PRACTICE PAPERS: LEVEL 3 UNIT 302
Installation (Buildings and Structures): Inspection, Inspection, testing and commissioning: Unit 3 – 302 PAPER 1 1. An Insula Insulatio tion n Resis Resistan tance ce test test need needss to be carri carried ed out out on on a comm commerci ercial al DB, DB, way way #7 which has a type ‘C’ circuit breaker fitted.
a. b. c. d.
2. a.
State State whic which h instr instrume ument( nt(s) s) can can be used, used, the the test test volt voltage age and curren currentt suppl supplied ied by the the meter. What equipment is likely to be fitted to the circuit. State the precautions need to be taken prior to the test. Describe the test. Points: 6
Explain the terms: Main earthing terminal b. Exposed-conductive-part Points: 3 each
3.
Label this TNS system. Points: 6
4.
An eart earth h fault fault loop loop impe impedan dance ce test test on a lighti lighting ng circu circuit, it, fitte fitted d with with a fluor fluoresc escent ent,, is conducted and the 6A type B MCB trips repeatedly. Explain why this may be the case.
4 (6 points) 1
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. R1-Y1-B1 16A 3-phase supply to air conditioning unit 2
R2-Y2-B2 40A 3-phase supply to X-ray unit R3 10A supply to PIR controlled external high pressure sodium lamps Y3 10A supply to two-way lighting circuit feeding tungsten and fluorescent lighting B3 32A ring final circuit to socket outlets supplied by RCD within split DB R4 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 16 th / 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) Before using test equipment list three typical defects or faults that need to be checked. (3 points)
11.
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) b. During an initial verification of an electrical installation, the total earth fault loop 3
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 lists as 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 systems b. 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:
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a. List three procedures to be taken before commencing work b. Describe the permit to work procedure
4.
Explain briefly the use of each of the following types of diagrams or plans:
a. Circuit diagrams b. Block diagrams c. Site plans
5.
When carrying out large contracts
a. List three parties likely to be concerned b. State the purpose of a site record
6.
Describe the use of the following in monitoring the progress of a contract a. A bar chart b. A site diary c. Variation orders
7.
State the purpose of each of the following: a. Day work sheet b. Time sheet c. Site diary d. Site report e. Variation order f. 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
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9.
To help establish good customer relations, explain the importance of the following:
a. Dressing smart and appropriately b. Pricing your services modestly c. 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 terminal b. 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-S b. TN-S c. 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
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 farm
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b. Domestic dwellings within a housing estate c. 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 luminaires b. GP Tungsten filament lighting – 40 x 100 W c. Heating 10 kW
17. With reference to the installation and use of Residual current devices (RCD) a. List three situations where RCD protection is required b. State the primary function of an RCD c. Describe the term nuisance tripping
18. a. b.
List three different types of overcurrent protective device. 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. Determine a. Installation reference method b. Design Current c. Circuit breaker rating d. Correction factors e. Minimum cable size f. Voltage drop
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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 other C Thermosetting cable installed in an ambient temperature of 60 0C protected by a BS 1361 device
b. A 90
0
c. A 2.5mm2 cable totally surrounded by thermal insulation for a length of 400 mm.
21.
State one standard voltage for each of the following a. Grid system b. Secondary transmission system c. Supply to industry d. Distribution network e. Commercial distribution f. 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. b.
24. a.
Identify three sources of information used to support the commissioning process. Describe the full isolation procedure required prior to working on energised equipment.
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
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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 tester
Ii.
Tong tester
III.
PSCC tester
IV.
Low resistance ohmmeter
27. Identify three items to be checked during the initial inspection process for a. Steel conduit b. Steel trunking
28. Identify two items to be checked by visual inspection prior to commissioning an installation, each of the following a.
Trunking
b. Cable tray c.
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 9
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.
c.
State two precautions to be taken during the inspection and testing process.
Identify two human senses that may be used during the inspection process
d. 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 kA 10
b. 5 ms c. 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 i t 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?
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 complex
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a. Draw a block diagram showing relationships and lines of communication b. 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 when
a. Installing equipment and systems on new sites b. Replacing electrical equipment/systems on existing sites c. 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 include a. Client b. Architect c. Main contractor d. Tenders e. Detailed requirements of electrical components f. Sub contractors
4. When monitoring the progress of a contract, describe, with the aid of diagrams, the use of
a. Bar charts b. Critical path networks
5. Explain the importance of
a. Co-ordinating electrical installation contracts with other trades giving three examples b. Recognising the implications of variation orders.
6. Explain why it is important that effective lines of communication and good relationships exist
between a. Customer, architect, surveyor, main contractor, sub contractors and local authorities
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b. Sketch a diagram showing lines of communication between the parties listed in a) above.
7. State the standard voltages for
a. Transmission of electricity from the suppliers to the distribution companies b. Distribution to large factories c. Distribution to light industry d. Local distribution to residential areas
8. In an electrical installation describe the arrangements for
a. Isolation b. Switching c. Over current protection
9. Describe the factors affecting the choice of wiring systems and cable, with reference to
a. Over current protection b. Cables enclosed in thermal insulation c. 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 systems
a. Mineral insulated metal sheathed b. PVC twin and earth c. PVC/SWA cable
11. Describe one advantage and one limitation of using
a. PVC conduit b. Trunking system c. Cable trays
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12. State the condition for the effective termination of cables in terms of
a. Being electrically and mechanically sound b. Ability to carry design current c. Prevention of corrosion.
13. State the factors affecting the selection of cables conductor size in terms of
a. Design current b. Voltage drop c. 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 requirements b. Operating time c. 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 systems a. Three phase TNC b. Three phase and neutral TNS c. Single phase TT
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 installations
a. Damage (i.e. flooding) b. Due to change of use 14
17. State the purpose of the inspection, testing and commissioning of new electrical installation in
terms of a. Compliance with BS7671 b. Meeting specification c. 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 intake b. Power circuits c. Lighting circuits d. 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 installation
a. Continuity of final ring circuits b. Insulation resistance c. Earth fault loop impedance.
21. When using test instruments explain the importance of .
a. Verifying test instruments b. Regular calibration c. Use of documentary evidence
22. State one type of individual test instrument used for electrical installation testing which would
provide readings in the following units a. Megohms b. Milli-seconds 15
c. Ohms d. kA
23. When carrying out inspection and test procedures on a completed electrical installation
a. Describe why it is necessary to carry out continuity tests before insulation resistance tests b. State the precautions to be taken when conducting insulation resistance tests c. 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.
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 Certificate b. Schedule of Inspections
28. The loop values achieved for Step 1 of a ring final circuit test are as follows I.
P to P = 0.8 Ω
II.
N to N =0.8 Ω
III.
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. 16
30. At the completion of an installation, it is inspected and tested. St ate the
a. Necessary paperwork to be completed and handed to the customer/client b. 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 circuit
c. 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 system
a. Describe how the working area can be made safer b. List two further precautions that should be taken c. Describe the permit to work procedure.
33. At the completion of an electrical installation, it is inspected and tested. State the
a. Necessary paperwork to be completed and handed to the customer/client b. Responsibility of the electrical contractor with respect to periodic inspections c. Responsibility of the electrical contractor who carries out minor additions or alterations to an installation in terms of completing paperwork.
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