ELECTRICAL INSTALLATION PLANNING

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ELECTRICAL INSTALLATION PLANNING

• LSEGG307A
• 9080F

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Assessments
Theory Test 1 Theory Test 2 Assignments Final
Examination
10 20 10 60
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Lesson Content

• Protection against harmful effects
• Correct functioning
• Supply characteristics
• Determining Maximum demand
• Voltage drop limitations
• Arrangement into circuits
• External Factors
• Protection against
• Integrity of fire rated construction

• Direct contact
• Indirect contact
• Thermal effects
• Overcurrent
• Faults
• Mechanical movement

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SELECTION OFCABLE EQUIPMENTWITH REGARD TO

• Type of structure/location what it is used for
• Number type of circuits
• Current carrying capacity of the cable
• Voltage drop
• Fault loop impedance
• Maximum demand
• Fault levels
• Metering
• Damp situations
• Voltage levels

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What you will require each week

• AS/NZS 30002007
• AS/NZS 3008 1998
• Calculator

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THIS SUBJECT WILL BE EXAMINED IN THE CAPSTONE TEST
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Lesson 1
Determining a Wiring System for an Installation
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What determines the type of building structure
chosen?

• How it is going to be used
• Local authority requirements
• Cost
• Time requirements
• Site access
• Appearance/Aesthetics

• Domestic
• Multiple domestic
• Commercial
• Industrial

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What Determines The Type of Cable System Chosen?

• Power requirements of each of the loads connected
• How the loads are used
• Flexibility
• Safety of Human Property and Livestock
• Not be too inconvenient if a fault occurs
• Be able to be easily worked on and tested
• Compatible with the climate
• Not be overloaded
• Not have too much voltage drop
• Not be affected by the Environment/Atmosphere

Constant or Intermittent
Temperature, High Humidity, Corrosive
atmospheres, Mechanical damage, etc
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What Determines The Type of Cable System Chosen?

• Power requirements of each of the loads connected
• How the loads are used
• Flexibility
• Safety of Human Property and Livestock
• Not be too inconvenient if a fault occurs
• Be able to be easily worked on and tested
• Compatible with the climate
• Not be overloaded
• Not have too much voltage drop
• Not be affected by the Environment/Atmosphere

Temperature, High Humidity, Corrosive
atmospheres, Mechanical damage, etc
AS/NZS 3000 1.6.1
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Other Factors That An Electrician Has To
Consider/Abide by -

• AS/NZS 3000 and other electrical standards
• Local supply authority standards
• Building codes
• Fire ratings
• Heritage orders etc
• Appearance
• Speed of installation
• Cost

Concealed or Surface
Materials Labor
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Timber Frame
Advantages

• Insulator, so earthing not a problem
• Material relatively soft so cable damage not a
  major problem

Disadvantages

• Drilling in structural members is limited
• All service holes have to be drilled on site

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Steel Frame
Used extensively used in office partitions
Advantages

• Most service holes are pre punched and
  de-burred/flanged
• Very lightweight construction.

Disadvantages

• Earthing of the frame has to be considered
• Additional holes made must be de-burred

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Timber Steel Frame
TPS inside frame is most commonly used
Why?
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Full Brick Concrete Slab
Concrete slab Deck work
MD conduit with Building wire
Why not TPS?
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Industrial Installations
Cable Ladder/tray
Steel Conduit
Steel Wire Armour
SWA Cable is more Expensive than Steel Conduit so
why is more commonly used?
MIMS
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Exercise 1
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Planning Arranging Circuits
Why do we break the installation up into circuits?
Why not put all the loads on one or two circuits?
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Circuits
How many? What size?

• Reduce the inconvenience in the event of a fault
• Safe inspection, testing maintenance
• Unwanted nucence tripping
• Fault protection.

Different loads require different tripping times
AS/NZS 3000 Clause 1.6.1
AS/NZS 3000 Clause 2.6.2.1
AS/NZS 3000 Clause 1.5.5.3
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Circuits
How many? What size?

• The current required by each load
• The nature usage of each load
• Economics
• Flexibility of the installation

The smaller the cable the cheaper
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Loading Of The Circuit
To major factors that have to be considered

• The power requirement of the load
• How the load is used

If used for more than 15 minutes it is considered
an Extended Period
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Example 1
Circuit requirements for a 4.8kW 230 Volt HWS
Maximum current
20A
Will it be used for extended periods?
On its own circuit?
Or with other loads on one circuit?
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Example 2
Circuit requirements for two 4.8kW 230 Volt HWS
4mm2 TE 2.50/m 2.5mm2 TE 0.85/m
Cheaper to make two circuits
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Example 3
Commercial installation
Containing 45 x 60W light fittings
Are the lights likely to be all operating at the
same time?
11.7A
Protection will eventually trip. 2 Circuits are
required
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Example 3
Commercial installation
Containing 45 x 60W light fittings
Are the lights likely to be all operating at the
same time?
11.7A
Protection will eventually trip. 2 Circuits are
required
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Example 3
Domestic installation
Are the lights likely to be all operating at the
same time?
11.7A
Would the protection trip if all the lights were
on for a short period?
AS/NZS 3000 Clause 2.5.3.1
Would the cable be damaged if all the lights were
on for a short period?
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Socket Outlets
Do we put more than 1 double socket outlet on a
single circuit?
What is the minimum size cable that we can
generally use?
AS/NZS 3000 Table 3.3
AS/NZS 3000 Table C8
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Known Loads Connected To Socket Outlets
What type of loads are in the kitchen and laundry
of a house?
Would you put all these loads on the one circuit?
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Exercise 2
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Maximum Demand

• The Current that is normal expected by this type
  of load

Average Current
AS/NZS 3000 Clause 1.6.3
AS/NZS 3000 Clause 2.2.2
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Maximum Demand

• By
• Calculation
• Assessment
• Measurement
• Limitation

• Calculation Using
• Appendix C
• HB 301

15 minutes Extended Period
AS/NZS 3000 Clause 1.6.1 (b)
Must be negotiated with user
Consumer Sub-main size can be determined by sum
of the individual outgoing protection devices
82A
10A
16A
16A
20A
20A
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Maximum Demand

• Maximum Demand Value
• AMPS

Installation Type
Protection Requirements
Cable Size
Length of Run
Voltage Drop
Fault Loop
Fault Level