7. Theory

• 7.1. Basic knowledge and understanding of electrical circuits
• 7.2. Electricity supply
• 7.3. Electrical terms
• 7.4. Electrical safety of personnel
• 7.5. Dangers of electric shock
• 7.6. Basic first aid
• 7.7. Cardiopulmonary resuscitation
• 7.8. Protection devices
• 7.9. Circuit protection
• 7.10. Radio and television interference suppression
• 7.11. Electrical conductors
• 7.12. Electrical insulators
• 7.13. Flexible cords
• 7.14. Electrical fittings
• 7.15. Electrical appliances
• 7.16. Electrical measuring instruments
• 7.17. Electrical appliance testing
• 7.18. Electricity Regulations, Standards and Codes
• 7.19. Limits of work and other responsibilities of "A" level registration holders

7.1. Basic knowledge and understanding of electrical circuits

1. General
   
   Describe the elements of an electric circuit, i.e.:
   • Source (battery, generator, a.c. mains, etc.).
   • Conductors (positive, negative, phase, neutral, earth).
   • Insulation (to contain the conductors within defined limits)
   • Control (switches, thermostats, energy regulators, etc.).
   • Protection (fuses, circuit breakers, etc.).
   • Metering (voltmeter, ammeter, watt-hour meter, etc.).
   • Load (current using devices). [Attainment level: B]
      
2. Ohms law
    
   1. Understand the relationship existing between current, voltage, and resistance in terms of Ohm's law. [Attainment level: A]
   2. State the formula I=V/R. [Attainment level: A]
   3. Transpose the formula and perform simple calculations to obtain an unknown value. [Attainment level: A]
   4. Understand voltage drop may also be calculated using Ohm's law.
      [Attainment level: A]
       
3. Electrical circuits
    
   1. Describe a series circuit. [Attainment level: B]
   2. State the characteristics of a series circuit. [Attainment level: B]
   3. Draw and label series circuit diagrams incorporating commonly used components. [Attainment level: B]
   4. Recognise and use the correct standard symbols for circuit components. [Attainment level: C]
   5. Describe a parallel circuit. [Attainment level: B]
   6. State the characteristics of a parallel circuit. [Attainment level: B]
   7. Draw and label diagrams of simple parallel and series-parallel circuits incorporating commonly used components.
      [Attainment level: B]
   8. Indicate on the diagrams the correct connections for the voltmeter, ammeter and ohmmeter. [Attainment level: B]
   9. Explain why electrical appliances are normally parallel connected rather than series connected. [Attainment level: C]
   10. Describe the essential differences between a.c. and d.c. current.
       [Attainment level: C]
        
4. Power and energy
    
   1. Understand the relationship between voltage, current and power.
      [Attainment level: A]
   2. State the units in which power is measured. [Attainment level: A]
   3. State the formulae P=V2/R, P=I2R, P=VxI. [Attainment level: B]
   4. Transpose the formulae and perform simple calculations to obtain an unknown value. [Attainment level: B]
   5. Understand the relationship between voltage, current, time and energy. [Attainment level: A]
   6. State the units in which energy is measured. [Attainment level: A]
   7. Convert horsepower to watts and vice versa. [Attainment level: B]

7.2. Electricity supply

Explain the principal purpose of the MEN system ie:

• ensures high fault current flow, and
• results in rapid and positive operation of the circuit protection devices.
  [Attainment level: B]

7.3. Electrical terms

1. Have an understanding of electrical terms, symbols and values including formulae and calculations invoking V, I, R, W and V drop.
   [Attainment level: A]
    
2. Understand and explain the following terms:
   • Voltage (Volt).
   • Electromotive force.
   • Potential difference.
   • Voltage drop.
   • Current flow (Ampere).
   • Resistance (Ohm).
   • Power (Watt).
   • Energy (Watt-hour).
   • Insulation resistance.
   • Continuity.
   • neutral conductor
   • earth continuity conductor.
   • phase conductor (Active, Line conductor).
   • earthing lead.
   • Short circuit (between conductors and to earth).
   • Open circuit.
   • Low Voltage.
   • Extra Low Voltage earth.
   • earthed situation.
   • Exposed metalwork.
   • earthed metal.
   • earth free situation.
   • Closed circuit.
   • Electrical fault.
   • Efficiency.
   • kVA.
   • pF.
     
     Convert between the multiples and sub-multiples of
     the above where applicable. [Attainment level: B]
      
3. Understand the terms:
   • RMS Value.
   • Frequency.
   • Cycle.
   • Maximum or peak value.
   • Sine wave.
     [Attainment level: C]

7.4. Electrical safety of personnel

1. State the factors that contribute to safety in the workplace, e.g.:
   • the wearing of suitable clothing for the job.
   • ensuring working conditions are safe.
   • safe use of ladders and lifting gear.
   • safety relating to noxious materials, acids, gasses, fumes,
     dust, etc.
   • the correct use of machine tools.
   • the promotion of good workshop behaviour.
     [Attainment level: A]
      
2. Explain the purpose and uses of (including diagrams):
   • the isolating transformer.
   • double insulation.
   • residual current devices (RCDs).
     [Attainment level: A]
      
3. Understand the danger represented by exposed live parts and conductors with respect to:
   • components or conductors operating at different potentials.
   • earth potential.
   • connecting any electrical appliance or apparatus that may become an electrical hazard.
   • the need to suitably label any such electrical appliance and remove it from the work area if possible.
   • the need to ensure that all covers, screens and guards provided with portable electrical appliances are in good order and are firmly fixed in their correct positions at the completion of any work carried out on the appliance.
   • the need to always test work before connecting it to the supply.
     [Attainment level: A]
      
4. State, which types of fire extinguisher, must or must not be used on an electrical fire. [Attainment level: A]
    
5. Understand that the power supply to the burning equipment must be turned "off" before attempting to extinguish the fire.
   [Attainment level: A]
    
6. Nominate appropriate procedures that will assist in preventing contact with live components, e.g. disconnect from the supply before working on electrical equipment. [Attainment level: A]
    
7. State why it is usually necessary to earth the exposed metalwork of electrical appliances, e.g., electric shock hazard or fire risk.
   [Attainment level: A]
    
8. Explain how a portable metal clad electrical appliance is connected to earth and why it is necessary to ensure the lowest possible resistance in this circuit. [Attainment level: A]
    
9. Understand the need for clean, tight earthing connections with no cut or loose strands of flexible conductor. [Attainment level: A]
    
10. Understand that earth continuity is expressed in terms of conductor resistance and that this must not exceed the values stated in AS/NZS 3760. [Attainment level: B]
     
11. Understand that as the earth continuity conductor's resistance increases it will adversely effect the operating time of the protective device.
    [Attainment level: A]
     
12. Explain why all single pole switches must be connected in the phase conductor of electrical appliance wiring. [Attainment level: A]
     
13. Describe suitable means of preventing further use of a defective or hazardous electrical appliance, including the use of appropriate "tie on" notices. [Attainment level: C]
     
14. Understand the precautions necessary when handling or working with capacitors that may retain a charge. [Attainment level: B]
     
15. Understand the precautions necessary when working in hazardous locations and/or environments, and in damp situations.
    [Attainment level: A]
     
16. Understand the various "conditions of use" and "types of safeguard" approved for use with electrical appliances. [Attainment level: B]

7.5. Dangers of electric shock

1. State why peak voltages are important in respect to electric shock and insulation resistance. [Attainment level: A]
    
2. Understand the danger of being in contact with phase and neutral or phase and earth conductors simultaneously. [Attainment level: A]
    
3. Understand the effects that various values of voltages, current, contact duration or other conditions (wet skin, etc.) will have on the victim of an electric shock. [Attainment level: A]

7.6. Basic first aid

1. General
   
   Procedures outlined in this section are intended only to give a general knowledge of safe, effective methods of applying first aid for certain types of injuries. Good first aid training is important in developing safe workers.
    
2. Objective
   
   The main aim of first aid is to provide the patient with treatment as soon after the accident as possible in order to:
   • sustain life,
   • prevent the condition from becoming worse, and then obtain professional assistance.
      
3. Basic rules
    
   1. Do all you can to attract assistance.
   2. Tell helpers clearly what you want them to do.
   3. Warn bystanders of any possible hazards.
   4. Never move a patient unless he/she is in immediate danger - you could make the injuries worse.
   5. Do all you can to reassure the patient.
       
4. General procedure
   
   The survival of a patient may depend upon the first aider's attention to certain priorities. These must be dealt with in the following order:
   • establish clear airway.
   • determine the level of consciousness.
   • control external bleeding.
      
5. Suffocation or gassing
    
   • remove the patient to fresh air.
   • apply artificial respiration if necessary.
   • treat for shock and keep any severe case lying down until he/she is seen by a doctor.
      
6. Loss of consciousness
   
   Loss of consciousness from a blow on the head or from a fall may be serious.
   • place the patient in the recovery position unless he/she has neck or spinal injuries.
   • treat for shock and consult a doctor even if consciousness is very quickly regained.
      
7. Minor cuts and scratches 
   
   Wash as clean as possible then swab with an antiseptic liquid. When dry, apply a sterile dressing, or cover with a small adhesive dressing impregnated with antiseptic.
    
8. Severe bleeding
    
   • apply direct pressure with the fingers to the bleeding point or points using a dressing if available.
   • if the wound area is large, press the sides of the wound firmly but gently together.
   • elevate the wounded part if possible, except in the case of a fracture.
   • if the bleeding is not quickly controlled by a properly applied dressing, put on more pressure by adding a second larger dressing over the top and bandaging more firmly, or by pressing on the dressing with the palm of the hand.
   • do not remove the dressing. avoid disturbing any clots of blood.
   • treat for shock and arrange medical attention.
      
9. Foreign body protruding from the wound
   
   If a foreign body is protruding from the wound:
   • DON'T remove it.
   • DON'T press down on it.
   • cover the wound with a sterile dressing and mould a ring pad to fit around it so that the bandage doesn't press the object further in, then bandage firmly.
   • in the meantime, press firmly but gently from the sides of the wound with the flat part of the fingertips.
   • the patient must be put in the recovery position unless he/she has neck or spinal injuries.
   • treat for shock and arrange medical assistance.
      
10. Bleeding or fluid from the ear
    
    This may mean that the patient's skull is fractured.
    • place a dressing or pad over the ear and bandage tightly.
    • if the patient is conscious, and provided he/she does not have neck or spinal injuries, place him/her in a half sitting position with the head leaning towards the injured side so that the blood or fluid can drain.
    • treat for shock and arrange medical attention.
    • if the patient is unconscious and provided he/she does not have neck or spinal injuries, place him/her in the recovery position with the injured ear downward.
    • watch his/her breathing and pulse rate.
    • get him/her to hospital urgently.
       
11. Shock
    
    Shock accompanies most injuries. The patient is pale and sweats profusely, he/she feels faint and sick and his skin is cold and clammy. His pulse becomes weak.
    • reassure the patient, loosen any tight clothing and lay him/her on his back with his head low and turned to one side.
    • wrap him/her in a blanket for warmth but do not overhead.
    • provided it will not interfere with any injuries, raise his legs to increase the supply of blood to the brain.
       
12. Serious shock
    
    If the patient loses consciousness and cannot be revived, his condition is serious and needs urgent hospital treatment. Make sure that he/she continues to breathe and control bleeding if necessary.
     
13. Electric shock
    
    It is essential to free the patient from any electrical contact with electrical sources before attempting any form of treatment.
    If the supply cannot be promptly switched off, free the patient from electrical contact by use of a dry stick, rope, clothing or other non-conducting material. Bare hands must not be used in direct contact with the patient unless you are insulated from ground by non-conducting material.
     
14. Eye injuries
    
    If a foreign body cannot be removed from the eye by irrigation of the eye with water, and provided the foreign body is not on the pupil or embedded in the eye, try to remove with the corner of a handkerchief.
    Do not attempt to remove the foreign body if it is:
    • on the pupil of the eye.
    • in, or sticking to, the eyeball.
    • cannot be seen, but the eye is inflamed and painful.
    • chemical splash in the eye, whether acid or alkaline, must be washed out immediately with plenty of water for several minutes. prompt application of water is essential.
    • in all cases involving foreign bodies or chemical splashes to the eye, get the patient to a doctor as soon as possible.
       
15. Fractures
     
    1. Under normal circumstances it is preferable to await the arrival of qualified ambulance personnel, particularly when a spinal injury is suspected.
       Fractures may be classed as:
       • closed fractures, i.e. the skin is not broken.
       • open fractures, i.e. there is a wound over the fracture.
    2. General treatment of a closed fracture:
       Methods of treatment vary according to the bones broken. In general, the treatment consists of making the patient comfortable, immobilising the fracture by strapping or tying the affected part to a sound part of the body. For example, an arm against the side, or a leg to a leg, or splinting the broken bone as well as possible with materials to hand.
    3. General treatment of an open fracture:
       The open fracture is a much more dangerous injury than a closed fracture. Because of the open wound there is a possibility of infection.
       It is important to apply a sterile dressing or clean pad over the wound at once. This seals the wound, which is then given the same treatment as a closed fracture.
        
16. Sprains
    
    To ease pain and control swelling, apply a firm bandage and cold packs or water. Re-apply the treatment when it ceases to give relief.
     
17. Burns and scalds
    • the immediate treatment is cold water. place the affected part in cold water or gently running water from a tap for at least ten minutes. then cover the burn area with a sterile dressing or cloth.
    • severe burns can result in fluid loss, so give the patient cold drinks at frequent intervals. This will replace the fluids and lessen shock.
    • do not remove burnt clothing.
    • do not apply ointments or lotions.
    • do not prick blisters, breathe on, cough over, or touch the area as this increases the risk of infection.
    • burns from corrosive liquids must be washed freely with water before dressing.
    • treat for shock and arrange medical attention.

7.7. Cardiopulmonary resuscitation

Guidelines for CPR are issued by the New Zealand Resuscitation Council and are available from their website www.nzrc.org.nz.
(Click on "Courses" then "How to do CPR". Downloads for resuscitation of Adults, Children and Infants are available.)

7.8. Protection devices

1. Describe the basic operating principle of a residual current device (RCD). [Attainment level: A]
    
2. Explain why the residual current device must be operationally tested regularly. [Attainment level: B]
    
3. Understand that the residual current device may permit a current to pass from phase to earth through a person's body (in certain circumstances) and that the time duration is such that personal harm is avoided.
   [Attainment level: D]
    
4. Understand that RCDs provide supplementary protection the users of electrical appliances and equipment [Attainment level: A]
    
5. Know the maximum tripping current and operating times [NZS 3019].
   [Attainment level: A]
    
6. Understand the operational characteristics of RCDs and how different types of the available RCDs operate including:
   • RCDs functionally independent of line voltage (used in residential type switchboards and SRCDs)
   • RCDs functionally dependent on line or auxiliary voltage (used in PRCDs)
      
7. Describe the basic operating principle of an isolating transformer.
    
8. Explain why the isolating transformer provides maximum safety when used with only one electrical appliance connected. [Attainment level: C]
    
9. Explain why it is necessary, when two or more electrical appliances are connected simultaneously to one isolating transformer, their earth continuity conductors are connected together at the transformer but must not be earthed. [Attainment level: B]
    
10. Understand that the isolating transformer may be used in conjunction with other approved safeguards for extra protection where considered desirable. [Attainment level: C]
     
11. Understand the various "conditions of use" and "types of safeguard" approved for use with electrical appliances. [Attainment level: B]

7.9. Circuit protection

1. Explain what "excess current protection" is and how it reduces:
   • Electric shock hazard.
   • Overheating and fire. [Attainment level: B]
      
2. Describe the principle of operation and advantages and disadvantages of:
   • rewirable fuses.
   • HRC fuses.
   • circuit breakers.
   • glass cartridge fuses. [Attainment level: B]
      
3. State typical applications for the protective devices listed above.
   [Attainment level: B]
    
4. Understand and state the meaning of the following terms:
   • rated current.
   • fusing current.
   • utilisation category (which replaced fusing factor.)
   • rupturing capacity.
   • close excess current protection.
   • coarse excess current protection. [Attainment level: A]
      
5. Describe the steps required to:
   • identify a "blown" fuse.
   • isolate the fuse base from both supply and load.
   • rewire the fuse carrier or replace the cartridge.
   • replace the fuse carrier in its fuse base.
     [Attainment level: A]
      
6. State the reasons for using the tortuous path provided by the manufacturer when rewiring a rewirable fuse. [Attainment level: A]
    
7. Understand the danger of leaving ends of fuse wire exposed to touch outside the fuse carrier of a rewirable fuse. [Attainment level: A]
    
8. State why a "blown" HRC fuse must not be repaired or replaced with fuse wire, e.g.:
   • danger of arcing if blown again.
   • fusing factor may no longer be appropriate. [Attainment level: A]
      
9. Understand the current rating of tinned copper wire of various diameters used for rewiring fuses. [Attainment level: B]
    
10. Understand the need to replace fuse cartridges with items of the same type or comparable type and rating as the "blown" cartridge, and to explain why this is necessary. HRC fuse labelling in accordance with Standards BS88:1998 and IEC 20269 or AS/NZS 20269. 
    [Attainment level: B]
     
11. Describe the types and purpose of "internal" protection devices commonly used within electrical appliances, e.g.
    • fuses (including miniature glass cartridge type).
    • fusible links.
    • overload relays (magnetic and thermal). [Attainment level: C]
       
12. Understand that fuses, overloads and fusible links to be of the correct rating and in correct working order. [Attainment level: A]

7.10. Radio and television interference suppression

1. Identify the principal components used, i.e.:
   • The capacitor.
   • The inductor (choke). [Attainment level: C]
      
2. Explain why the total capacitance connected to the exposed metalwork of any electrical appliance must not exceed 0.005 microfarad.
   [Attainment level: A]
    
3. Explain why interference suppression devices must not be connected in the earth continuity conductor of any electrical appliance.
   [Attainment level: A]
    
4. Understand why replacement suppression capacitors for use with 230 volt electrical appliances must be rated for voltage considerably in excess of 230 volts. [Attainment level: B]

7.11. Electrical conductors

1. Describe the properties of commonly used conductors for:
   • use in flexible cord or flexible cable.
   • rigid use, e.g.:
   • contacts.
   • terminals.
   • heating elements.
   • lamp filaments. [Attainment level: C]
      
2. Compare the practical advantages and disadvantages of commonly used conductors when exposed to heat, moisture, corrosive materials, dust, gases, tension, compression and vibration, e.g.:
   • copper.
   • silver.
   • aluminium.
   • tungsten.
   • carbon.
   • nichrome.
   • brass.
   • bi-metals. [Attainment level: C]
      
3. Understand the importance of secure, well made connections in prolonging the service life of a conductor. [Attainment level: B]
    
4. Identify suitable conductors for various practical applications.
   [Attainment level: B]

7.12. Electrical insulators

1. State the purpose for which insulating materials are used, e.g.:
   • protection against accidental personnel contact with live conductors.
   • protection against short circuiting between conductors.
   • protection against leakage to earth. [Attainment level: B]
      
2. Describe the properties of an ideal conductor for:
   • use on a flexible cord conductor or as a sheathing.
   • rigid use, e.g.:
   • supports for electrical elements.
   • framework for portable electrical appliances.
   • separation barriers between live and earthed components.
     [Attainment level: C]
      
3. Compare the practical advantages and disadvantages of commonly used insulators when exposed to heat, moisture, corrosive materials, dusts, gases, tension, compression and vibration, e.g.:
   • glass.
   • mica.
   • oils.
   • ceramics.
   • rubber.
   • plastics (various). [Attainment level: C]
      
4. State the importance of "insulation resistance" as an indicator of an insulator's condition. [Attainment level: A]
    
5. Identify suitable insulators for various practical purposes.
   [Attainment level: B]

7.13. Flexible cords

1. Describe commonly used types of flexible cord and list typical applications for each, e.g.:
   • twin and three core.
   • twisted, parallel and circular construction.
   • TRS and TPS sheathing.
   • PCP, HO-FR and PVC sheathings for oil and petrol contact.
     [Attainment level: B]
      
2. State the types of sheathings used for high temperatures and give typical applications for each. [Attainment level: B]
    
3. State the New Zealand approved distinguishing colours by which each core in a flexible cord may be identified. [Attainment level: A]
    
4. Explain the effects of conductor length, cross sectional area and ambient temperature on the current carrying capacity of flexible cords.
   [Attainment level: B]
    
5. Discuss the effects of oils, petrol, excessive weight or strain, and extremes of temperature on the insulation and sheathing of commonly used flexible cords. [Attainment level: B]
    
6. Understand that the selection of a flexible cord for use with an electrical appliance may be dependent upon the temperature or other conditions prevailing at the point of entry and connection within the electrical appliance. [Attainment level: B]
    
7. Understand the use of tables relating to current ratings, voltage drop and temperature rating factors for various sizes and types of flexible cord.
   [Attainment level: B]

7.14. Electrical fittings

1. Define the term "electrical fitting" and list examples of those used with electrical appliances and flexible cords. Identify light or heavy-duty electrical fittings where applicable. [Attainment level: C]
    
2. Describe the step by step procedure for connecting flexible cords to plugs, cord extension sockets, appliance connectors, lampholders and adaptors (bayonet cap and Edison screw types). [Attainment level: A]
    
3. List the reasons why the use of lampholder adaptors to connect electrical appliances to the electrical supply are illegal, e.g.:
   • no guarantee of polarity (bayonet type).
   • no earthing facility.
   • current limitations (bayonet and Edison screw types).
     [Attainment level: C]
      
4. State the reason why the earthing pin on the three-pin plug is longer than the phase and neutral pins. [Attainment level: B]
    
5. State the reason why it is recommended that, when connecting a flexible cord to an electrical appliance or accessory, the earth continuity conductor should be made longer than the associated phase and neutral conductors. [Attainment level: B]
    
6. Correctly identify the pin polarity of three pin accessories, Edison screw lampholders, and the earthing facility on electrical appliance connectors.
   [Attainment level: A]
    
7. Discuss the importance of replacing internal wiring of portable electrical appliances, when required, with similar or equivalent alternative conductors by considering:
   • current carrying capacity.
   • quality of insulation to suit the electrical appliance operating voltage.
   • operating temperature.
   • need for flexibility or rigidity as required. [Attainment level: A]
      
8. Recognise the limitations that may apply to the use of electrical fittings, e.g.:
   • current limits.
   • voltage limits.
   • environmental restrictions. [Attainment level: B]
      
9. Discuss the techniques of sleeving or whipping fabric covered flexible cords, and the need for accurate, tidy work when fitting these cords to electrical fittings. [Attainment level: B]
    
10. Understand why some a.c. switches are not suitable for d.c. applications.
    [Attainment level: B]
     
11. Understand the operating principles and typical uses of the following types of control devices:
    • energy regulator (simmerstat).
    • thermostats of various types.
    • pressure switch.
    • limit switch.
    • time switch.
    • single and double pole switches.
    • single and double throw (centre "off") switches.
    • two way control switching.
    • three heat switching (for two section resistive load).

This list is not exhaustive. [Attainment level: D]

7.15. Electrical appliances

1. Define the term "electrical appliance" and describe the difference between earthed and double insulated electrical appliances.
   Explain how each provides safety from electric shock.
   [Attainment level: B]
    
2. Briefly describe the general operating principles of the following types of electrical appliances:
   • heating appliance.
   • cooking appliance.
   • appliance incorporating electric motors.
     [Attainment level: C]
      
3. Explain why the metal lamp guards of inspection hand lamps and the exposed metalwork of double insulated electrical appliances must not be deliberately connected to earth. [Attainment level: B]
    
4. Draw the internationally recognised symbol for a double insulated electrical appliance. [Attainment level: C]
    
5. Have knowledge and understanding of single phase electric motors, connections and reversal of rotation. [Attainment level: B]
    
6. Have knowledge of single phase motor starters and their control circuitry.
   [Attainment level: B]

7.16. Electrical measuring instruments

1. Identify the correct instrument to measure:
   • voltage.
   • current.
   • resistance.
   • insulation resistance.
   • earth continuity.
   • power. [Attainment level: B]
      
2. Describe the correct method of connecting indicating instruments in a circuit to obtain meaningful results, e.g.:
   • connect a voltmeter across the circuit or component.
   • connect an ammeter in series with the circuit or component.
   • connect an insulation resistance tester between open circuited conductors and from each conductor and earth.
   • connect an ohmmeter to form a closed series circuit with its associated power source, zeroing resistance and the resistance to be measured. [Attainment level: B]
      
3. Understand that an ohmmeter, if of the analogue type, must be calibrated (zeroed) with its power source before use. Explain how this is carried out and why it is necessary. [Attainment level: C]
    
4. List the usual functions available in a multimeter and understand the relationship existing between different ranges of the same function.
   [Attainment level: C]
    
5. State the likely results of using test instruments connected in circuit incorrectly or, where a multimeter is used, switched to incorrect functions or inappropriate ranges. [Attainment level: B]
    
6. Ensure correct instrument polarity when working with moving coil analogue type meters on direct current circuits. [Attainment level: B]

7.17. Electrical appliance testing

1. Identify the appropriate instrument for testing an electrical appliance for:
   • circuit continuity (open or short circuits, dry or loose connections).
   • insulation resistance (to earth and between phase and neutral).
   • polarity (phase-neutral and phase-earth reversal).
   • earth continuity (open circuits, dry, loose or corroded connections)
   • effectiveness of controls and safety facilities.
     [Attainment level: B]
      
2. Describe methods of carrying out tests listed above and state minimum and maximum results (where appropriate) that are considered satisfactory. [Attainment level: A]
    
3. Understand the reasons for each of the tests listed above.
   [Attainment level: B]
    
4. List the limitations of the multi-meter and insulation resistance tester when used for testing insulation resistance and earth continuity.
   [Attainment level: C]
    
5. Explain why it is necessary to carry out insulation resistance tests at twice the normal applied voltage. [Attainment level: B]
    
6. Describe the various conditions, indications and defects that can be found by visual examination of an electrical appliance being checked for compliance with regulation requirements and for general electrical and mechanical safety. [Attainment level: A]
    
7. Describe operating precautions that must be observed when connecting a test instrument into a circuit, e.g.:
   • use the correct instrument (or function if using a multi-meter).
   • observe correct polarities where necessary.
   • use the range appropriate for the expected result.
   • check that connections are clean, tight and safe.
     [Attainment level: B]
      
8. Understand the necessary safety procedures when using instruments to test "live" circuits, e.g.:
   • do not energise the circuit until appropriate instrument connections have been completed.
   • maintain adequate insulation and clearances between instrument clips, probes or leads.
   • avoid personal contact with either live conductors or earth when using instruments on live circuits.
     [Attainment level: A]

7.18. Electricity Regulations, Standards and Codes

7.19. Limits of work and other responsibilities of "A" level registration holders

1. State the extent to which electrical work may be carried out:
   • After passing the Electrical Service Technicians "A" examination.
   • After obtaining registration from the Electrical Workers Registration Board. [Attainment level: A]
      
2. Understand that the Board may impose certain limits or restrictions on the work that may be undertaken or where or for whom the registered person may work. [Attainment level: A]
    
3. Understand and explain the terms "Supervision" and "Supervisor of electrical work". [Attainment level: A]
    
4. Describe the responsibilities binding upon persons carrying out prescribed electrical work including:
   • The need to ensure compliance with the Electricity Act 1992, Electricity Regulations 1997, Standards and Codes and other legal requirements insofar as they apply to the work undertaken.
   • The need to ensure a high standard of workmanship.
   • The need to work safely.
   • The limits and restrictions that apply to persons who may assist a registered Electrical Service Technician in carrying out prescribed electrical work.
     [Attainment level: A]
      
5. State the importance of engaging a Registered Electrician to carry out any electrical work beyond that for which the Electrical Service Technician registration has been issued, or in those instances where doubt about the work exists. [Attainment level: A]

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