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ELECTRICAL INSTALLATION PLANNING. LSEGG307A 9080F. Assessments. Theory Test 1 Theory Test 2 Assignments Final Examination. 10% 20% 10% 60%. Lesson Content. Protection against harmful effects Correct functioning Supply characteristics Determining Maximum demand
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ELECTRICAL INSTALLATION PLANNING LSEGG307A 9080F
Assessments Theory Test 1 Theory Test 2 Assignments Final Examination 10% 20% 10% 60%
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
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
What you will require each week • AS/NZS 3000:2007 • AS/NZS 3008 :1998 • Calculator
Lesson 1 Determining a Wiring System for an Installation
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
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
What Determines The Type of Cable System Chosen? Temperature, High Humidity, Corrosive atmospheres, Mechanical damage, etc AS/NZS 3000 1.6.1 • 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
Other Factors That An Electrician Has To Consider/Abide by :- Concealed or Surface Materials & Labor AS/NZS 3000 and other electrical standards Local supply authority standards Building codes Fire ratings Heritage orders etc Appearance Speed of installation Cost
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
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
Timber & Steel Frame TPS inside frame is most commonly used Why?
Full Brick & Concrete Slab Concrete slab = Deck work MD conduit with Building wire Why not TPS?
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
Planning & Arranging Circuits Why do we break the installation up into circuits? Why not put all the loads on one or two circuits?
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
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
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”
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?
Example 2 Circuit requirements for two 4.8kW 230 Volt HWS 4mm2 T&E = $2.50/m 2.5mm2 T&E = $0.85/m Cheaper to make two circuits
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
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
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?
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
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?
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
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
Maximum Demand Maximum Demand Value AMPS Installation Type Protection Requirements Cable Size Length of Run Voltage Drop Fault Loop Fault Level