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.

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.

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.

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Maximum Demand Calculators

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.

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 helps with

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

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.
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.
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.
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.
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.
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.
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.

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.

Reviewed by

Wisam Tozah: Associate Electrical Engineer. B.Eng (Electrical), MIEAust, CPEng, NER, NSW DBP, NSW PRE, APEC, IntPE(Aus). See how these calculations are verified. LinkedIn.

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.
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.