Maximum Demand Calculator with Examples AS/NZS 3000

Number of light points per phase.

X X X

Number of sockets per phase.

X X X

Number of sockets per phase.

X X X

Connected load in A per phase.

A A A

Connected load in A per phase.

A A A

Calculator Description

Free online Maximum Demand Calculator of Electricity for Australia and New Zealand, according to Table C1 in AS/NZS 3000.

Currently supports the following installations:

Single domestic electrical installations.
Individual living units in a complex.

Non-domestic applications will be added at a later stage.

Calculator Parameters

Load Group:
- Select the load group from the drop-down menu.
- The load groups are described in Table 1 below.
- You can use the same load group multiple times.
Red, White and Blue phase input (A or X):
- The X or A after the phase input field indicates what to use.
  - X = number of loads.
  - A = conected load.

Single-phase installations

Choose one phase for all inputs, for example, the Red phase.
Ignore the other two phases.

Three-phase installations:

Single-phase loads: Distribute evenly across the three phases.
Single-phase loads: Non-motor loads in the same load group, can be entered in the same line. They do not have to be the same number or value. Motors must be seperate!
Three-phase loads: Enter the same current value in the red, white and blue phase input fields.

How to calculate maximum demand of electricity?

The maximum demand of electricity in Australia and New Zealand is calculated according to Tables C1 and C2 in AS/NZS 3000. Table C1 is for domestic applications, and Table C2 is for commercial applications. Table 1 below is based on Table C1 (column 1) and it shows how to calculate the maximum demand for single domestic electrical installations.

Maximum Demand Formulas for Single Domestic Electrical installations.

Table 1 below is based on Table C1 (column 1) in AS/NZS 3000. However, the layout in Table 1 is different, and I have used my own words. I also added a few specific loads to simplify the calculator. The formulas and the calculated result is the same as the standard though. I suggest you refer to the standard for the original text.

Table 1: Maximum Demand Formulas for Single Domestic Electrical installations.
Load Group	Description
ai) Lighting, general	Input: Number of light points per phase. Formula: 3 A for first 20 points. Plus 2 A for each additional 20 points, or any part of it. Include dedicated lighting socket outlets higher than 2.3 m. Lighting track = 2 points/m.
aii) Lighting, outdoor > 1000W	Input: Connected load in A per phase. Formula: 75% connected load Lighting track = 0.5 A/m.
bi) Socket-outlet, general use ≤ 10A	Input: Number of sockets per phase. Formula: 10 A for first 20 points. Plus 5 A for each additional 20 points, or any part of it.
bii) Socket-outlet, general use ≤ 15A	Input: Number of sockets per phase. Formula: 10 A for 1 or more sockets. If there is a 20 A socket in the same phase, 15 A is used for both. Exclude socket-connected cooking and laundry equipment > 10 A.
biii) Socket-outlet, general use ≤ 20A	Input: Number of sockets per phase. Formula: 15 A for 1 or more sockets. If there is a 15 A socket in the same phase, 15 A is used for both. Exclude socket-connected cooking and laundry equipment > 10 A.
c) Cooking, range > 10A c) Cooking, other > 10A	Input: Connected load in A per phase. Formula: 50% connected load. Include socket connected equipment here. A range is typically a stove with hotplates on top. It does not matter what you call it. If it is used for cooking, and its > 10A, use this load group.
c) Laundry, appliance > 10A	Input: Connected load in A per phase. Formula: 50% connected load. Include socket connected equipment here. Washing machine or dryer.
d) HVAC, Airconditioning > 10A d) HVAC, Heating > 10A	Input: Connected load in A per phase. Formula: 75% connected load. General Air conditioning, Space heating, and Sauna heating. Include socket connected equipment here.
e) Water heater, instantaneous	Input: Connected load in A per phase. Formula: 33.3% connected load. Include quick recovery heaters when element rating > 100 W/litre.
f) Water heater, storage	Input: Connected load in A per phase. Formula: 100% connected load. Include quick recovery heaters when element rating ≤ 100 W/litre.
g) Water heater, pool or spa	Input: Connected load in A per phase. Formula: Largest swimming pool, 75% connected load. Largest spa, 75% connected load. Remaining water heaters, 25% connected load. Swimming pool or spa heater. This calculator supports only one swimming pool heater and one spa heater. If you need to use more, you can include them under "m) Other, appliances > 5A", and apply the diversity yourself.
jiv) Charging, electric vehicle	Input: Connected load in A per phase. Formula: 100% connected load
k) Motor, lift	Input: Connected load in A per phase. Formula: Largest lift motor, 125% connected load. Next largest lift motor, 75% connected load. Remaining lift motors, 50% connected load. Connected load current means when lifting maximum rated load at rated maximum speed. This calculator supports only one lift motor. If you need to use more, you can include them under "m) Other, appliances > 5A", and apply the diversity yourself.
l) Motor, general	Input: Connected load in A per phase. Formula: Largest motor, 100% connected load. Remaining motors, 50% connected load. Include socket connected motors. Include pool pump motors. Exclude lift motors.
m) Other, appliances > 5A	Input: Connected load in A per phase. Formula: Self-assess the maximum demand. Worse-case, use the connected load. Examples: Pottery kiln, welding machine, radio transmitter, etc. Permanently connected appliances > 5A. Ignore if the load is ≤ 5A.

Maximum Demand Examples

Example 1: Single-phase, House, 3 Bedroom, 1 Bathroom, 1 Carport.

25 General lighting points. Including outdoor lights.
22 Socket outlets (10A ), i.e. 11 double socket arrangements.
1 Cooking range (Stove), 6.9 kW at 230 V.
1 Ducted air conditioner. 10 kW cooling and 11.2 kW heating. Maximum current 20A.

Input values

Load group	Red phase
ai) Lighting, general	25 points
bi) Socket-outlet, general use ≤ 10A	22 points
c) Cooking Range (Stove) > 10A	30 A
d) HVAC, Airconditioning > 10A	20 A

The current for the air conditioner is from the manufacturer's specification. It is not calculated from the cooling or heating kilowatt rating, because a reverse cycle air conditioner uses less electricity relative to the cooling or heating power.

Laundry equipment is not listed separately. They are included in "bi) Socket-outlet, general use ≤ 10A", because they are < 10A.

After diversity maximum demand

Load group	Red phase
ai) Lighting, general 3A + 2A	5 A
bi) Socket-outlet, general use ≤ 10A 10A + 5A	15 A
c) Cooking Range (Stove) > 10A 30A × 0.5	15 A
d) HVAC, Airconditioning > 10A 20A × 0.75	15 A
Total	50 A

Example 2: Single-phase, Clubhouse with Tennis Court.

24 General lighting points. Excluding tennis court lights.
10 Meter lighting track.
9 Single socket outlets (10A).
8 Double socket outlets (10A).
1 Single socket outlet (15A)
1 50 W exhaust fan.
1 1000 W strip heater.
1 Cooking range (Stove), 10 kW at 230 V.
1 Water heater, 4.8 kW at 230 V.
1 Tennis court lighting, 3kW

Input values

Load group	Red phase
ai) Lighting, general	45 points
aii) Lighting, outdoor > 1000W	13 A
bi) Socket-outlet, general use ≤ 10A	25 points
bii) Socket-outlet, general use ≤ 15A	1 point
c) Cooking Range (Stove) > 10A	43.5 A
f) Water heater, storage	20.9 A

Lighting track is included as 2 lighting points per meter.

The exhaust fan is included as a lighting point, because it is < 60 W and it is switched on and off with a light switch.

After diversity maximum demand

Load group	Red phase
ai) Lighting, general 3A + 2A + 2A	7 A
aii) Lighting, outdoor > 1000W 13A × 0.75	9.8 A
bi) Socket-outlet, general use ≤ 10A 10A + 5A	15 A
bii) Socket-outlet, general use ≤ 15A	10 A
c) Cooking Range (Stove) > 10A 43.5 × 0.5	21.8 A
f) Water heater, storage 20.9A × 1.0	20.9 A
Total	85 A

Example 3: 3-Phase, House

25 General lighting points.
20 Double socket outlets (10A).
2 Single socket outlet (15A)
1 15 kW 3-phase range. With 7 kW oven, and two 4 kW hotplates.
1 7.5 kW Single-phase split unit air conditioner, with a maximum current of 15 A.
1 12 kW 3-phase instantaneous water heater.
1 3.8 kW single-phase laundry dryer connected to its own dedicated 20 A socket.

Input values

Load group	Red phase	White phase	Blue phase
ai) Lighting, general	25 points
bi) Socket-outlet, general use ≤ 10A	10 points	10 points
bii) Socket-outlet, general use ≤ 15A			2 points
c) Cooking Range (Stove) > 10A	30.4A
c) Cooking, other > 10A		17.4A	17.4A
c) Laundry, dryer > 10A			16.5A
d) HVAC, Airconditioning > 10A		15A
e) Water heater, instantaneous	17.4A	17.4A	17.4A

After diversity maximum demand

Load group	Red phase (A)	White phase (A)	Blue phase (A)
ai) Lighting, general Red: 3A + 2A	5
bi) Socket-outlet, general use ≤ 10A Red: 10A White: 10A	10	10
bii) Socket-outlet, general use ≤ 15A Blue: 10A			10
c) Cooking Range (Stove) > 10A Red: 30.4A × 0.5	15.2
c) Cooking, other > 10A White: 17.4A × 0.5 Blue: 17.4A × 0.5		8.7	8.7
c) Laundry, dryer > 10A Blue: 16.5A × 0.5			8.3
d) HVAC, Airconditioning > 10A White: 15A × 0.75		11.3
e) Water heater, instantaneous Red: 17.4A × 0.33 White: 17.4A × 0.33 Blue: 17.4A × 0.33	5.8	5.8	5.8
Total	36 A	36 A	33 A