FINAL-ER 42 Electrician Regulations Answer Schedule

Transcription

1 FINAL-ER 42 Electrician Regulations Answer Schedule Notes:1. (1 mark) means that the preceding statement/answer earns 1 mark. 2. This schedule sets out the expected answers to the examination questions. The marker can exercise their discretion and decide on the overall accuracy of any answer that is presented in the candidate s own words. 3. Symbols and terms - alternatives Power W or P Voltage V or E or U Phase Active Question 1 Marks Reference Marking notes (a) Any TWO of: The fittings are impaired ESR 20(2)(a) Fittings are installed in such a way that any designed cooling conditions are impaired. Fittings that cause or are subject to high temperatures are placed in such a position so as to create a source of ignition. There is insufficient space, access and lighting to operate, maintain, repair, test or inspect the fittings in a safe manner If the Secretary believes on reasonable grounds that a fitting. is electrically unsafe, the Secretary may prohibit the fitting being installed. ESR 20(2)(e) ESR 20(2)(f) ESR 20(2)(i) ESR 87(1) FINAL-ER 42 ANSWERS 25 JUNE

2 Question 1 Marks Reference Marking notes (b) Any TWO of: The name of the person so notifying and the place at which that person may be contacted (including where possible a telephone number and facsimile number): The place, date, and time of the accident: A complete description of the accident: A description of any injuries, damage, or losses resulting from the accident: Where known, the names and contact information of any witness, investigator at the scene, or other person who could provide cogent information on the accident: Possible causative factors (if any are known): Any resuscitation applied, including the method, the length of time applied, the reason for discontinuing, and the person that applied the resuscitation: Any associated equipment involved, including the type, whether or not it operated correctly, and any reasons why it did not operate correctly: The condition of the associated equipment involved, including its age: Where known, the name, age, sex, occupation, and residential address of the victim. ESR 112 (1) FINAL-ER 42 ANSWERS 25 JUNE

3 Question 1 Marks Reference Marking notes (c) ANY ONE of: Where unexpected opening of the circuit could cause a danger greater than overload. Provided that the conductor is not situated in a location presenting a fire risk or a risk of explosion. Provided that the conductor is not situated where requirements for special installations and locations specify different conditions and the conductor is located on the load side of a change in current-carrying capacity that is effectively protected against overload by a protective device placed on the supply side of the origin of the conductor. Provided that the conductor is not situated where requirements for special installations and locations specify different conditions and the conductor supplies electrical equipment that is not capable of causing an overload current and the conductor has no branch circuits or socket outlets connected between the origin of the conductor and the electrical equipment. Provided that the conductor is not situated where requirements for special installations and locations specify different conditions and the conductor is provided for installations for telecommunication, control, signalling, and the like : (d) Faults between live conductors (1 mark) Against voltages imported into the electrical earthing system through the supply system neutral conductor (1 mark) (e) Any ONE of: It must be outside and not above a classified zone (e) FINAL-ER 42 ANSWERS 25 JUNE

4 Question 1 Marks Reference Marking notes It must be outside a classified zone (f) Any ONE of: No (j)(i) It must have a degree of protection of IPX4. Is provided with a shield to prevent water spraying on it. Sprinkler heads are provided with suitable deflectors Sprinkler heads are of the dry type (j) Exception (g) 230 x 5% (1 mark) = 11.5V (1 mark) (h) (i) Any colour other than green, yellow, green/yellow, black or light blue Table 3.4 (ii) Green/yellow Table 3.4 (i) Any TWO of: Identified by an orange marker tape positioned above the cable. Marker signs where the cable enters or leaves the building Recorded on a plan that is located at the switchboard at which the cable originates. : (a) (b) (j) Any TWO of: Sockets outlet supplied at ELV have their voltage conspicuously marked Socket-outlets shall not accept plugs of other voltage systems. Socket-outlets shall not have a contact for a protective earthing conductor (a) FINAL-ER 42 ANSWERS 25 JUNE

5 Question 2 Marks Reference Marking notes (a) Any TWO of: Shall have a rating of not less than the full current Shall be capable of interrupting the locked-rotor or stall current of the motor Shall be capable of interrupting eight times the full load current (a) (i) (b) The isolating switch shall have a rating of not less that the control circuit current (b) (c) Where the motor is connected by a plug and socket. Where the motor is rated at not greater than 150 VA Exception (2)(i) and (iii) (d) Any TWO of: Motors associated with fire protection services in accordance with Clause Where the opening of the motor circuit could create a hazard. Shall not provided on a fire-pump motors where the operation of such devices might reduce the operating time of equipment under emergency conditions (e) To prevent the star and delta contactors closing simultaneously GK FINAL-ER 42 ANSWERS 25 JUNE

6 Question 3 Marks Reference Marking notes (a) I L = P (½ mark) 3 V L = (½ mark) 3 x 400 = 36.08A (1 mark) From Table 12, rating of 4mm 2 is 33A (½ mark) From Table 27(1) re-rating factor is 1.12 (½ mark) I max = 33 x 1.12 (½ mark) = 36.96A (1 mark) (b) Permitted voltage drop = 400 x 1.5% (1 mark) = 6 volts From Table 42, V d /A. (½ mark) = 9.71 for 4 mm 2 cable Vd = V d /A.m x I x L (½ mark) 1000 = 9.71 x x 20 (½ mark) 1000 = 7V (1 mark) (c) No. (½ mark) It does not meet the voltage drop (1½ marks) requirements. FINAL-ER 42 ANSWERS 25 JUNE

7 Question 4 Marks Reference Marking notes (a) (i) Any TWO of: Identification of the design Confirmation that the design complies with regulation 63 Identification of the supply system with which the installation is compatible. Signed by the designer of the installation. Compliance with ISO/IECV ESR 58(1) (ii) That the installation is installed in accordance with the design indentified in the declaration of conformity. (1 mark) ESR 57(2)(c) (b) (i) Verification of operation of residual current devices. (½ mark) GK Earth fault-loop impedance test (½ mark) GK (ii) Polarity tests (½ mark) GK Correct circuit connection tests (½ mark) GK (iii) Continuity of earthing (½ mark) GK Insulation resistance (½ mark) GK (iv) Mains work ESR 70(1)(c) (v) (1) The installation is electrically safe. (2) The installation complies with the Act and Regulations (1 mark) ESR 67(1)(a) (1 mark) ESR 67(1)(b) FINAL-ER 42 ANSWERS 25 JUNE

8 Question 5 Marks Reference Marking notes (a) (i) From : (½ mark) The minimum size of the main earthing conductor shall be determined from Table 5.1 in relation to the cross-sectional area of the largest active conductor of the consumers mains. (1½ marks) (ii) 10mm 2 (½ mark) : Table 5.1 (½ mark) (b) Any THREE of: Aerial conductors. Flat braided conductors. Busbars. Sheaths of MIMS cable. Conductive framework and wiring enclosures deemed to be an earthing conductor. Copper earthing conductors buried direct in the ground. Catenary wires. (3 marks) (c) No (½ mark) : Any ONE of: (1½ marks) * RCDs are not recognised as a sole means of basic protection against contact with live parts. * The use of such devices is not recognized as a sole means of protection and does not obviate the need to apply the protective measures specified in clause : : (d) Any ONE of: It shall not be used for the earthing of electrical equipment which is supplied from another switchboard : FINAL-ER 42 ANSWERS 25 JUNE

9 Question 5 Marks Reference Marking notes It shall not be used for the provision of earthing facilities for another distribution board. : FINAL-ER 42 ANSWERS 25 JUNE

10 Question 6 Marks Reference Marking notes (a) (i) (1) The socket outlet is located in a position that it is not likely to be accessed for general purposes. (2) The socket outlet is clearly marked to indicate the restricted purpose of the socket outlet and that RCD protection is not provided. (ii) Any TWO of: Install RCD at the switchboard at the origin of the final subcircuit. Install an SRCD on the bathroom socket outlet. Install an SRCD on a socket outlet upstream from the 1 st new socket outlet Exception 3(a) Exception 3(b) GK (b) It must be supplied by a dedicated circuit. It must be protected by an RCD with a maximum rated residual current of 10 ma The RCD must be positioned so that it may be reset by the patient while under treatment (3 marks) (c) (i) 30 milliamps. (1 mark) (ii) 10 milliamps (1 mark) (iii) 300 milliamps. (1 mark) FINAL-ER 42 ANSWERS 25 JUNE

11 Question 7 Marks Reference Marking notes (a) (i) Yes (½ mark) : Only the socket outlet for the connection of pool equipment is permitted. (½ mark) (b) Table 6.2 (ii) Supplied individually as a separated circuit in accordance with clause 7.4. Supplied by a residual-current device with a maximum rated residual current of 30 ma (b)(iii)(C) (b)(iii)(E) (iii) They must be designed and constructed specifically for use in a swimming pool. Have the required degree of protection Or Rated IPX8 Shall not be provided with a protective earthing conductor (a)(i) (a)(ii) (a) (b) Installed so as to prevent entry of moisture to any connection. Installed so as to prevent water siphoning system through any wiring enclosure or cable : (c) Any TWO of: Locate the electrical equipment at a distance from the pool with all plumbing connections being made of non-conductive materials. Insert metal grids or barriers in any plumbing connection between the electrical equipment and connected to the equipotential bonding system Use an RCD with a fixed rated residual current not exceeding 30 ma to protect circuits supplying Class I equipment. : (a) : (b) : (c) FINAL-ER 42 ANSWERS 25 JUNE

12 Question 8 Marks Reference Marking notes Equipment Load Group Calculation Load (A) W lighting points Group A(i) (30 x 100) 230 = 13 13A (1 mark) 10, 75W discharge lamps Group A(ii) (10 x 75) 230 = A (1½ marks) 18, 10A double socket outlets 10, 10A single socket outlets Group B = = 10A 20 = 5A 6 = 5A 20A (2½ marks) 6kW range electric Group C = x 0.5 = 13 13A (1½ marks) 6kW sauna Group D = x 0.75 = (1½ marks) 3KW heater water Group F = 13 13A (1 mark) Maximum demand 81.76A (1 mark) FINAL-ER 42 ANSWERS 25 JUNE

13 Question 9 Marks Reference Marking notes (a) (i) 200 mm Figure 4.7 (ii) 200 mm Figure 4.7 (iii) 200 mm Figure 4.7 (iv) 50 mm Figure 4.7 (b) (1) Not installed within 0.15 m of flammable materials or structural metalwork (2) Not installed within arms reach of the ground or any o0ther place a person is likely to stand. (c) Any TWO of: Installed immediately adjacent to an entrance to the room where the heater is located. Installed within the room where the heater is located. Installed on the switchboard where the room heater final subcircuit originates. (d) Clearly and permanently marking the functional switch or switches in the heated room area. Providing suitable labeling at the relevant switchboard (a) (b) : (a) (b) FINAL-ER 42 ANSWERS 25 JUNE