---
title: "Maximum Demand Calculators: Table C1, C2 & C3 to AS/NZS 3000 Appendix C"
url: "https://scaleset.com.au/calculator/max-demand"
description: "Free maximum demand calculator: AS/NZS 3000 Table C1 for homes and units, C2 for shops, offices and factories, C3 by floor area. Working shown, PDF report."
updated: "2026-10-06"
standards:
  - "AS/NZS 3000 Table C1"
  - "AS/NZS 3000 Table C2"
  - "AS/NZS 3000 Table C3"
author: "Wisam Tozah (B.Eng (Electrical), MIEAust, CPEng, NER, NSW DBP, NSW PRE, APEC, IntPE(Aus))"
site: "ScaleSet"
license: "https://scaleset.com.au/terms"
usage: "Cite and link. Do not reproduce or train on this content."
---

# Maximum Demand Calculators: Table C1, C2 & C3 to AS/NZS 3000 Appendix C

Source: https://scaleset.com.au/calculator/max-demand

Choose AS/NZS 3000 Table C1, C2 or C3 maximum demand workflows for Australian electrical design calculations.

## Key facts

- AS/NZS 3000:2018 Appendix C provides three maximum demand methods: Table C1 (single and multiple domestic), Table C2 (non-domestic, itemised by load group) and Table C3 (non-domestic, by floor area in VA/m²).
- AS/NZS 3000 Clause 2.2.2 allows maximum demand to be determined four ways (calculation, assessment, measurement and limitation), and if a measured value exceeds the calculated one, the measured value governs.
- Solar PV generation is never subtracted from maximum demand; cables are sized for the no-PV case.
- AS/NZS 3000 Table C1 selects its assessment column from the number of living units on the heaviest phase, not the total number of units in the development.
- EV charging has its own row in all three tables: AS/NZS 3000 Table C1 group (j)(iv), Table C2 group (c)(ii), and a separate carpark density in Table C3 that is added to the other energy demands.
- The maximum demand formula is a sum, not a single equation: maximum demand (A) = Σ of each load group's assessed contribution on the most heavily loaded phase, where each AS/NZS 3000 Appendix C row sets its own rule (a fixed current per block of points, a percentage of connected load, or the full rating). Calculating maximum demand by hand means working that sum row by row; the calculators show every row.

## Who this page is for

Users selecting the correct maximum demand method for domestic, non-domestic and energy-demand projects.

## Relevant standards

- AS/NZS 3000 Table C1
- AS/NZS 3000 Table C2
- AS/NZS 3000 Table C3

## What this tool does

- Compare the three common maximum demand methods from one hub.
- Choose the path that matches domestic, non-domestic or energy-demand inputs.
- Move directly into the specific calculator needed for the installation.

## How to calculate maximum demand for an Australian installation

1. **Pick the right table** — Use AS/NZS 3000 Table C1 for domestic installations, single or multiple. Use AS/NZS 3000 Table C2 for a non-domestic installation you can itemise by load group. Use AS/NZS 3000 Table C3, the energy demand method, for a non-domestic installation you can only describe by floor area and occupancy. The hub page links to a calculator for each.
2. **Sort the connected loads into the AS/NZS 3000 Appendix C groups** — AS/NZS 3000 Table C1 uses load groups (a) to (m): lighting, socket-outlets, cooking, heating and air conditioning, water heating, spa and pool, then the communal groups, lifts, motors and other appliances by assessment (over 5 A in a dwelling, over 10 A communal). AS/NZS 3000 Table C2 uses groups (a) to (j). Enter connected load, not an already-diversified figure: the table applies the diversity.
3. **Set the column the table will be read against** — AS/NZS 3000 Table C1 selects its column from the living units on the heaviest phase: Column 2 for a single domestic installation, Column 3 for 2 to 5 units per phase, Column 4 for 6 to 20, Column 5 for 21 or more. AS/NZS 3000 Table C2 selects between its two occupancy columns. AS/NZS 3000 Table C3 needs the floor area and the occupancy type.
4. **Add EV charging in the right row** — EV charging is load group (j)(iv) in AS/NZS 3000 Table C1, group (c)(ii) in Table C2, and a separate carpark density in Table C3 that is added to the other energy demands. Do not fold charger load into a general appliance or socket-outlet row.
5. **Do not subtract solar PV** — PV generation is not subtracted from the AS/NZS 3000 Appendix C result. The consumer mains must be sized for the no-PV case so it can carry full grid-import current if the inverter trips.
6. **Check the result against the distributor rules** — AS/NZS 3000 does not set a minimum consumer mains current: minimum sizes come from the local distributor's service and installation rules. Compare the AS/NZS 3000 Appendix C figure against your DNSP's requirements before sizing the cable.
7. **Export the PDF report** — Downloading it needs a free account. The report lists every AS/NZS 3000 Appendix C load group used, the column or expression applied, and the resulting per-group contribution: ready for the design submission package.

## Maximum demand under AS/NZS 3000:2018 Appendix C: Tables C1, C2 and C3

### What is maximum demand and why does AS/NZS 3000 require it?

Maximum demand is the highest current an installation is expected to draw on a sustained basis, obtained by applying diversity to the connected load. AS/NZS 3000:2018 Clause 2.2.2 requires the maximum demand in consumer mains, submains and final subcircuits to be determined (taking account of how the equipment is distributed and used), because real installations almost never draw their full connected load at once.

AS/NZS 3000 Clause 2.2.2 permits four methods: (a) calculation, using the guidance in the Standard for the type of installation; (b) assessment, where loads fluctuate, are intermittent, follow a duty cycle, or the installation is large, complex or a special occupancy; (c) measurement, taken as the highest consumption sustained over a 30-minute period; and (d) limitation, by the current rating or setting of the protective device. If a measured maximum demand turns out to exceed the calculated or assessed figure, the measured value is deemed to be the maximum demand.

AS/NZS 3000 Appendix C is the guidance for method (a). It provides three tabulated routes: AS/NZS 3000 Table C1 for single and multiple domestic installations, Table C2 for non-domestic installations assessed by itemised load group, and Table C3, the energy demand method, which assesses a non-domestic installation from its floor area in volt-amperes per square metre.

### Which table applies to which installation

AS/NZS 3000 Table C1 applies to consumer mains and submains serving a single dwelling or a block of living units, including the communal lighting, socket-outlets, appliances, lifts and motors that serve the block. Its four demand columns are selected by the number of living units on the heaviest phase: Column 2 for a single domestic installation or one unit per phase, Column 3 for 2 to 5, Column 4 for 6 to 20 and Column 5 for 21 or more.

AS/NZS 3000 Table C2 applies to non-domestic installations and has two occupancy columns: Column 2 for residential institutions, hotels, boarding houses, hospitals, accommodation houses and motels, and Column 3 for factories, shops, stores, offices, business premises, schools and churches. Its ten load groups run from lighting and socket-outlets through appliances and EV charging, motors, lifts, fuel dispensing, thermal storage, welding and X-ray equipment.

AS/NZS 3000 Table C3 is the energy demand method for non-domestic installations. It gives a VA/m² range and average for each tabulated occupancy (offices, retail shops, warehouses, light industrial, carparks, taverns and licensed clubs, and theatres), so the demand can be assessed from floor area before the equipment schedules exist. Air conditioning is tabulated separately from light and power, and EV charging is added on top of the other energy demands.

### When the choice of table changes the result

A mixed-use building (ground floor retail, upper floors residential) uses AS/NZS 3000 Table C2 or Table C3 for the retail submain and Table C1 for the residential submains, summed at the main switchboard. The AS/NZS 3000 Table C1 communal load groups (h) to (m) cover the block's own lighting, laundry, lifts and motors, and AS/NZS 3000 Table C1 refers lifts back to Paragraph C2.4.1 and Table C2 for their assessment.

EV charging appears in every table but in a different place: load group (j)(iv) in AS/NZS 3000 Table C1, assessed at full connected load for a single domestic installation and at 100%, 90% or 75% of connected load by column for a block of units; load group (c)(ii) in AS/NZS 3000 Table C2, assessed at the full connected load of the highest-rated unit plus 75% of the remainder; and a separate carpark density in AS/NZS 3000 Table C3 that the table explicitly says is to be considered in addition to all other energy demands.

Solar PV generation is not subtracted from maximum demand for cable sizing under AS/NZS 3000: the cable must be sized for the no-PV case so it can carry full grid-import current if the inverter trips or the array is not generating.

### How ScaleSet implements AS/NZS 3000 Appendix C

The ScaleSet suite implements all three tables: AS/NZS 3000 Table C1 with load groups (a) to (m) and automatic column selection from the living units per phase, Table C2 with load groups (a) to (j) and both occupancy columns, and Table C3 with the tabulated VA/m² densities available as per-occupancy presets. Each calculator returns a line-by-line breakdown showing the group, the input, the expression applied and the resulting current, and exports it as a PDF report (a free account to download) so the calculation can be re-checked row by row during compliance review.

Use this hub to pick the table that matches the installation. Note that AS/NZS 3000 does not itself specify a minimum consumer mains current: minimum sizes come from the local distributor's service and installation rules, so check the AS/NZS 3000 Appendix C result against your DNSP's requirements before selecting the cable.

### Worked example: a single-phase house to AS/NZS 3000 Table C1

### What the house example shows

Without the charger the house sits at 74 A, inside a standard 80 A or 100 A single-phase service. The 32 A charger, counted at full load as AS/NZS 3000 Table C1 group (j)(iv) and Appendix P Paragraph P2 require, takes it to 106 A, and the consumer mains, the service fuse and the distributor's connection all have to follow. There are three ways out, and the calculator lets you test each: a three-phase supply, which spreads the loads and puts the charger on one phase at 32 A; a smaller charger (a 16 A unit adds 16 A instead of 32 A); or AS/NZS 3000 Clause 2.2.2(d) limitation, where a dynamic load management system holds the charging current below a set value and the demand is the set value, not the nameplate.

The socket-outlet rows are where most hand calculations go wrong. A double socket-outlet is two points (Note 8), every permanently connected appliance not exceeding 10 A is one more point in group (b)(i) (Note 9), and a 15 A or 20 A socket-outlet adds a flat 10 A or 15 A to the base loading once (Note 10), not per outlet. The calculator counts the points and applies the notes.

### Worked example: 24 units on a three-phase supply

### What the block example shows

The consumer mains and the main switch are sized for 239 A per phase, so 250 A. The two EV chargers on the heaviest phase are a quarter of that, which is why the number of chargers, their rating and how they are spread across the phases now matter as much as the unit count. In Column 5 (21 or more units per phase) the same chargers are counted at 75%, and in Column 3 (2 to 5 units per phase) at 100%.

The rows connected to individual units use the column; the communal rows do not. Communal lighting, communal socket-outlets, lifts and motors are assessed at their own rule whatever the unit count, and the lift and motor groups (k) and (l) send you to AS/NZS 3000 Table C2 Column 2 for the figure. The calculator holds the unit rows and the communal rows apart and shows both sums before it adds them.

### AS/NZS 3000 Table C4: switchboard diversity from circuit-breaker ratings (Amendment 3)

### Assessment, measurement and limitation: the other three methods

AS/NZS 3000 Appendix C is the calculation method of Clause 2.2.2(a), and the clause offers three more. Assessment (b) is for fluctuating or cyclic loads, large and complex installations and special occupancies, and it is the route for a factory or a hospital where the AS/NZS 3000 Appendix C tables were never meant to fit. Measurement (c) uses the highest demand recorded over any 30 minute period, which is why a metered existing building can be assessed from twelve months of interval data rather than re-calculated; the clause also says that if the measured demand ever exceeds the calculated one, the measured value governs. Limitation (d) uses the setting of the circuit-breaker: a fixed 80 A device, or an adjustable device set to a value, fixes the demand at that value.

Limitation is what makes EV load management work. AS/NZS 3000 Table C1 and Table C2 count a charger at full connected load and AS/NZS 3000 Appendix P Paragraph P2 says every connecting point is used at its full rated current at the same time, so the tables alone give no diversity for chargers. A load management system that caps the total charging current at, say, 60 A behind a 63 A device is limitation under AS/NZS 3000 Clause 2.2.2(d): the demand is 60 A however many chargers hang off it. The setting has to be fixed, documented and not reachable by the user, and the distributor's connection rules may ask for it to be shown on the drawings.

## Key terms

- **Maximum demand** — The highest sustained current an electrical installation is expected to draw, determined under AS/NZS 3000:2018 Clause 2.2.2 and used to size consumer mains, submains and switchgear. AS/NZS 3000 Appendix C gives the tabulated guidance for the calculation method.
- **Diversity** — The allowance for connected loads not all operating at full output simultaneously. AS/NZS 3000 Appendix C encodes diversity in each table row rather than as one blanket factor: per load group and assessment column in AS/NZS 3000 Tables C1 and C2, and within the tabulated density in Table C3.
- **AS/NZS 3000 Table C1** — The AS/NZS 3000 Appendix C method for single and multiple domestic electrical installations. Load groups (a) to (m) run down the table and four demand columns run across it, selected by the living units per phase: Column 2 (a single domestic installation or one unit per phase), Column 3 (2 to 5), Column 4 (6 to 20) and Column 5 (21 or more).
- **AS/NZS 3000 Table C2** — The AS/NZS 3000 Appendix C method for non-domestic electrical installations, with load groups (a) to (j) and two occupancy columns: Column 2 for residential institutions, hotels, boarding houses, hospitals, accommodation houses and motels, and Column 3 for factories, shops, stores, offices, business premises, schools and churches.
- **AS/NZS 3000 Table C3** — The AS/NZS 3000 Appendix C energy demand method for non-domestic installations: maximum demand assessed from floor area using tabulated volt-amperes per square metre by type of occupancy (for example offices 40 to 60 VA/m² light and power, retail shops 40 to 100, warehouses 5 to 15), with air conditioning and EV charging added separately.

## Frequently asked questions

### Which maximum demand table should I use: AS/NZS 3000 Table C1, C2 or C3?

Use AS/NZS 3000 Table C1 for a house, a unit or a block of living units; AS/NZS 3000 Table C2 for a non-domestic building whose loads you can list by load group; and AS/NZS 3000 Table C3, the energy demand method, for a commercial or light-industrial building when you know only the floor area and the occupancy, typically at concept stage before the equipment schedules exist. A mixed-use building uses AS/NZS 3000 Table C1 for the dwellings and AS/NZS 3000 Table C2 or C3 for the rest, added at the main switchboard. ScaleSet has a calculator for each of the three.

### What does AS/NZS 3000 Clause 2.2.2 require for maximum demand?

AS/NZS 3000 Clause 2.2.2 requires the maximum demand of consumer mains, submains and final subcircuits to be determined by one of four methods: calculation (using the guidance in AS/NZS 3000 Appendix C), assessment (where loads fluctuate or run to a duty cycle, or the installation is large, complex or a special occupancy), measurement (the highest consumption sustained over 30 minutes), or limitation (the rating or setting of the circuit-breaker). AS/NZS 3000 Appendix C is informative, so another sound calculation is allowed, but the figure has to be worked out. If a measured value exceeds the calculated or assessed one, the measured value is the maximum demand.

### How is EV charging added to maximum demand?

Each AS/NZS 3000 Appendix C table has its own EV row, added on top of the other loads. AS/NZS 3000 Table C1 group (j)(iv) takes the full connected load in a single house, then 100% of connected load for 2 to 5 living units per phase, 90% for 6 to 20 and 75% for 21 or more. AS/NZS 3000 Table C2 group (c)(ii) takes the full connected load of the highest-rated charger plus 75% of the rest, in both columns. AS/NZS 3000 Table C3 adds 5 to 15 VA/m² (average 10) for an open-air carpark and 10 to 30 VA/m² (average 20) for a basement, in addition to all other energy demands. Batteries have no AS/NZS 3000 Appendix C row: assess a battery from its maximum charging current from the grid (AS/NZS 3000 Clause 2.2.2(b)) and install it to AS/NZS 5139. The C1 and C2 calculators have dedicated EV inputs; in C3 the EV density goes in as its own area row.

### What is the maximum demand formula?

There is no single formula. Under AS/NZS 3000 Appendix C the maximum demand is the sum of the assessed demand of each load group, and each row of the table gives its own rule: a fixed current, an allowance per block of points or per outlet beyond the first, a percentage of connected load, or the largest item in full and the rest at a reduced share. In words: maximum demand (A) = Σ (load group contributions per AS/NZS 3000 Table C1 or C2) on the most heavily loaded phase. For AS/NZS 3000 Table C3 it is Σ (floor area × VA/m² for each occupancy row, air conditioning and EV charging included) ÷ (√3 × 400 V) per phase on a three-phase supply, or ÷ 230 V on single-phase. The calculators show every row of that sum.

### How do you calculate maximum demand for a block of units?

With AS/NZS 3000 Table C1, reading the column from the number of living units on the heaviest phase rather than the total. Note 2 to AS/NZS 3000 Table C1 divides the units by the supply phases, so 16 units on three phases is 6 on the heaviest phase and Column 4 applies. Column 2 is one unit per phase, Column 3 is 2 to 5, Column 4 is 6 to 20 and Column 5 is 21 or more; the per-unit allowances fall as the column moves right because diversity across units rises. Communal lighting, power, laundries, EV charging, lifts and motors are then added from AS/NZS 3000 Table C1's own communal groups (h) to (m), with lifts and motors assessed by AS/NZS 3000 Paragraph C2.4.1 and Table C2. The AS/NZS 3000 Table C1 calculator picks the column for you.

### How is maximum demand used to size consumer mains and submains?

The maximum demand is the design current of the consumer mains or submain. The protective device is chosen with a rating at or above it, and the cable with a current-carrying capacity at or above that rating (AS/NZS 3000 Clause 2.5.3.1, restated in Paragraph C2.1), then checked for voltage drop under AS/NZS 3000 Clause 3.6 and for its installation conditions under AS/NZS 3008.1.1. A submain is sized the same way from the maximum demand of the board it feeds. Take the figure from the C1, C2 or C3 calculator into Cable Selection to size the cable.

### Do I apply a diversity factor on top of the AS/NZS 3000 Appendix C result?

Not normally. AS/NZS 3000 Tables C1 and C2 build diversity into each load group: a share of connected load, a fixed allowance per block of points, or the largest item in full and the rest at a reduced percentage. A further overall factor is your own assessment under AS/NZS 3000 Clause 2.2.2(b) and needs a reason you can show. The ScaleSet calculators accept one, labelled as not part of the table, and print it as its own line so the AS/NZS 3000 Appendix C figure stays visible. For a switchboard built to the AS/NZS 61439 series, AS/NZS 3000 Table C4 is the standard's own diversity method.

### Is solar PV subtracted from maximum demand under AS/NZS 3000:2018?

No. The consumer mains and submains must be sized for the no-PV case so they can carry full grid-import current if the inverter trips or the array is not generating. PV output is not subtracted from the AS/NZS 3000 Appendix C maximum demand result.

### Can maximum demand be measured instead of calculated?

Yes. AS/NZS 3000 Clause 2.2.2(c) allows maximum demand to be determined by measurement: the highest rate of consumption recorded or sustained over a 30 minute period when demand is at its highest, from a maximum demand indicator or recorder. Twelve months of 30 minute interval meter data is the usual source for an existing building. Where a measured value exceeds a calculated or assessed one, the measured value is the maximum demand. Measurement is a different route from the AS/NZS 3000 Table C3 energy demand method, which works from floor area rather than metered data.

### What is the Table C4 switchboard diversity factor in AS/NZS 3000?

AS/NZS 3000 Table C4, with Paragraph C2.4.4, is an alternative method for a switchboard that conforms with the AS/NZS 61439 series: the maximum demand may be taken as the arithmetic sum of the circuit overload ratings downstream, multiplied by 0.9 for 2 or 3 protective devices, 0.8 for 4 or 5, 0.7 for 6 to 9 and 0.6 for 10 or more. It was added by Amendment 3 and suits a board whose breaker schedule is known before its equipment is.

### Can a load management system reduce maximum demand?

Yes, where the limit is set by a circuit-breaker. AS/NZS 3000 Clause 2.2.2(d) lets the maximum demand be the current rating of a fixed-setting circuit-breaker or the load setting of an adjustable one, so a group of chargers behind a breaker set at 63 A has a demand of 63 A, whatever their nameplates add up to. A software load management system that caps current is not named in the clause: record its cap as an assessment under AS/NZS 3000 Clause 2.2.2(b), and check the distributor's service and installation rules, which set their own conditions for managed load. Without either, AS/NZS 3000 Appendix P Paragraph P2 takes every EV connecting point at its full rated current, all at the same time.

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