EKAS 2.8.1.1 Basic Electrical Principles

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EKAS 2.8.1.1Basic Electrical Principles
UEE31307 Certificate III in Refrigeration and
Air Conditioning Stage 2A Units UEENEEPOO1B,
UEENEEPOO2B Chris Hungerford Thursday, June 11,
2015
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Hazards Unsafe work practices

• Electric Shock
• Arcing
• Smoke

1. Unauthorized electrical work.
2. Inadequate work practices.
3. Live work.
4. Disregarding earthing circuits.
5. Untested test equipment.
6. Lack of tool maintenance.
7. Laziness fatigue.
8. Workplace fool.
9. Untested work before commencing work.
10. Untested work connected to a supply.
11. Disregard to Australian Standards.

2..8.1.1A
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Safety practices in the use of common tools and
plant

• Employees who are exposed to the hazards of
  falling, flying, abrasive and splashing objects,
  or exposed to harmful dusts, fumes, mists,
  vapors, or gases must be provided with personal
  protection equipment (PPE) necessary to protect
  them from the hazard.
• All hazards involved in the use of tools and
  plant can be prevented by following five basic
  safety rules
• Keep all tools and equipment in good condition
  with regular maintenance.
• Use the right tool for the job.
• Examine each tool and plant for damage before
  use.
• Operate according to the manufacturer's
  instructions.
• Provide and use the proper protective equipment.

2..8.1.1A
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Low voltage rescue
Accident
Rescuers safety
Rescue kit, Gloves crook Correct PPE
No
Yes
Isolate Supply
Free victim
Yes
Use fire blanket
Fire
No
Unsafe area
Use drag method
Yes
No
Send for help as soon as the situation allows
Clear area
Assess victims condition Resuscitate, treat
burns injuries
Await medical assistance
2..8.1.1.B
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Burns

• Management
• Remove casualty from danger, DRABC.
• Cool the burnt area, hold under cold running
  water for 10 min.
• Remove any constrictions, unless sticking to the
  burn.
• Cover burn.
• Calm casualty
• Call 000 for an ambulance.

• WARNING
• Do not apply lotions, ointment or fat to burn.
• Do not touch the injured area or burst any
  blisters.
• Do not remove any thing sticking to the burn.
• Keep a check for shock.

2..8.1.1.B
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Bleeding

• Management
• Apply pressure to the wound.
• Raise and support injured part.
• Bandage wound.
• Check circulation below wound.
• Treat for shock.
• Call 000 for an ambulance.

• WARNING
• Wear gloves to guard against infection.
• If casulalty becomes unconscious - DRABC.
• Do not apply a tourniquet.

2..8.1.1.B
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Shock

• Signs symptons
• weak, rapid pulse
• cold, clammy skin
• rapid breathing
• faintness/dizziness
• nausea
• pale face, fingernails, lips

• Management
• Lie casualty down, protect them from cold ground.
• Calm the casualty.
• Follow DRABC.
• Manage any injuries.
• Ensure comfort, if thirsty, moisten lips.
• Monitor breathing and pulse.
• Place in recovery position.
• Call 000 for an ambulance.

2..8.1.1.B
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DRABCD

• D danger
• R response
• A airway
• B breathing
• C circulation
• D defibrillator

2..8.1.1.B
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Danger

• to you
• to others
• to the casualty
• Make sure you dont become a second casualty

2..8.1.1.B
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Response

• - is the casualty conscious?
• gently shake the casualty and ask Can you hear
  me?, What is your name?
• if the casualty is conscious, check for and
  manage bleeding and other injuries.
• if the casualty is unconscious, they should be
  turned on the side

2..8.1.1.B
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Airway Australian Resuscitation Council
http//www.resus.org.au/ Guideline 4.

• Clear airway If foreign material is present in
  mouth, roll casualty on side and clear mouth with
  their fingers.
• Tilt head backward. Place one hand on the
  forehead and use the other hand to lift the chin.

2..8.1.1.B
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Breathing

• Look for the chest rising and falling
• Listen for the sound of breathing
• Breathing
• Yes - place casualty in side position
• No seal nose and give 2 breaths into mouth.

2..8.1.1.B
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Circulation

• feel the pulse at the neck (carotid pulse)
• No- commence CPR (cardiopulmonary
  resuscitation), 2 breaths 30 compressions at a
  rate of approximately 100/ minute.
• 5 cycles in 2 minutes
• Compress 1/3 depth of chest.
• Rescuers should minimize interruptions of chest
  CPR to check for signs of life.

2..8.1.1.B
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Defibrillator

• Minimise interruptions to chest compressions
• Give a single Defibrillator shock for ventricular
  fibrillation.
• If arrest is witnesses by a health care
  professional and a manual defibrillator is
  available, 3 shock may be given.
• After each defibrillation attempt give 2 minutes
  of CPR.

2..8.1.1.B
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The FIRE triangle

• Three components are required for a fire to
  exist fuel, heat, and oxygen
• Removing any one of these components the fire
  will not exist.
• To reduce the chance of fire in the workplace all
  three need to be kept separate.

Heat
Oxygen
Fuel
2..8.1.1.C
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2..8.1.1.C
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PCBs Polychlorinated biphenyl

• PCB,s congeners are odourless, tasteless, clear
  to pale-yellow, viscous liquids. They are formed
  by electrophilic chlorination of biphenyl with
  chlorine gas.
• They have high dielectric constants, very high
  thermal conductivity, high flash points (from 170
  to 380 C) and are chemically fairly inert, being
  extremely resistant to oxidation, reduction,
  addition, elimination, and electrophilic
  substitution.
• PCBs readily penetrate skin, PVC (polyvinyl
  chloride), and latex (natural rubber).
• PCBs are very stable compounds and do not degrade
  readily. Their destruction by chemical, thermal,
  and biochemical processes is extremely difficult,
  and presents the risk of generating extremely
  toxic dibenzodioxins and dibenzofurans through
  partial oxidation.
• PCBs were used as coolants and insulating fluids
  ('transformer oil') for transformers and
  capacitors especially in components of early
  fluorescent light fittings, electrical
  transformers, plasticizers in paints and cements,
  stabilizing additives in flexible PVC coatings of
  electrical wiring and electronic components,
  pesticide extenders, cutting oils, reactive flame
  retardants, lubricating oils, hydraulic fluids,
  sealants, adhesives, wood floor finishes,
  water-proofing compounds, casting agents, vacuum
  pump fluids, fixatives in microscopy, surgical
  implants, and in carbonless copy ("NCR") paper.
• Studies of workers indicate that PCBs were
  associated with specific kinds of cancer in
  humans, such as cancer of the liver and biliary
  tract. Polychlorinated biphenyls (PCBs) have been
  shown to mimic the action of oestrogen in breast
  cancer cells and can enhance breast
  carcinogenesis.
• PCB waste must be treated by a licensed/approved
  operator. Solid and liquid scheduled waste must
  not go to landfill. Quantities above 10kg must be
  notified to Department of Environment and
  Heritage.

2..8.1.1.C
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Simple Electric Circuit

• The basic electric circuit consists of the
  following three components.
• 1. a source
• 2. a complete path
• 3. a load to do work

2.8.1.1 D
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The Source

• a source of electrical pressure - battery to
  provide electrical energy for the system.
• other types of sources generators, alternators,
  solar cells, piezo crystals.

2.8.1.1 D
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The Source
The source is known as an EMF device. Electron
Motive Force. It places the electron in motion
by creating a pressure difference, therefore the
unit of an EMF is volts.
2.8.1.1 D
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Types of sources

• Electro-magnetic - alternators, generators.
• Photo-electric ----- solar cells.
• Thermo-electric --- thermocouples
• Piezo-electric ------ gas lighters, microphones
• Chemical ---------- cells and batteries
• Static ---------------- lightning.

2.8.1.1 D
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Component identification
Resistive components- all devices that have a
principle function of producing heat. Inductive
components- any device that has a coil and
principle operation uses magnetism. Capacitive
components- any device that stores an
electro-static charge.
2.8.1.1 D
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Resistance

• Resistance is the opposition to the flow of
  electrons.
• All materials exhibit a value of resistance to
  the flow of electrons. A good conductor has a
  small resistance, while an insulator has very
  high resistance.

• Resistance is a lot like friction they both act
  to oppose motion and generate heat.

2.8.1.1 D
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Component function
Impedance AC resistance
Reactance
Resistance
Urns
Irons
Inductance
Capacitance
Heaters
Toasters
Motors
Relays
Capacitors
Transformers
2.8.1.1 D
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Open Circuit

• An open circuit prevents current flow. A switch,
  fuse, or circuit breaker when operated will
  produce an open circuit.

??
An open switch
Open switch lamp is off.
2.8.1.1 E
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Closed Circuit

• A closed circuit allows current to flow. A switch
  can control both open and closed circuits.

??
Closed switch
Closed switch lamp is on
2.8.1.1 E
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Short Circuit
This type of circuit is to be avoided whenever
possible. The lamp is bypasses by a conductor
connected directly across the supply and reducing
the circuit resistance.
High current flow
Little current flow through the lamp, however
excessive current flows in the short. The
pressure of the circuit (volts) will also drop.
Little current
??
Short circuit
2.8.1.1 E
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Ohms Law

• The current flowing in a circuit is proportional
  to the voltage and inversely proportional to the
  resistance of the circuit.
• V Voltage
• I Current
• R Resistance

V
I
R
2.8.1.1 E
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Proportional to

• Proportional to , values that are directly
  opposite to each other in a formula is
  proportional to each other.

Hexagon is proportional to the square.

Star is proportional to the circle.
2.8.1.1 E
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Inversely proportional to

• Inversely proportional to, values that are
  diagonal to each other are inversely proportional
  to each other.
• This technique applies to all formularies.

The star is inversely proportional to the square.

The hexagon is inversely proportional to the
circle.
2.8.1.1 E
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Triangle thumb

• To transpose the formula, draw the triangle as
  shown.
• Voltage ?
• Move thumb over voltage and the remainder equals
  the voltage.

V
I
R
2.8.1.1 E
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Triangle thumb

• Voltage current X resistance
• Determine the resistance.

V
I
R
2.8.1.1 E
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Triangle thumb

• Thumb over the resistance.
• Resistance the remainder.
• Resistance voltage/current

V
I
R
2.8.1.1 E
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Transposing formula

• Current voltage / resistance
• Resistance voltage / current
• Voltage current X resistance

I V R
R V I
VI R
2.8.1.1 E
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Applying Ohms Law

• Determine the current flow.

I?
V
10v
5?
I
R
I V 10 2A R 5
2.8.1.1 F
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Applying Ohms Law
Determine the Resistance.

I5A
V
100v
R?
I
R
R V 100 20? I 5
2.8.1.1 F
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Applying Ohms Law
Determine the Voltage.
I12A

V
V?
20?
I
R
VI R 12 x 20 240v
2.8.1.1 F
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Problem Solving
Voltage Current Resistance
I
50v
5A
R
V
16?
240v
12?
1A
Calculate the missing value using ohms law.
2.8.1.1 F
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Summary

• Ohms law is the relationship between voltage,
  current, and resistance.

50v
5A
10?
16?
240v
15A
12?
1A
12v
2.8.1.1 F
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Problems

• Determine the resistance of a 240v heating
  element that has a current of 20amps.
• A 240v light bulb, has a measured resistance of
  960?, determine the circuit current.
• A 240v element of 48? has been replaced by a 240v
  element with a resistance of 16?. If the circuit
  is protected by an 8A circuit breaker, determine
  the effects on the circuit.

2.8.1.1 F
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AS/NZS-30002007, Wiring Rules
3.7 ELECTRICAL CONNECTIONS 3.7.1
General Connections between conductors and
between conductors and other electrical equipment
shall provide electrical continuity and adequate
mechanical strength.
2..8.1.1.G
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Solderless lugs

• Ross - Courtney lug.
• Stanco lug

2..8.1.1.G
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Crimps

• Terminating - crimp lugs.
• Joining cables of the same size - crimp links.
• When crimping it is important that the correct
  crimp type lug for the cable and the correct tool
  for that lug is used.
• AS/NSZ 3000 cl 3.7.2.3.2

2..8.1.1.G
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Terminal connections

• AS/NZS 3000 cl 3.7.2.4
• Blue point connectors (BP)
• Line taps.
• Articles terminals.
• Terminal strips.
• Bolted clamp connectors,

2..8.1.1.G
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AS/NZS-30002007 Wiring Rules
3.7.2.7 Soldered connections Where a soldered
connection is used the design shall take account
of creep, mechanical stress and temperature rise
under fault conditions.
2..8.1.1.G
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Stripping of Insulation.

• Avoid using a knife on smaller cables.
• Tear the insulation off, dont cut.
• Do not indent any conductor material.
• Be sure not to remove excessive insulation.
• Remake any damaged insulation.
• The only connection for an extension lead is via
  an approved plugtop and socket.

2..8.1.1.G
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AS/NZS-30002007 Wiring Rules
3.7.2.2 Preparation for connection The insulation
on a conductor shall not be removed any further
than is necessary to make the connection. For
connections between insulated conductors the
connection shall be insulated to provide a degree
of insulation not inferior to that of the
conductors. Any damaged insulation shall be
reinstated.
2..8.1.1.G
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Terminations and connections

• Connections must not be soft soldered before
  compression terminations.
• Must be seated correctly.
• Free of dirt and oxides.
• Use a suitable lug or connector.
• Insulated to the equivalent of the original
  insulation.
• Earth connection must be painted if exposed to
  weather

2..8.1.1.G
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AS/NZS-30002007 Wiring Rules
3.7.2.6 Mechanical stress All cables and
conductors shall be installed so that there is no
undue mechanical stress on any connection.
2..8.1.1.G
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AS/NZS-30002007 Wiring Rules
3.7.2.3.1 Loosening of connections Connections
shall be made so that no loosening is likely
because of vibration, alteration of materials or
temperature variations to which the
connections are likely to be subjected in normal
service.
2..8.1.1.G
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Further reading Workbook Risk management
Questions Workbook, Topic 3, Q1 Q90