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