What is AS/NZS 3000 Table C1 used for?

Table C1 in AS/NZS 3000:2018 provides the maximum demand calculation method for single-domestic and multi-domestic electrical installations, covering loads such as lighting, socket outlets, cooking, hot water, air conditioning and EV charging.

How is maximum demand calculated for a single dwelling?

For a single dwelling, sum the assessed demand for each load group in Table C1 (Column 1 for the first 20 A then Column 2 for the remainder), accounting for cooking appliances, water heaters, fixed space heating, motor loads, EV charging and socket outlets, then apply diversity per the table notes.

Does Table C1 include EV charging?

Yes. AS/NZS 3000:2018 Amendment 2 added explicit treatment of EV supply equipment in domestic installations. The ElecAS Table C1 calculator includes an EV charging input that follows the assessed demand rules.

What is the difference between Table C1 and Table C2?

Table C1 applies to domestic installations (single dwellings and multi-unit residential), while Table C2 applies to non-domestic installations such as offices, retail, industrial and hospitality. Use C3 (energy demand method) for floor-area-based assessments.

Does Table C1 apply to a single house?

Yes. Table C1 covers single dwellings as well as multiple-dwelling installations. For a single dwelling the dwelling-count band is "1" and the per-row expressions evaluate accordingly. The AS/NZS 3000 Clause 2.2.2 minimum of 32 A applies as a floor.

When do I use Table C1 vs Table C2 for a mixed-use building?

Use Table C1 for the residential submains and Table C2 for non-residential common services (lift, lobby lighting, ventilation, retail tenancy). Add the results at the main switchboard. If common services demand exceeds 10% of dwellings demand, the entire installation is treated under Table C2.

How do EV chargers affect a Table C1 calculation?

EV chargers are handled under AS/NZS 3000:2018 Clause 2.2.2(c). For one or two chargers in a single dwelling the full charger demand is added to the Table C1 result without diversity. For a multiple-dwelling installation with a primary load-management system that limits simultaneous charging, the calculated demand may recognise that limit — refer to the Electric Vehicle Council guidance on load control for the dwelling context.

Does PV reduce my Table C1 maximum demand?

No. The consumer mains must be sized to carry full grid-import current if the PV inverter trips. PV generation is not subtracted from the Table C1 result for cable sizing purposes under AS/NZS 3000.

ElecAS

Table C1 Domestic Maximum Demand Calculator

Calculate domestic maximum demand for dwellings and multi-unit scenarios using AS/NZS 3000 Table C1 logic.

Why this page matters

Calculate domestic maximum demand for dwellings and multi-unit scenarios using AS/NZS 3000 Table C1 logic. This static content is published so the canonical route has meaningful crawlable HTML even before the interactive application hydrates.

Who this page is for

Residential designers, electricians and consultants sizing domestic main supplies and consumer mains.

Relevant standards

AS/NZS 3000 Table C1

What this tool helps with

Estimate domestic maximum demand for single dwellings and multi-unit arrangements.
Include common residential loads such as cooking, hot water, air conditioning and EV charging.
Review demand outcomes before moving into cable sizing or voltage-drop checks.

How to calculate maximum demand using AS/NZS 3000 Table C1

Set the number of dwellings — Enter 1 for a single dwelling or the actual count for a multiple-dwelling installation. The dwelling-count band (1, 2, 3–5, 6–20, 21–40, 41+) determines which column of Table C1 applies.
Enter the connected loads per dwelling — Enter the installed lighting wattage, the number and rating of cooking appliances, water heater type and rating, spa or pool heating, fixed A/C kW, EV charger kW, and any other Appendix C row that applies.
Confirm the supply phase configuration — Pick single-phase or three-phase consumer mains. For three-phase the per-row currents are divided per phase as Table C1 specifies (some rows are single-phase loads even on a three-phase mains).
Review the per-row contribution — The calculator shows the contribution of each Table C1 row to the total maximum demand, the dwelling-count band used and any applied 32 A Clause 2.2.2 floor.
Export the branded PDF — The PDF lists every row applied with its Table C1 reference and the calculation expression, suitable for inclusion in a design submission package.

AS/NZS 3000:2018 Table C1 — maximum demand for single and multiple dwellings

What Table C1 covers

AS/NZS 3000:2018 Appendix C Table C1 specifies the maximum demand calculation method for consumer mains and submains serving single dwellings (houses, single units) and multiple-dwelling installations (unit blocks, townhouses, apartments) where the common services demand is less than 10% of the dwellings demand. The table is divided into rows by load type and columns by dwelling-count band: 1, 2, 3–5, 6–20, 21–40 and 41+.

For each row the expression evaluates to a current in amperes per phase that contributes to the consumer mains or submain demand. Rows include general light and power, range / cooktop, water heater (storage, instantaneous and heat-pump), spa / pool heating, fixed and portable A/C, EV chargers (handled under Clause 2.2.2(c)), instantaneous water heating, and motors.

How dwelling-count diversity works

Diversity in Table C1 is captured implicitly in the per-row expressions. For example, general light and power for a single dwelling contributes 3 A per 1000 W of installed lighting + a per-dwelling current for socket-outlet load. For a 21-dwelling block the per-dwelling contribution is reduced because not all 21 dwellings draw their full load simultaneously.

The expressions are NOT the same as a single diversity factor applied across all loads — each load type has its own diversity profile. Cooking peaks differ from heating peaks differ from EV charging peaks, and the table captures this with row-specific expressions.

Common Table C1 compliance traps

The most frequent compliance issue is mixing Table C1 (per-dwelling) and Table C2 (non-domestic) loads on the same submain — common-services loads (lift, lobby lighting, ventilation) for a unit block must be treated under Table C2 and added to the Table C1 dwellings demand at the main switchboard. The 10% threshold in Clause C2 determines whether common services dominates.

Another trap is the AS/NZS 3000 Clause 2.2.2 minimum current floor — single-dwelling consumer mains have a 32 A minimum regardless of calculated demand. The ElecAS C1 calculator applies the floor automatically and shows both the raw calculated demand and the post-floor demand.

Reviewed by

Wisam Tozah — Associate Electrical Engineer. B.Eng (Electrical), MIEAust, CPEng, NER, NSW DBP, NSW PRE, APEC, IntPE(Aus). LinkedIn.

Frequently asked questions

What is AS/NZS 3000 Table C1 used for?: Table C1 in AS/NZS 3000:2018 provides the maximum demand calculation method for single-domestic and multi-domestic electrical installations, covering loads such as lighting, socket outlets, cooking, hot water, air conditioning and EV charging.
How is maximum demand calculated for a single dwelling?: For a single dwelling, sum the assessed demand for each load group in Table C1 (Column 1 for the first 20 A then Column 2 for the remainder), accounting for cooking appliances, water heaters, fixed space heating, motor loads, EV charging and socket outlets, then apply diversity per the table notes.
Does Table C1 include EV charging?: Yes. AS/NZS 3000:2018 Amendment 2 added explicit treatment of EV supply equipment in domestic installations. The ElecAS Table C1 calculator includes an EV charging input that follows the assessed demand rules.
What is the difference between Table C1 and Table C2?: Table C1 applies to domestic installations (single dwellings and multi-unit residential), while Table C2 applies to non-domestic installations such as offices, retail, industrial and hospitality. Use C3 (energy demand method) for floor-area-based assessments.
Does Table C1 apply to a single house?: Yes. Table C1 covers single dwellings as well as multiple-dwelling installations. For a single dwelling the dwelling-count band is "1" and the per-row expressions evaluate accordingly. The AS/NZS 3000 Clause 2.2.2 minimum of 32 A applies as a floor.
When do I use Table C1 vs Table C2 for a mixed-use building?: Use Table C1 for the residential submains and Table C2 for non-residential common services (lift, lobby lighting, ventilation, retail tenancy). Add the results at the main switchboard. If common services demand exceeds 10% of dwellings demand, the entire installation is treated under Table C2.
How do EV chargers affect a Table C1 calculation?: EV chargers are handled under AS/NZS 3000:2018 Clause 2.2.2(c). For one or two chargers in a single dwelling the full charger demand is added to the Table C1 result without diversity. For a multiple-dwelling installation with a primary load-management system that limits simultaneous charging, the calculated demand may recognise that limit — refer to the Electric Vehicle Council guidance on load control for the dwelling context.
Does PV reduce my Table C1 maximum demand?: No. The consumer mains must be sized to carry full grid-import current if the PV inverter trips. PV generation is not subtracted from the Table C1 result for cable sizing purposes under AS/NZS 3000.