PRACTICE PAPERS: LEVEL 3 UNIT 302

Installation (Buildings and Structures): Inspection, testing and commissioning: Unit 3 – 302

PAPER 11. An Insulation Resistance test needs to be carried out on a commercial DB, way #7 which has a type ‘C’ circuit breaker fitted.

a. State which instrument(s) can be used, the test voltage and current supplied by the meter.b. What equipment is likely to be fitted to the circuit.c. State the precautions need to be taken prior to the test.d. Describe the test. Points: 6

2. Explain the terms:a. Main earthing terminalb. Exposed-conductive-part

Points: 3 each

3. Label this TNS system. Points: 6

4. An earth fault loop impedance test on a lighting circuit, fitted with a fluorescent, is conducted and the 6A type B MCB trips repeatedly. Explain why this may be the case.4(6 points)

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5. Fully label all voltages on this UK generation, transmission and distribution diagram. (6 points)

6. List, in the correct order, all the relevant electrical tests to be carried out for an initial verification on a new installation.

(6 points)

7. a. Using BS 7671, list three locations that need RCD’s of 30mA or less. b. Select suitable RCDs for each of the following electrical installations giving a brief reason for your choice: 1.As a main isolator on a dairy farm which has other RCD’s installed downstream protecting outdoor sockets. 2. General purpose lighting circuit in a domestic property forming part of a TT system. 3. Socket outlet installed in a domestic property that may be used to supply portable equipment outdoors. (6 points)

7. The following test results are obtained when carrying out a test on an electrical installation. The air-conditioning unit is located outside the building and is supplied using p.v.c/s.w.a. multi-core cable. All other circuits are wired using p.v.c. single-core cables in p.v.c. conduit (c.p.c.’s are the same size as the phase conductors). The lighting is a combination of tungsten filament, fluorescent and PIR-controlled exterior high pressure sodium lamps. The earthing system is provided by the sheath of the suppliers cable.

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R1-Y1-B1 16A 3-phase supply to air conditioning unitR2-Y2-B2 40A 3-phase supply to X-ray unitR3 10A supply to PIR controlled external high pressure sodium lampsY3 10A supply to two-way lighting circuit feeding tungsten and fluorescent lightingB3 32A ring final circuit to socket outlets supplied by RCD within split DBR4 32A ring final circuit to socket outlets supplied by RCD within split DB

The measured values of the earth fault loop impedance for EACH circuit are as follows.State whether the values comply with BS 7671 16th / 17TH Edition wiring regulations and the reason for your answer.

9. Name three tests that are performed in an initial verification using a low resistance Ohmmeter. (3 points)

10. Describe the following devices: a. BS 1361 b. BS 88-2.1 c. BS EN 6100 (6 points)11. Before using test equipment list three typical defects or faults that need to be checked. (3 points)

12. a. For an RCD to BS: 4293, state: 1. How frequently the integral test button should be operated 2. The purpose of a manual test 3. The maximum operating time of a 20mA device

(1 point each)

b.If a 20mA RCD is to be used as supplementary protection against direct contact, state the values of the three test currents that should be applied.

(1 point each)

13. For the following test results, state what tests have been performed and which meter has been used: a. 2.8kA b. 5ms c. 999MΩ (6 points)

14. a. Name the earthing system that uses an earth return path which is comprised of: 1. The general mass of earth 2. A separate metallic conductor 3. A combined earth/neutral of the supply cable (3 points)

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b. During an initial verification of an electrical installation, the total earth fault loop impedance Zs of a circuit is measured and found to be less than: Zs = Ze + R1 + R2. Give three possible reasons why this may be found. (3 points)

15. A factory is having a small extension built to cope with increased work. Two new ring final circuits are to be installed, and the existing lighting circuit extended. There are no records of any previous inspection and test. a.With regards to the existing installation what requirements need to be agreed and with whom, before work commences b.What action should be taken before any work, inspection or testing is carried out (6 points)

16. Name three requirements that the Health & Safety executive guidance note GS38 listsas factors that contribute to the safety requirements of:a. Test probes.b. Test leads.(6 points)

17. a. State, in the correct sequence, the first three tests required on a new lighting circuit. b. State, in the correct sequence, the correct name of the test instrument used in (A). (6 points)

PRACTICE PAPER: C&G 2330 LEVEL 3 UNIT 302 REVISION PAPER

PAPAR 2

All questions are worth six marks

UNIT 302: Outcome 1 –Use Safe, Effective and Efficient Working Practices to Complete Electrical Installations

1. List three widely used types of :

a. Wiring systemsb. Wiring enclosure

2. State six stages of preparation necessary before work can be safely carried out on an existing electrical installation.

3. When making an area safe to work in:

a. List three procedures to be taken before commencing workb. Describe the permit to work procedure

4. Explain briefly the use of each of the following types of diagrams or plans:

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a. Circuit diagramsb. Block diagramsc. Site plans

5. When carrying out large contracts

a. List three parties likely to be concernedb. State the purpose of a site record

6. Describe the use of the following in monitoring the progress of a contracta. A bar chartb. A site diaryc. Variation orders

7. State the purpose of each of the following:a. Day work sheetb. Time sheetc. Site diaryd. Site reporte. Variation orderf. Materials list

8. a. List two standard forms of contract used in the construction industry.c. List three conditions that must exist in order to make a contract valid

9. To help establish good customer relations, explain the importance of the following:

a. Dressing smart and appropriatelyb. Pricing your services modestlyc. Keeping the work area clean and tidy

10. a. State the term used to describe a formal document which sets out the terms of an agreement between two parties.c. List two steps that would be involved in making such an agreement between a main

contractor and an electrical contractor

11. Explain the terms:a. Main earthing terminalb. Exposed conductive parts

12. Draw three diagrams to show where the main earthing terminal for an installation would be connected in order to form part of the following:a. TN-C-Sb. TN-Sc. TT

13. a. State how earth fault protection would be provided on socket outlet circuits for a domestic installation forming part of a TT system

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c. Identify three points in an installation that will require a warning notice or label bearing the words ‘Safety Electrical Connections – Do not Remove’.

14. Identify a suitable wiring system for each of the following types of installation, taking into consideration factors such as type of building, usage, environmental conditions, etc.a. Milking parlour sited on a farmb. Domestic dwellings within a housing estatec. Underground supplies to socket outlets sited adjacent to caravan pitches within a caravan

park

15. a. List three categories of switching identified in BS7671.c. Describe briefly the purpose of each category listed in a)

16. Calculate the design current, ignoring the application of diversity factors, for each of the following connected loads in a single-phase installation supplied at 230 V 50Hz.a. Discharge lighting – 10 x 70 W fluorescent luminairesb. GP Tungsten filament lighting – 40 x 100 Wc. Heating 10 kW

17. With reference to the installation and use of Residual current devices (RCD)a. List three situations where RCD protection is requiredb. State the primary function of an RCDc. Describe the term nuisance tripping

18. a. List three different types of overcurrent protective device.b. State three factors which would influence the selection of a protective device

19. A 10 kW 230 V shower is supplied using PVC/PVC multicore cable clipped direct to the surface over a distance of 15m. The circuit is protected by a BSEN 60898 type C circuit breaker. The ambient temperature is 25 deg C. Determinea. Installation reference methodb. Design Currentc. Circuit breaker ratingd. Correction factorse. Minimum cable sizef. Voltage drop

20. Determine the appropriate correction factors to be applied as part of the circuit design calculations for each of the following.a. 3 x MI cables installed on a cable tray and touching each otherb. A 90 0C Thermosetting cable installed in an ambient temperature of 60 0C protected by a BS

1361 devicec. A 2.5mm2 cable totally surrounded by thermal insulation for a length of 400 mm.

21. State one standard voltage for each of the followinga. Grid systemb. Secondary transmission systemc. Supply to industryd. Distribution network

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e. Commercial distributionf. Domestic distribution

Unit 302 Outcome 2 - Select appropriate working methods and use tools, equipment and instruments for installation and commissioning

22. List three requirements of BS 7671 relating to installed electrical equipment to be verified during the inspection process.

23. a. Identify three sources of information used to support the commissioning process.b. Describe the full isolation procedure required prior to working on energised equipment.

24. a. State three reasons why it is essential to commission a new installation prior to signing it over to the client.b. State three essential requirements for test instruments which are to be used during the commissioning process.

25. a. Describe the action to be taken in the event of an installation failing to meet the requirements of BS 7671 following an initial verification and test procedure.b.

26. a. Explain briefly the importance of verification of test instruments before performing tests on an electrical installation.b. State the purpose of each of the following types of test instruments:I. Insulation Resistance testerIi. Tong testerIII. PSCC testerIV. Low resistance ohmmeter

27. Identify three items to be checked during the initial inspection process for a. Steel conduitb. Steel trunking

28. Identify two items to be checked by visual inspection prior to commissioning an installation, each of the followinga. Trunkingb. Cable trayc. Conduit

29. List three relevant documents which may assist the inspection and testing process.

30. a. Arrange the following tests in the sequence required by BS 7671 for an initial verification.

- Polarity

- Earth loop impedance

- Continuity of protective conductors

- Insulation resistance

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b. State the appropriate test instrument, and its range and setting for each of the tests listed in a) above.

31. a. List three documents that must be produced following the inspection and testing of a new electrical installation.b. List the three areas of responsibility which require signatures on the document.

32. a. Explain how the earth loop impedance test is significantly different from the other tests listed in 30 a) above.b. Explain with the aid of a diagram, one method of conducting a test for the continuity of protective conductors.

33. List three checks to be made to verify a test instrument for safety and accuracy prior to use.

34. Describe briefly how to carry out a continuity test of a main equipotential bonding conductor on a new installation prior to the connection of supply.

35. a. State two precautions to be taken during the inspection and testing process.

c. Identify two human senses that may be used during the inspection processd. State two reasons why installed equipment is inspected during an initial verification

36. a. Identify three checks that may be conducted when inspecting a distribution board.b. Identify one possible notice that may be fixed to the origin of the installation within a building.

37. Whilst carrying out an insulation resistance test on a new lighting circuit the test result is unsatisfactory. List three steps which need to be taken.

38. For the following test results, state what tests have been performed and which meter has been used:

a. 2.8 kAb. 5 msc. 999 MΩ

39. An installation has seven circuits. Circuits 1, 4 and 6 have insulation resistances of greater than 200MΩ. . Circuits 2, 3, 5 and 7 have resistance values of 50, 80, 60 and 50 respectively. Calculate the total resistance of the installation.

40. A 100ma general purpose RCD to BS EN 61008 is to be tested to ensure that it operates within specification. What is:

a. The value of the two test currents?b. The maximum permitted operating time when using the larger test current?

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Unit 302 Outcome 1- Use Safe, Effective and Efficient Working Practices to Complete Electrical Installations

PAPER 3

1. When designing and building a new hotel complexa. Draw a block diagram showing relationships and lines of communicationb. List two sets of regulation governing the construction of electrical systems

2. Describe the types of work that need to be undertaken by the electrical contractor whena. Installing equipment and systems on new sitesb. Replacing electrical equipment/systems on existing sitesc. Carrying out work in extensions to existing sites

3. Describe the process involved in producing a contract for the construction of a large commercial building to includea. Clientb. Architectc. Main contractord. Tenderse. Detailed requirements of electrical componentsf. Sub contractors

4. When monitoring the progress of a contract, describe, with the aid of diagrams, the use of a. Bar chartsb. Critical path networks

5. Explain the importance of a. Co-ordinating electrical installation contracts with other trades giving three examplesb. Recognising the implications of variation orders.

6. Explain why it is important that effective lines of communication and good relationships exist betweena. Customer, architect, surveyor, main contractor, sub contractors and local authoritiesb. Sketch a diagram showing lines of communication between the parties listed in a) above.

7. State the standard voltages for

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a. Transmission of electricity from the suppliers to the distribution companiesb. Distribution to large factoriesc. Distribution to light industryd. Local distribution to residential areas

8. In an electrical installation describe the arrangements for a. Isolationb. Switchingc. Over current protection

9. Describe the factors affecting the choice of wiring systems and cable, with reference toa. Over current protectionb. Cables enclosed in thermal insulationc. Cables connected to bus bars operating at higher than normal recommended temperatures for

the cable

10. Describe one advantage and one limitation of the following wiring systemsa. Mineral insulated metal sheathedb. PVC twin and earthc. PVC/SWA cable

11. Describe one advantage and one limitation of usinga. PVC conduitb. Trunking systemc. Cable trays

12. State the condition for the effective termination of cables in terms ofa. Being electrically and mechanically soundb. Ability to carry design currentc. Prevention of corrosion.

13. State the factors affecting the selection of cables conductor size in terms of

a. Design currentb. Voltage dropc. Thermal constraints

14. Where an RCD residual current device) is used as supplementary protection against shock in the absence of a fault (that is, by direct contact), state the a. Operating current requirementsb. Operating timec. Type of test lamp will not operate RCD’s when used to probe between phase and earth

15. State by means of a diagram, the arrangements for connecting a consumer’s main switch for the following supply systemsa. Three phase TNCb. Three phase and neutral TNSc. Single phase TT

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Unit 2 Outcome 2 – Select appropriate working methods and use tools, equipment and instruments for installation and commissioning

16. Identify the purpose and conditions of periodic inspection of electrical installationsa. Damage (i.e. flooding)b. Due to change of use

17. State the purpose of the inspection, testing and commissioning of new electrical installation in terms of a. Compliance with BS7671b. Meeting specificationc. Being safe to use

18. Describe items of visual inspection to be carried out prior to commissioning an electrical installation in terms of a. Main intakeb. Power circuitsc. Lighting circuitsd. Wiring enclosures

19. Identify three factors that will result in a Periodic Inspection being required.

20. Describe how to carry out the following test on the completion of an electrical installationa. Continuity of final ring circuitsb. Insulation resistancec. Earth fault loop impedance.

21. When using test instruments explain the importance of .a. Verifying test instrumentsb. Regular calibrationc. Use of documentary evidence

22. State one type of individual test instrument used for electrical installation testing which would provide readings in the following unitsa. Megohmsb. Milli-secondsc. Ohmsd. kA

23. When carrying out inspection and test procedures on a completed electrical installationa. Describe why it is necessary to carry out continuity tests before insulation resistance testsb. State the precautions to be taken when conducting insulation resistance testsc. State the safety measures when carrying out earth fault loop impedance tests.

24. Describe with the aid of a sketch, an earth electrode resistance test using a proprietary instrument.

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25. Explain with the aid of a diagram, how to carry out an earth loop impedance test on a single phase socket outlet forming part of a TN-C-S system supplied at 230V. The diagram should include the test instrument and show the complete earth fault path using arrows.

26. List six sources of information that will be required for the inspection and testing of a completed electrical installation.

27. Describe the certification process for a completed installation in terms of the a. Electrical Installation Certificateb. Schedule of Inspections

28. The loop values achieved for Step 1 of a ring final circuit test are as followsI. P to P = 0.8 ΩII. N to N =0.8 ΩIII. CPC to CPC = 1.3 Ω

a. Calculate the values expected when testing at all outlets for Step 2 and Step 3 of the test.b. State why the CTC loop reading is higher than that of the live conductors.

29. List six tests to be carried out on a completed installation.

30. At the completion of an installation, it is inspected and tested. State thea. Necessary paperwork to be completed and handed to the customer/clientb. Responsibility of the electrical contractor with regard to periodic inspections c. Responsibility of the electrical contractor who carries out minor additions or alterations to an

installation in terms of completing paperwork.

31. a. List in the correct sequence, the first three tests to be carried out on a newly completed lighting circuitc. State three test currents used to confirm the compliance of a 30mA RCD protecting

equipment located outdoors.

32. If it is necessary to carry out live testing on an electrical systema. Describe how the working area can be made saferb. List two further precautions that should be takenc. Describe the permit to work procedure.

33. At the completion of an electrical installation, it is inspected and tested. State thea. Necessary paperwork to be completed and handed to the customer/clientb. Responsibility of the electrical contractor with respect to periodic inspectionsc. Responsibility of the electrical contractor who carries out minor additions or alterations to an

installation in terms of completing paperwork.

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