Post on 23-Jan-2016
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LSEGG307A9080F
• 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 Maximum Demand Demand
Non-DomesticNon-Domestic
Load are generally heavier
Stay on for longer periods of time
Heating & cooling has an effect on load
ResidentiaResidential Instillationsl Instillations
• Hotels
• Boarding Houses
• Hospitals
• Motels
• etc
AS/NZS 3000Table C2Colum 2
ResidentiaResidential Instillationsl Instillations
AS/NZS 3000Table C2Colum 2
Lighting Load group A
75% connected load
Note BIncandescent Lamps = 60W
Unless the fitting restricts the wattage to less
Track lights = 0.5A/m
ResidentiaResidential Installationsl Installations10A Power Points
Load group B
If this section of buildingDOES NOT HAVE
fixed heating/cooling
Load Group Bi
20 Double power points20 x 2 = 40 Points 1000W + (39 x 400W) =
First Point
Balance
16600230 = 72.2A
ResidentiaResidential Installationsl Installations10A Power Points
Load group B
If this section of buildingDOES NOT HAVE
fixed heating/cooling
Load Group Bi
20 Double power points20 x 2 = 40 Points 1000W + (39 x 100W) =
First Point
Balance
4900230 = 72.2A
HAS
Load Group Bii
21.3A1000W + (39 x 400W) =16600230 =
ResidentiaResidential Installationsl Installations
Load group Biii
1st = full current of highest
2 x 20A power points2 x 15A power points
Power Points Larger than 10A
2nd = 50% x full current
3rd = 50% x full current
20A0.5 x 20 = 10A
0.5 x 15A = 7.5A0.5 x 15A = 7.5A
45A
ResidentiaResidential Installationsl Installations
Power Points 3 Outlets
Load Group B
10A 3 Outlet
A1 Point
B C1 Point 1 Point
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
An air conditioned motel consists of the following:A
A
A
Bii
Bii
Biii
Bii
((30x60)230)x0.75 = 5.87A
17.4A
23.3A
A
B
C
A
B
C
A
B
C
7.83A
21.7A
7.83A
34.3A
((6x400)230)x0.75 =
31P(1000+(30x100))230 =
11+30P(1000+(40x100))230 =
(1000230)+15+((2x15)x0.5) =
29.5A 42.1A
((40x60)230)x0.75 =
NSW S&IRClause 1.10.3
Less than 25A difference
FactoriesFactories
• Shops
• Offices
• Schools
• Churches
AS/NZS 3000Table C2Colum 3
FactoriesFactories
AS/NZS 3000Table C2Colum 3
Lighting Load group A
100% connected load
Note BIncandescent Lamps = 60W
Unless the fitting restricts the wattage to less
Track lights = 0.5A/m
FactoriesFactories
10A Power Points Load group B
If this section of buildingDOES NOT HAVE
fixed heating/cooling
Load Group Bi
20 Double power points20 x 2 = 40 Points 1000W + (39 x 750W) =
First Point
Balance
30250230 = 131.5A
Calculation Assessment Measuremen
t Limitation
AS/NZS 30002.2.2.
FactoriesFactories
10A Power Points Load group B
If this section of buildingDOES NOT HAVE
fixed heating/cooling
Load Group Bi
20 Double power points20 x 2 = 40 Points 1000W + (39 x 100W) =
First Point
Balance
4900230 = 131.5A
HAS
Load Group Bii
21.3A1000W + (39 x 750W) =30250230 =
FactoriesFactories
Load group Biii
1st = full current of highest
2 x 20A power points2 x 15A power points
Power Points Larger than 10A
2nd = 75% x full current
3rd = 75% x full current
20A0.75 x 20 = 15A
0.75 x 15A = 11.25A0.75 x 15A = 11.25A
57.5A
3 x 20A 3 WeldersMajority of welders only use 2 phases
W 3
A B C
Only 2 welders on each phase
AS/NZS 3000C2.5.2.2 (b)
20A + 20A = 40 Amps Per Phase
W 1 W 2
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
10 metre x 10 metre air conditioned shop
From C310 x 10 = 100 m2
Light & power (average value)= 70 VA/m2
Air conditioning= 30 VA/m2
100 VA/m2
100 m2 x 100 VA/m2 = 10kVA
400 x √3= 14.4A /
• Single items on circuit
• Multiple items on circuit
• Diversity may be applied
Current rating of appliance
Limit by circuit breaker
• Welders• Domestic cooking appliances
Final Sub-circuits
• Arc Welding Machines• Stick• MIG• TIG
Types
1st Machine2nd
3rd
4th
5th + more
100%100%85%70%60%
Highest
Lowest
• Rated Primary Current• Actual Primary Current
• Arc Welding Machines
• Resistance Welding Machines
• Stick• MIG• TIG
Spot welders
Types
• Rated Primary Current• Actual Primary current• Duty Cycle
• 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
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 secondsOff for 30 seconds 30/30 =50% Duty Cycle
• 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
1st Machine2nd + More
100%60%
Highest
Lowest
Table C4
4.8kW wall oven =6.8kW wall oven =
9kW wall oven + 4.8kW hotplate =
16A20A13.8kW = 40A
TEST