---
title: "Maximum Demand Calculators: Table C1, C2 & C3 to AS/NZS 3000 Appendix C"
url: "https://elecas.com.au/calculator/max-demand"
description: "Free AS/NZS 3000 maximum demand calculator: Table C1 for homes and units, C2 for shops, offices and factories, C3 by floor area. Working shown, PDF report."
updated: "2026-09-11"
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: "ElecAS"
license: "https://elecas.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://elecas.com.au/calculator/max-demand

Choose Table C1, Table C2 or Table 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).
- 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.
- 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: 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 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 Table C1 for domestic installations, single or multiple. Use Table C2 for a non-domestic installation you can itemise by load group. Use 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 Appendix C groups** — 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 loads over 10 A. 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** — 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. Table C2 selects between its two occupancy columns. 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 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 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 Appendix C figure against your DNSP's requirements before sizing the cable.
7. **Export the branded PDF** — The report lists every 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.

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.

Appendix C is the guidance for method (a). It provides three tabulated routes: 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

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.

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.

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 Table C2 or Table C3 for the retail submain and Table C1 for the residential submains, summed at the main switchboard. The Table C1 communal load groups (h) to (m) cover the block's own lighting, laundry, lifts and motors, and 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 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 Table C2, assessed at the full connected load of the highest-rated unit plus 75% of the remainder; and a separate carpark density in 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 ElecAS implements Appendix C

The ElecAS suite implements all three tables: 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 branded PDF 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 Appendix C result against your DNSP's requirements before selecting the cable.

### Worked example: a single-phase house to 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 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 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 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.

### Table C4: switchboard diversity from circuit-breaker ratings (Amendment 3)

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

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 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. Table C1 and Table C2 count a charger at full connected load and 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 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. Appendix C gives the tabulated guidance for the calculation method.
- **Diversity** — The allowance for connected loads not all operating at full output simultaneously. Appendix C encodes diversity in each table row rather than as one blanket factor: per load group and assessment column in Tables C1 and C2, and within the tabulated density in Table C3.
- **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).
- **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.
- **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 40–60 VA/m² light and power, retail shops 40–100, warehouses 5–15), with air conditioning and EV charging added separately.

## Frequently asked questions

### Which AS/NZS 3000 maximum demand method should I use?

Use Table C1 for houses and blocks of units, Table C2 for a non-domestic building where you can list the actual loads, and Table C3 when you only know the floor area and the type of occupancy: typically at concept stage, before the equipment schedules exist.

### Is the maximum demand calculation mandatory?

Yes. Clause 2.2.2 says the maximum demand for consumer mains, submains and final subcircuits must be worked out: by calculation, by assessment, by measurement, or by the rating of the protective device. Appendix C is the guidance for the calculation route; it is informative, so you can use another sound method, but you cannot skip working the number out.

### Can I add EV charging and battery loads to maximum demand?

Yes for EV charging. It has its own row in each table: group (j)(iv) in Table C1, group (c)(ii) in Table C2, and a separate carpark density in Table C3. Batteries are different: AS/NZS 3000 has no battery row in Appendix C, so a battery has to be assessed on its own under Clause 2.2.2(b) using its charging current, and the installation itself follows AS/NZS 5139. The ElecAS C1 and C2 calculators have dedicated EV inputs.

### 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, a current per point beyond the first, a percentage of the connected load, or the full rating. In words: Maximum demand (A) = Σ (load group contribution per Table C1, C2 or C3) on the most heavily loaded phase. For Table C3 it is instead Σ (floor area × VA/m² for the occupancy) ÷ (line voltage × √3 for three-phase), plus air conditioning and EV charging. The calculators show every row of that sum.

### How do I calculate maximum demand for a house?

Use Table C1, Column 2. List the loads by group: lighting (group A: 3 A for the first 20 points, then 2 A for each further 20), socket outlets (group B: 10 A for the first 20 points, then 5 A for each further 20), the range and other cooking appliances over 10 A (group C: 50% of the connected load), heating and air conditioning (group D: 75%), instantaneous water heaters (group E: 33.3%), storage water heaters (group F: 100%), a spa or pool (group G: 75% of the largest motor plus 25% of the rest), and any EV charger (group J(iv): 100% of the charger rating). Add the group currents on the heaviest phase; that is the maximum demand the consumer mains are sized for. The Table C1 calculator does the arithmetic and shows each line.

### How is calculating maximum demand different for a block of units?

Table C1 changes column, not method. The column is chosen by the number of living units on the most heavily loaded phase: Column 2 for one unit per phase, Column 3 for 2 to 5, Column 4 for 6 to 20 and Column 5 for 21 or more. The per-unit allowances fall as the column moves right because diversity across units rises. Communal loads such as lifts, carpark lighting and pumps are then assessed under Table C2 and added.

### Which AS/NZS 3000 table do I use to calculate maximum demand?

Use Table C1 for single dwellings and blocks of living units, Table C2 for a non-domestic installation you can itemise by load group, and Table C3 (the energy demand method) for a non-domestic installation assessed from floor area in VA/m² when the equipment schedules do not yet exist. ElecAS provides a calculator for each.

### 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 Appendix C maximum demand result.

### What methods does AS/NZS 3000 allow for determining maximum demand?

Clause 2.2.2 permits four: calculation using the guidance in the Standard (Appendix C), assessment where loads fluctuate or the installation is large, complex or a special occupancy, measurement as the highest consumption sustained over a 30-minute period, and limitation by the rating or setting of the protective device. If the measured value exceeds the calculated or assessed value, the measured value is deemed to be the maximum demand.

### How do EV chargers affect maximum demand?

Each Appendix C table has its own EV row. Table C1 group (j)(iv) takes the full connected load for a single domestic installation, then 100% of connected load for 2 to 5 living units per phase, 90% for 6 to 20 and 75% for 21 or more. Table C2 group (c)(ii) takes the full connected load of the highest-rated charger plus 75% of the remainder. Table C3 tabulates a carpark EV charging density of 5–15 VA/m² open air and 10–30 VA/m² basement, to be added to all other energy demands.

### Can I use recorded consumption data instead of Appendix C?

Yes. 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 at the time of highest demand. Where a measured value exceeds a calculated or assessed one, the Standard requires the measured value to be treated as the maximum demand. This is a different method from the Table C3 energy demand method, which works from floor area rather than metered data.

### How much maximum demand does an EV charger add to a house?

Its full rated current. AS/NZS 3000:2018 Table C1 group (j)(iv) counts charging equipment in a single domestic installation at full connected load, and Appendix P Paragraph P2 says every connecting point is used at its full rated current, all at the same time. A 7.4 kW single-phase charger adds 32 A, which takes a typical 70 to 80 A house past a 100 A single-phase service. The alternatives are a three-phase supply, a 16 A charger, or a load management system that caps the current, which fixes the demand at the cap under Clause 2.2.2(d).

### Do EV chargers get any diversity in a block of units?

Only in the multi-unit columns. Table C1 group (j)(iv) counts EV charging equipment at 100% of connected load for 2 to 5 living units per phase, 90% for 6 to 20 and 75% for 21 or more, on the chargers connected to the heaviest phase. A single house and a non-domestic installation (Table C2 group (c)(ii)) get no diversity at all. Anything further has to come from load management, recorded as limitation under Clause 2.2.2(d).

### What is Table C4 in AS/NZS 3000?

A switchboard diversity table added by Amendment 3 (2023) with Paragraph C2.4.4. For a switchboard built to the AS/NZS 61439 series, the maximum demand may be taken as the sum of the outgoing circuit overload ratings multiplied by 0.9 for 2 or 3 devices, 0.8 for 4 or 5, 0.7 for 6 to 9 and 0.6 for 10 or more. It is a quick method for a non-domestic board whose breaker schedule is known before its equipment is.

### How is a measured maximum demand taken?

Clause 2.2.2(c) defines it as 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 interval meter data at 30 minute resolution is the usual source for an existing building. The clause adds that if the measured demand ever exceeds the calculated or assessed value, the measured value is the maximum demand.

### What is a typical maximum demand for a house in Australia?

Worked through Table C1, an all-electric four-bedroom house with a 9.6 kW cooktop and oven, a reverse-cycle air conditioner, a storage water heater and about 34 socket-outlet points comes to around 74 A single-phase. Gas cooking and hot water take it under 50 A; a 32 A EV charger adds 32 A on top. The Table C1 calculator shows every row so the figure can be defended.

### Does a double power point count as one or two points?

Two. Note 8 to Table C1 treats a multiple combination socket-outlet as the same number of points as it has integral socket-outlets, so a double is two points in group (b)(i). Each permanently connected appliance not exceeding 10 A (a rangehood, an exhaust fan, a garage door motor) is one more point under Note 9, and a 15 A or 20 A socket-outlet adds a flat 10 A or 15 A to the group (b) base loading once, under Note 10.

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

Yes, through limitation. Clause 2.2.2(d) lets the maximum demand be determined by the current rating of a fixed circuit-breaker or the load setting of an adjustable one, and a load management system that holds the current below a set value behind that device gives the same result: the demand is the setting, not the sum of the nameplates behind it. The setting must be fixed and documented, the cable and the device must still be rated for it, and the distributor may require it to be shown on the drawings. It is the only route to diversity for EV chargers in a house or a non-domestic installation.

## Related ElecAS pages

- [Solar Voltage Rise Calculator](https://elecas.com.au/calculator/voltage-rise)
- [Table C1 Calculator](https://elecas.com.au/calculator/c1)
- [Table C2 Calculator](https://elecas.com.au/calculator/c2)
- [Table C3 Calculator](https://elecas.com.au/calculator/c3)
- [Cable Selection](https://elecas.com.au/calculator/cable-selection)
- [Switchboard Sizing Calculator](https://elecas.com.au/calculator/switchboard-sizing)
- [Lightning Risk Assessment Calculator](https://elecas.com.au/calculator/lightning-risk)
- [EleCAD Single Line Diagram Builder](https://elecas.com.au/elecad)
- [Design Guides](https://elecas.com.au/design-guide)
- [AI Mode](https://elecas.com.au/ai)

## About this page

Written and reviewed by Wisam Tozah, Associate Electrical Engineer (B.Eng (Electrical), MIEAust, CPEng, NER, NSW DBP, NSW PRE, APEC, IntPE(Aus)), Sydney, Australia. How the calculations are tested and reviewed: https://elecas.com.au/verification. Profile: https://elecas.com.au/creator.

Usage: this page may be read, indexed, retrieved and cited, including as grounding for an AI answer, with attribution to ElecAS and a link to https://elecas.com.au/calculator/max-demand. Reproducing it, training a model on it, or using it to build a derivative or competing site is not licensed. Terms: https://elecas.com.au/terms. Machine-readable policy: https://elecas.com.au/ai-usage-policy.json

Site index for assistants: https://elecas.com.au/llms.txt — full content: https://elecas.com.au/llms-full.txt