerable to tests)• External influences • Compatibility• Maintainability

With regards to external influences, Appendix 5 of BS 7671 gives alpha-numeric codes for environmental conditions such as presence of water or foreign bodies etc.

These codes fall in line with the IP codes which indicate how well an enclosure can protect against the ingress of water and solid foreign bodies.

SmartScreen Level 2 Certificate in Fundamental Inspection, Testing and Initial Verification Handout: Certificates and test instruments

2392-10 Fundamental Initial Verification Handout: Certificates and test instruments (session 4)

There are two types of inspection and test 1. Initial Verification for new work or additions or alterations2. Periodic Inspection for existing installations

Certification Initial Verification requires an Electrical Installation Certificate (EIC). Periodic inspection requires a Periodic Inspection Report (PIR).

Both the EIC and the PIR must be accompanied by a Schedule of Inspections and a Schedule of Test Results.

For an alteration to a single circuit of an existing installation, which does not include a new circuit, a Minor Electrical Installation Works Certificate may be issued.

For Initial Verification the common tests, the appropriate instruments and the test sequence are:

1. Continuity of protective conductors – Low resistance ohmmeter2. Continuity of ring final circuits – Low resistance ohmmeter3. Insulation resistance – Insulation resistance tester4. Polarity – Low resistance ohmmeter5. Earth electrode resistance – Earth electrode resistance tester6. Earth fault loop impedance – Earth fault loop impedance tester7. Prospective fault current – Prospective fault current tester8. RCD operation – RCD tester

The same tests and instruments apply to Periodic Inspection but not necessarily carried out in the same sequence.

SmartScreen Level 2 Certificate in Fundamental Inspection, Testing and Initial Verification Handout: Continuity of CPC

2392-10: Certificate in Fundamental Inspection, Testing and Initial Verification Handout: CPC continuity (session 5)

Suggested test procedure

CPC continuity

• Inform personnel/client, that test is to take place• Isolate supply to circuit• Make safe• Disconnect line and cpc conductors at distribution board and link together• Use a low resistance ohmmeter• Test between line and cpc terminals at each point on the circuit• Record the result obtained at the farthest point of the circuit (R1 + R2)• Re-instate the system• Compare this reading with design value or, if not available, with a calculated value

obtained as shown in the example.

Example

(R1 + R2) for a 10m length of 2.5mm2 + 1.5mm2 twin and cpc cable measured at 20 oC

= =0.195 Ω×+1000

1012.1)(7.41

SmartScreen Level 2 Certificate in Fundamental Inspection, Testing and Initial Verification Handout: Insulation resistance

2392-10: Certificate in Fundamental Inspection, Testing and Initial Verification Handout: Insulation resistance (session 6)

Please see below a suggested test procedure and minimum acceptable values.

Suggested test procedure

• Inform personnel/client, that test is to take place• Isolate supply to installation/circuit• Disconnect electronic equipment, if not possible only test between lives and earth• Remove neons, capacitors etc that may give misleading results• Remove all lamps and accessories• All switches ‘on’, fuses ‘in’, cb’s ‘on’• Use an insulation resistance tester set on (required voltage)• Test between each live conductor and then between each live conductor and earth

(except where electronics etc cannot be disconnected then only between livesconnected together an earth)(Where there is two-way switching, operate switches and re-test)

• Record and interpret results• Re-instate the system

Minimum values

Circuit nominal voltage Volts

Test voltage (dc) Volts

Minimum value MΩ

SELV and PELV 250 ≥0.5 Up to 500V 500 ≥1.0 Over 500V 1000 ≥1.0

SmartScreen Level 2 Certificate in Fundamental Inspection, Testing and Initial Verification Handout: Earthing systems

2392-10: Certificate in Fundamental Inspection, Testing and Initial Verification Handout: Earthing Systems (session 8)

The diagram illustrates the three earthing systems commonly encountered.

TN-S (Ze=0.8Ω)

E

Mass of earth

Return path

Metallic return path Cable sheath

T.T (Ze=21Ω

TN-C-S (Ze=0.35Ω )

PEN conductorLink

L

N

FaultTransformer winding

Earthed neutral

Fault current I

cpc

MET

THE EARTHING SYSTEMS Earth fault loop path

Exposed conductive part

Protective device

The earthing conductor

SmartScreen Level 2 Certificate in Fundamental Inspection, Testing and Initial Verification Handout: Use of RCDs

2392-10: Certificate in Fundamental Inspection, Testing and Initial Verification Handout: Use of RCDs (session 9)

Requirements for RCD protection

30mA • All socket outlets rated at not more than 20A and for unsupervised general use• Mobile equipment rated at not more than 32A for use outdoors• All circuits in a bath/shower room• Preferred for all circuits in a TT system• All cables installed less than 50mm from the surface of a wall or partition (in the safe

zones) if the installation is un-supervised, and also at any depth if the if the construction ofthe wall or partition includes metallic parts

• In zones 0, 1 and 2 of swimming pool locations• All circuits in a location containing saunas etc• Socket outlet final circuits not exceeding 32A in agricultural locations• Circuits supplying Class II equipment in restrictive conductive locations• Each socket outlet in caravan parks and marinas and final circuit for houseboats• All socket outlet circuits rated not more than 32A for show stands etc• All socket outlet circuits rated not more than 32A for construction sites (where reduced

low voltage etc is not used)• All socket outlets supplying equipment outside mobile or transportable units• All circuits in caravans• All circuits in circuses etc• A circuit supplying Class II heating equipment for floor and ceiling heating systems

500mA • Any circuit supplying one or more socket outlets of rating exceeding 32A, on a construction

site

300mA • At the origin of a temporary supply to circuses etc• Where there is a risk of fire due to storage of combustible materials• All circuits (except socket outlets) in agricultural locations

100mA • Socket outlets of rating exceeding 32A in agricultural locations

Where loop impedances are too high, RCD ratings can be calculated.

SmartScreen Level 2 Certificate in Fundamental Inspection, Testing and Initial Verification Worksheet: CPC continuity

2392-10: Certificate in Fundamental Inspection, Testing and Initial Verification Worksheet: CPC continuity (session 5)

Candidate’s name: ......................................................

Instructions: The following (R1 + R2) values were recorded for six radial circuits, wired in flat twin with CPC cable, installed in a new installation.

Circuit 1 Circuit 2 Circuit 3 Circuit 4 Circuit 5 Circuit 6

Length 5m 8m 10m 15m 10m 15m

Line/cpc csa mm2 6.0 / 2.5 4.0 / 1.5 2.5 / 1.5 2.5 / 1.5 1.0 / 1.0 1.0 / 1.0

Measured value 0.05Ω 0.12Ω 0.35Ω 0.2Ω 0.3Ω 0.5Ω

Line/cpc csa mm2 mΩ/m at 20oC 6.0 /2.5 10.49 4.0 / 1.5 16.71 2.5 / 1.5 19.51 1.0 / 1.0 36.2

For each circuit given the tabulated values of resistance shown above: 1. What would be the calculated values of R1 + R2?2. How do these compare with the measured values?3. Suggest reasons for any high measured values.

SmartScreen Level 2 Certificate in Fundamental Inspection, Testing and Initial Verification Worksheet: CPC continuity

Mark out of 5 for correct formula = ............ Mark out of 12 for correct calculation (2 each) = Mark out of 3 for correct reason/s = ............

Total out of 20 =

SmartScreen Level 2 Certificate in Fundamental Inspection, Testing and Initial Verification Worksheet: Ring final circuit continuity

2392-10: Certificate in Fundamental Inspection, Testing and Initial Verification Worksheet: Ring final circuit continuity (session 5)

Candidate’s name: ......................................................

Instructions: Complete the chart by identifying whether the test results for each socket on the ring are satisfactory or not, giving reasons for your comments.

TEST 1 L1 to L2 N1 to N2 cpc1 to cpc2 0.81Ω 0.80Ω 1.33Ω

TEST 2 SOCKET L to N

Ω L to cpc Ω

OK YES

OK NO

REASON/S

A 0.4 0.55

B 0.39 0.72

C No reading 0.54

D 0.66 0.78

E 0.41 0.53

F No reading No reading

G 0.6 0.52

H 0.4 No reading

Mark out of 18 for identification of hazards = ............

Mark out of 18 for identification of PPE = ............

SmartScreen Level 2 Certificate in Fundamental Inspection, Testing and Initial Verification Worksheet: Insulation resistance

2392-10: Certificate in Fundamental Inspection, Testing and Initial Verification Worksheet: Insulation resistance (session 6)

Candidate’s name: ......................................................

Instructions The following line to earth values were recorded for six circuits in an installation. What would be the expected overall value when measured at the origin and what action should be taken, if any?

Circuit 1 Circuit 2 Circuit 3 Circuit 4 Circuit 5 Circuit 6 Resistance values in

MΩ 25 5 10 20 25 15

Mark out of 10 for correct formula = Mark out of 5 for correct figures in formula = Mark out of 5 for correct answer =

Total out of 20 =

SmartScreen Level 2 Certificate in Fundamental Inspection, Testing and Initial Verification Worksheet: Polarity

2392-10: Certificate in Fundamental Inspection, Testing and Initial Verification Worksheet: Polarity (session 7)

Candidate’s name: ......................................................

Instructions 1. State three reasons for conducting a polarity test on a de-energised installation.

Reason 1

Reason 2

Reason 3

2. State the instrument to be used.

3. State why another polarity check needs to be made after the supply is restored.

4. State the instrument to be used.

1. Mark out of 12 (for each correct answer) = 2. Mark out of 2 for correct instrument = 3. Mark out of 3 for correct reason = 4. Mark out of 3 for correct instrument =

Total out of 20 =

SmartScreen Level 2 Certificate in Fundamental Inspection, Testing and Initial Verification Worksheet: Earth fault loop impedance

2392-10: Certificate in Fundamental Inspection, Testing and Initial Verification Worksheet: Earth fault loop impedance (session 8)

Candidate’s name: ......................................................

Instructions 1. The following measured values of loop impedance were recorded for six circuits in aninstallation. Each circuit is protected by a BS EN 60898 type B cb. Referring to the maximumtabulated values given, show by calculation if these measured values are acceptable.

2. For any circuit that does not comply, suggest a method of overcoming the situation.

Measured loop impedance values in Ω

Circuit 1 Circuit 2 Circuit 3 Circuit 4 Circuit 5 Circuit 6 40A 32A 32A 20A 16A 6A

0.5 1.25 0.96 1.62 2.0 7.3

Maximum tabulated values of loop impedance Ω

1.15 1.44 1.44 2.3 2.87 7.67

SmartScreen Level 2 Certificate in Fundamental Inspection, Testing and Initial Verification Worksheet: Earth fault loop impedance

Mark out of 4 for correct method = Mark out of 12, 2 for each correct answer = Mark out of 4 for correct remedial action =

Total out of 20 =

SmartScreen Level 2 Certificate in Electrotechnical Technology Worksheet: RCD testing

2392-10: Certificate in Fundamental Inspection, Testing and Initial Verification Worksheet: RCD testing (session 9)

Candidate’s name: ......................................................

Instructions With regards to testing RCDs

1. How often should the integral test button be operated?2. What is the purpose of the test in 1 above?3. List the relevant applied test currents and maximum disconnection times for RCDs rated at

a) 20mAb) 30mAc) 100mA

Mark out of 2 for correct frequency = ............ Mark out of 2 for correct purpose =............ Mark out of 6 for a) correct values (2 each) =............ Mark out of 6 for b) correct values (2 each) =............ Mark out of 4 for a) correct values (2 each) =............

Total out of 20 =............

Please make sure you thoroughly study all the necessary workbooks before you contact us to request a date to attend centre for the practical

elements relating to the workbooks.