Maximum Demand Calculator with Examples AS/NZS 3000
Free online maximum demand calculator of electricity for Australia and New Zealand, according to AS/NZS 3000. Includes Formulas and Examples.
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Contents
- Parameters
- How to calculate maximum demand?
- Formulas for domestic electrical installations.
- Examples for domestic electrical installations.
- Example 1: Single-phase, house, 3 bedroom, 1 bathroom, 1 carport
- Example 2: Single-phase, club-house with tennis court.
- Example 3: Three-phase, house
Parameters
- Application: Select your application.
- Load type: Select the load type from the drop-down menu. Each load type maps to a load group in AS/NZS 3000. The load types and groups are described in Table 1 below. You can use the same load type multiple times.
- Red, White and Blue phase (A or x): Specify the number of loads (x) or the connected load (A) as indicated.
- Single-phase installations: Choose one phase for all inputs, and ignore the other two phases. For example, use only the red phase.
- Three-phase installations: Distribute single-phase loads evenly across the three phases. Single-phase motor loads must be on seperate lines. Other single-phase loads of the same type, can be entered in the same line. The values can be different per phase. Three-phase loads must have the same value in all three phases.
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.
Maximum Demand Formulas for single domestic electrical installations.
Table C1 below is based on Table C1 (column 1) in AS/NZS 3000. It shows how to calculate the maximum demand for single domestic electrical installations.
Note that the layout in Table C1 below is different from the standard, and I have re-phrased it in my own words.
I also added a few specific load types to simplify the calculator. The formulas and the calculated result is the same as the standard.
Load Group | Description |
---|---|
ai) Lighting, general |
Input: Number of light points per phase. Formula:
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:
|
bii) Socket-outlet, general use ≤ 15A |
Input: Number of sockets per phase. Formula:
|
biii) Socket-outlet, general use ≤ 20A |
Input: Number of sockets per phase. Formula:
|
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:
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:
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:
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 for single domestic installations.
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, club-house 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: Three-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 |