# ELECTRICAL INSTALLATION PLANNING

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ELECTRICAL INSTALLATION PLANNING
LSEGG307A 9080F

Lesson Content Describe the acceptable methods for determining the maximum demand on an installation’s consumer’s mains. Calculate the maximum demand for the consumer's mains for given installations up to 400 A per phase.

Maximum Demand Non-Domestic
Load are generally heavier Stay on for longer periods of time Heating & cooling has an effect on load

Residential Instillations
Hotels Boarding Houses Hospitals Motels etc AS/NZS 3000 Table C2 Colum 2

Residential Instillations
Lighting AS/NZS 3000 Table C2 Colum 2 Load group A 75% connected load Note B Incandescent Lamps = 60W Unless the fitting restricts the wattage to less Track lights = 0.5A/m

Residential Installations
10A Power Points Load group B If this section of building DOES NOT HAVE fixed heating/cooling Load Group Bi 20 Double power points 72.2A 20 x 2 = 40 Points 1000W + (39 x 400W) = 16600230 = First Point Balance

Residential Installations
10A Power Points Load group B If this section of building DOES NOT HAVE fixed heating/cooling HAS Load Group Bii Load Group Bi 20 Double power points 21.3A 72.2A 20 x 2 = 40 Points 1000W + (39 x 100W) = 1000W + (39 x 400W) = 16600230 = 4900230 = First Point Balance

Residential Installations
Power Points Larger than 10A Load group Biii 1st = full current of highest 2nd = 50% x full current 3rd = 50% x full current 2 x 20A power points 2 x 15A power points 20A 0.5 x 20 = 10A 0.5 x 15A = 7.5A 45A

Residential Installations
Power Points 3 Outlets Load Group B 10A 3 Outlet A B C 1 Point 1 Point 1 Point

An air conditioned motel consists of the following:
Exercise 1 An air conditioned motel consists of the following: A Bii Biii A B C 30 x Light points 40 x Lights 6 x 400W mercury vapour flood lights 15 x Double power points (p/p) 10 x Single p/p & 15 x Double p/p 3 x 15A Single p/p 1 x 10A 3 outlet ((30x60)230)x0.75 = 5.87A 17.4A ((40x60)230)x0.75 = 7.83A 21.7A ((6x400)230)x0.75 = 7.83A 34.3A 31P (1000+(30x100))230 = 11+30P (1000+(40x100))230 = (1000230)+15+((2x15)x0.5) = 23.3A 29.5A 42.1A NSW S&IR Clause Less than 25A difference

Factories Shops Offices Schools Churches AS/NZS 3000 Table C2 Colum 3

Factories Lighting Note B AS/NZS 3000 Table C2 Colum 3 Load group A
100% connected load Note B Incandescent Lamps = 60W Unless the fitting restricts the wattage to less Track lights = 0.5A/m

Factories 10A Power Points Load Group Bi AS/NZS 3000 2.2.2.
Calculation Assessment Measurement Limitation Load group B If this section of building DOES NOT HAVE fixed heating/cooling Load Group Bi 20 Double power points 131.5A 20 x 2 = 40 Points 1000W + (39 x 750W) = 30250230 = First Point Balance

If this section of building DOES NOT HAVE fixed heating/cooling HAS Load Group Bii Load Group Bi 20 Double power points 21.3A 131.5A 20 x 2 = 40 Points 1000W + (39 x 100W) = 1000W + (39 x 750W) = 30250230 = 4900230 = First Point Balance

Factories Power Points Larger than 10A Load group Biii
1st = full current of highest 2nd = 75% x full current 3rd = 75% x full current 2 x 20A power points 2 x 15A power points 20A 0.75 x 20 = 15A 0.75 x 15A = 11.25A 57.5A

Only 2 welders on each phase
AS/NZS 3000 C (b) 3 x 20A 3 Welders Majority of welders only use 2 phases B A C Only 2 welders on each phase W 1 W 2 W 3 20A + 20A = 40 Amps Per Phase

C3 Commercial & Light industrial
Used to give a “Ball Park” figure of maximum demand when actual loads are not available in the initial design stages Values are given in VA per m2 of floor area

C3 Commercial & Light industrial
10 metre x 10 metre air conditioned shop 10 x 10 = 100 m2 From C3 Light & power (average value)= 70 VA/m2 Air conditioning= 30 VA/m2 100 VA/m2 100 m2 x 100 VA/m2 = 10kVA = 14.4A / 400 x √3

Maximum Demand Final Sub-circuits Single items on circuit
Multiple items on circuit Diversity may be applied Current rating of appliance Limit by circuit breaker Welders Domestic cooking appliances

Welding Machines Types Arc Welding Machines Stick MIG TIG Highest
1st Machine 2nd 3rd 4th 5th + more 100% 85% 70% 60% Lowest Rated Primary Current Actual Primary Current

Welding Machines Types Arc Welding Machines Stick MIG TIG
Resistance Welding Machines Stick MIG TIG Spot welders Rated Primary Current Actual Primary current Duty Cycle

Resistance Welding Machines
Individual Machines Variable Operation Specific (fixed) Operation Seam welders Auto feed welders Manual welders Non-Auto Welders 70% 50% x Rated Primary Current Actual Primary current x Multiplier

Duty Cycle Ratio of ON TIME/OFF TIME in 1 minute 30/30 =
Very few welders operate at 100% all of the time Changing the electrodes Repositioning the job Starting a new job Ratio of ON TIME/OFF TIME in 1 minute Weld for 30 seconds Off for 30 seconds 30/30 = 50% Duty Cycle

Resistance Welding Machines
Individual Machines Groups of machines Variable Operation Specific (fixed) Operation Seam welders Auto feed welders Manual welders Non-Auto Welders 70% 50% x Rated Primary Current Actual Primary current x Multiplier Highest 1st Machine 2nd + More 100% 60% Lowest

Domestic Cooking Appliances
Table C4 4.8kW wall oven = 6.8kW wall oven = 9kW wall oven + 4.8kW hotplate = 16A 20A 13.8kW = 40A

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