What is AS/NZS 3000 Table C1 used for?

Table C1 of AS/NZS 3000:2018 Appendix C is the tabulated method for calculating the maximum demand of single and multiple domestic electrical installations (a house, an individual unit, or a block of living units), so consumer mains and submains can be sized. It covers lighting, socket-outlets, cooking and laundry, fixed heating and air conditioning, instantaneous and storage water heating, spa and pool heating, and the communal lighting, appliances, EV charging, lifts and motors that serve a block.

How is maximum demand calculated for a single dwelling under Table C1?

A single dwelling is assessed under Column 2, one load group at a time, and the group results are added up to give the demand in amps per phase. Lighting is 3 A for the first 20 points plus 2 A for each extra 20 or part of 20. Socket-outlets up to 10 A are 10 A for the first 20 points plus 5 A for each extra 20. Add 10 A if the installation has any 15 A outlets, and add 15 A if it has any 20 A outlets: where both are present the calculator applies the higher 15 A allowance only, so check that against your reviewer's reading of rows (b)(ii) and (b)(iii). Ranges, cooking and laundry count at 50% of connected load, fixed space heating and air conditioning at 75%, instantaneous water heaters at 33.3% and storage water heaters at full load. Spa and pool heating is 75% of the largest spa, plus 75% of the largest pool, plus 25% of the rest.

What is the difference between Table C1 and Table C2?

Table C1 covers domestic installations and reads its assessment column from the number of living units per phase. Table C2 covers non-domestic installations and reads its column from the occupancy type: Column 2 for hotels, hospitals, motels and similar residential institutions, Column 3 for factories, shops, offices, schools and churches. Table C3 is the third route: an energy demand method that assesses a non-domestic installation from floor area in VA/m².

Does Table C1 apply to a single house?

Yes. Column 2 of Table C1 is headed "Single domestic electrical installation or individual living unit per phase", so it is the correct assessment for a single house as well as for an individual unit. AS/NZS 3000 itself does not set a minimum consumer mains current; minimum sizes come from the local distributor's service and installation rules.

Which Table C1 column applies to a block of units?

The column is selected by the number of living units on the heaviest phase, not the total number of units. Column 3 covers 2 to 5 living units per phase, Column 4 covers 6 to 20, and Column 5 covers 21 or more. A 20-unit block on a three-phase supply has 7 units per phase, so Column 4 applies.

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

Use Table C1 for the dwellings and their communal loads, and Table C2 (or the Table C3 energy demand method) for the non-domestic portion (retail tenancies, offices or commercial common areas) then add the results at the main switchboard. The ElecAS C1 calculator also accepts a non-domestic area in VA/m² so a mixed-use consumer mains can be assessed in one calculation.

How do EV chargers affect a Table C1 calculation?

EV charging equipment is load group (j)(iv) of Table C1. A single domestic electrical installation takes the full connected load. Blocks of living units take 100% of connected load for 2 to 5 units per phase, 90% for 6 to 20, and 75% for 21 or more. The ElecAS calculator also offers the NCC load-allowance method as an alternative, which assesses charging spaces by building class.

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 or the array is not generating, so PV output is not subtracted from the Table C1 result for cable sizing under AS/NZS 3000.

ElecAS

Table C1 Maximum Demand Calculator: Single and Multiple Domestic Installations to AS/NZS 3000:2018

Free, browser-based maximum demand calculator implementing AS/NZS 3000:2018 Appendix C Table C1: the deemed-to-comply method for single domestic electrical installations and blocks of living units. It works through all thirteen Table C1 load groups: (a) lighting including outdoor lighting over 1000 W, (b) socket-outlets not exceeding 10 A with the additional allowances for 15 A and 20 A outlets, (c) ranges, cooking appliances and laundry equipment, (d) fixed space heating, air conditioning and saunas, (e) instantaneous water heaters, (f) storage water heaters, (g) spa and swimming pool heaters, and for blocks of units the communal groups (h) lighting, (i) socket-outlets, (j) appliances over 10 A including electric vehicle charging, (k) lifts, (l) motors and (m) other loads over 10 A. The Table C1 assessment column is selected automatically from the 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), because the table is read per phase, not per development. EV charging can be assessed under Table C1 group (j)(iv) (full connected load for a single dwelling, then 100%, 90% or 75% by column) or under the NCC load-allowance method by building class. Mixed-use developments can add a non-domestic portion by floor area in VA/m². The result is a demand in amperes per phase with a line-by-line breakdown showing every load group, its input, the expression applied and its contribution, exportable as a branded PDF report for the design submission.

Key facts

Table C1 has four demand columns, chosen by the number of living units ON THE HEAVIEST PHASE: Column 2 (a single domestic installation, or one living unit per phase), Column 3 (2 to 5 units per phase), Column 4 (6 to 20 units per phase) and Column 5 (21 or more units per phase).
Living units per phase = total units ÷ number of phases, rounded up. Twenty units across three phases is 7 units per phase, so Column 4 applies: not Column 5.
Every load group (a) to (m) carries its own diversity expression. There is no single blanket diversity factor in Table C1.
Column 2 assesses lighting at 3 A for the first 1–20 points plus 2 A per additional 20 points, socket-outlets at 10 A for the first 1–20 points plus 5 A per additional 20 points, cooking and laundry at 50% of connected load, fixed heating or air conditioning at 75%, instantaneous water heaters at 33.3% and storage water heaters at full load current.
EV charging sits in load group (j)(iv): full connected load for a single domestic installation, then 100% (Column 3), 90% (Column 4) and 75% (Column 5) of connected load.

Who this page is for

Electrical engineers, designers, estimators and licensed electricians sizing consumer mains and submains for houses, duplexes, townhouses, apartment blocks and mixed-use residential developments in Australia and New Zealand, and apprentices learning the AS/NZS 3000 Appendix C maximum demand method.

Relevant standards

AS/NZS 3000:2018 (Wiring Rules: Clause 2.2.2 determination of maximum demand by calculation, assessment, measurement or limitation)
AS/NZS 3000:2018 Appendix C Table C1 (Maximum demand: single and multiple domestic electrical installations, load groups (a) to (m), Columns 2 to 5)
AS/NZS 3000:2018 Appendix C Paragraph C2.4.1 and Table C2 (assessment of lift motors referenced from Table C1 load group (k))
National Construction Code (NCC) electric vehicle charging load allowances, offered as an alternative EV assessment method

What this tool helps with

Implements all thirteen AS/NZS 3000:2018 Table C1 load groups: (a) lighting, (b) socket-outlets, (c) ranges, cooking and laundry, (d) fixed heating, air conditioning and saunas, (e) instantaneous water heaters, (f) storage water heaters, (g) spa and pool heaters, (h) to (j) communal lighting, socket-outlets and appliances, (k) lifts, (l) motors and (m) other loads over 10 A.
Selects the Table C1 assessment column from the living units on the heaviest phase, not the total unit count (a 20-unit block on three phases is 7 units per phase, so Column 4 applies), and shows the column it used alongside the result.
Applies the Column 2 point-based assessments exactly as published: lighting at 3 A for the first 1 to 20 points plus 2 A per additional 20, socket-outlets at 10 A for the first 1 to 20 points plus 5 A per additional 20, with 10 A added for 15 A outlets or 15 A for 20 A outlets.
Applies the Column 3, 4 and 5 per-unit expressions for blocks of living units: lighting at 6 A, 5 A + 0.25 A per unit or 0.5 A per unit; socket-outlets at 10 A + 5 A, 15 A + 3.75 A or 50 A + 1.9 A per unit; cooking at a fixed 15 A or 2.8 A per unit.
Assesses electric vehicle charging under Table C1 group (j)(iv) (full connected load for a single domestic installation, then 100%, 90% or 75% of connected load by column), or under the NCC load-allowance method by building class (Class 2, Classes 5 and 6, Class 3, and Classes 7b, 8 and 9).
Handles fully electrified, gas-cooking and gas-hot-water dwellings, induction cooktop banding, and per-unit or whole-of-site entry for heating, water heating and spa and pool loads.
Adds a non-domestic portion by floor area in VA/m² so a mixed-use consumer mains can be assessed in one calculation, with communal loads listed separately from the dwellings demand.
Shows a line-by-line breakdown giving each load group, its input value, the expression applied and its contribution in amperes, plus optional overall diversity and spare capacity as their own lines so the raw Appendix C figure stays visible.
Exports a branded PDF maximum demand report with full project metadata, ready for the design submission and compliance record.
Built and reviewed by a Chartered Professional Engineer (CPEng, NER, NSW DBP, NSW PRE, APEC, IntPE Aus): see the Verification page for the testing and review process.

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

Enter the number of living units and the phase configuration: Enter 1 for a single dwelling, or the actual unit count for a block. Set single-phase or three-phase. The calculator divides the units across the phases and rounds up to get the living units per phase, which is what selects the Table C1 column (Column 2, 3, 4 or 5).
Turn on the load groups that apply: Enable the Table C1 load groups present in the installation: (a) lighting, (b) socket-outlets, (c) ranges, cooking and laundry over 10 A, (d) fixed heating and air conditioning, (e) instantaneous water heaters, (f) storage water heaters and (g) spa and pool heaters.
Enter the connected load for each group: Lighting and socket-outlets are entered as point counts; cooking, heating, air conditioning and water heating are entered in watts. Enter the connected load, not an already-diversified figure: the table applies the diversity.
Add communal and non-domestic loads for a block of units: For blocks of living units add the communal groups: (h) communal lighting, (i) communal socket-outlets, (j) communal appliances including EV charging, (k) lifts, (l) motors and (m) other loads over 10 A. Any non-domestic portion can be entered as a floor area with a VA/m² density.
Choose the EV charging assessment method: Select the AS/NZS 3000 Table C1 (j)(iv) assessment (full connected load for a single dwelling, then 100%, 90% or 75% by column), or the NCC method, which assesses charging spaces by building class.
Review the breakdown and check against the distributor rules: The result shows the total demand in amperes per phase, the Table C1 column applied and each load group's contribution with the expression used. Compare the figure against your DNSP's minimum consumer mains requirements before sizing the cable.
Export the branded PDF report: Fill in the project metadata and export the report. It lists every load group applied, its Table C1 reference and the calculation expression, ready for the design submission package.

AS/NZS 3000:2018 Table C1: maximum demand for single and multiple domestic installations

What Table C1 covers

AS/NZS 3000:2018 Appendix C Table C1 ("Maximum demand: single and multiple domestic electrical installations") is the deemed-to-comply calculation method for consumer mains and submains serving a single dwelling (a house or an individual unit) and for blocks of living units: apartments, townhouses and unit developments.

The table is laid out as load groups (a) to (m) down the side and four demand columns across the top. Column 1 names the load group. Column 2 gives the assessment for a single domestic electrical installation or an individual living unit per phase. Columns 3, 4 and 5 give the assessment for blocks of 2 to 5, 6 to 20, and 21 or more living units per phase respectively. Every expression resolves to a current in amperes per phase, and the column total is the maximum demand.

The load groups split into loads associated with individual units ((a) lighting, (b) socket-outlets not exceeding 10 A, (c) ranges, cooking appliances and laundry equipment, (d) fixed space heating, air conditioning and saunas, (e) instantaneous water heaters, (f) storage water heaters, (g) spa and swimming pool heaters), and loading not associated with individual units: (h) communal lighting, (i) communal socket-outlets, (j) communal appliances rated over 10 A including (j)(iv) electric vehicle charging equipment, (k) lifts, (l) motors and (m) other loads over 10 A.

The column is chosen per phase, not per building

The single most common Table C1 error is reading the column off the total number of dwellings. The column headings are explicit: they are living units PER PHASE. A twenty-unit block on a three-phase supply has ceil(20 ÷ 3) = 7 living units on the heaviest phase, so Column 4 (6 to 20 units per phase) applies: not Column 5.

The ElecAS Table C1 calculator derives the units-per-phase figure from the unit count and the phase configuration you enter, then shows which column it selected (for example "Col 4 (6-20 units)") alongside the result, so the column choice is auditable rather than assumed.

How the diversity actually works, group by group

Diversity in Table C1 is built into each row rather than applied as one factor at the end. For a single domestic installation (Column 2), lighting is assessed at 3 A for the first 1 to 20 points plus 2 A for each additional 20 points or part thereof; socket-outlets not exceeding 10 A at 10 A for the first 1 to 20 points plus 5 A for each additional 20 points; ranges, cooking appliances and laundry equipment at 50% of connected load; fixed space heating, air conditioning and saunas at 75% of connected load; instantaneous water heaters at 33.3% of connected load; and storage water heaters at full-load current. An installation that includes one or more 15 A socket-outlets adds 10 A; one that includes 20 A socket-outlets adds 15 A.

The block-of-units columns replace the points-based rows with per-unit currents. Lighting becomes a fixed 6 A (Column 3), 5 A + 0.25 A per living unit (Column 4) or 0.5 A per living unit (Column 5). Socket-outlets become 10 A + 5 A per unit, 15 A + 3.75 A per unit, or 50 A + 1.9 A per unit. Ranges and cooking become a fixed 15 A (Column 3) or 2.8 A per living unit (Columns 4 and 5). Spa and swimming pool heaters are assessed the same way in every column: 75% of the largest spa, plus 75% of the largest swimming pool, plus 25% of the remainder.

Outdoor lighting exceeding a total of 1000 W is a separate row, (a)(ii), assessed at 75% of connected load for a single domestic installation. For blocks of living units Table C1 records no assessment for that row, and the ElecAS calculator applies it only where a single unit sits on the phase.

EV charging, communal loads and the mixed-use case

Electric vehicle charging equipment is load group (j)(iv). For a single domestic electrical installation it is the full connected load; for blocks of living units it is 100% of connected load in Column 3, 90% in Column 4 and 75% in Column 5. The ElecAS calculator offers this AS/NZS 3000 assessment and, as an alternative, the NCC load-allowance method, which assesses charging spaces by building class (Class 2 at 100% × 1.5 kW, Classes 5 and 6 at 10% × 1.5 kW, Class 3 at 20% × 6.0 kW, and Classes 7b, 8 and 9 at 20% × 1.5 kW).

Communal loads on a block of units (communal lighting at full connected load, communal socket-outlets at 2 A per point up to 15 A, communal clothes dryers and water heaters at 50%, communal fixed heating and air conditioning at 75%, lifts under Paragraph C2.4.1 and Table C2, and motors) are assessed against the phase rather than per unit, and the calculator lists them separately in the breakdown so the dwellings demand and the common-services demand stay distinguishable.

Where a development mixes domestic and non-domestic occupancy, the non-domestic portion is assessed under Table C2 or the Table C3 energy demand method and added at the main switchboard. The ElecAS Table C1 calculator includes a non-domestic area input (VA/m² by area) so a mixed-use consumer mains can be assessed in one place.

What the calculator does and does not do

The calculator returns the Appendix C assessed demand in amperes per phase, with a line-by-line breakdown showing the load group, the input value, the expression applied and the resulting current: the same content that goes into the exported PDF report. An optional overall diversity factor and a spare-capacity percentage can be applied on top of the Table C1 result where the design brief calls for them.

It does not impose a minimum consumer mains current. AS/NZS 3000:2018 Clause 2.2.2 sets out the four permitted ways to determine maximum demand (calculation, assessment, measurement and limitation), and does not specify a numeric floor. Minimum consumer mains sizes are set by the local distributor's service and installation rules, so check the calculated result against your DNSP's requirements before selecting the cable.

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

What is AS/NZS 3000 Table C1 used for?: Table C1 of AS/NZS 3000:2018 Appendix C is the tabulated method for calculating the maximum demand of single and multiple domestic electrical installations (a house, an individual unit, or a block of living units), so consumer mains and submains can be sized. It covers lighting, socket-outlets, cooking and laundry, fixed heating and air conditioning, instantaneous and storage water heating, spa and pool heating, and the communal lighting, appliances, EV charging, lifts and motors that serve a block.
How is maximum demand calculated for a single dwelling under Table C1?: A single dwelling is assessed under Column 2, one load group at a time, and the group results are added up to give the demand in amps per phase. Lighting is 3 A for the first 20 points plus 2 A for each extra 20 or part of 20. Socket-outlets up to 10 A are 10 A for the first 20 points plus 5 A for each extra 20. Add 10 A if the installation has any 15 A outlets, and add 15 A if it has any 20 A outlets: where both are present the calculator applies the higher 15 A allowance only, so check that against your reviewer's reading of rows (b)(ii) and (b)(iii). Ranges, cooking and laundry count at 50% of connected load, fixed space heating and air conditioning at 75%, instantaneous water heaters at 33.3% and storage water heaters at full load. Spa and pool heating is 75% of the largest spa, plus 75% of the largest pool, plus 25% of the rest.
What is the difference between Table C1 and Table C2?: Table C1 covers domestic installations and reads its assessment column from the number of living units per phase. Table C2 covers non-domestic installations and reads its column from the occupancy type: Column 2 for hotels, hospitals, motels and similar residential institutions, Column 3 for factories, shops, offices, schools and churches. Table C3 is the third route: an energy demand method that assesses a non-domestic installation from floor area in VA/m².
Does Table C1 apply to a single house?: Yes. Column 2 of Table C1 is headed "Single domestic electrical installation or individual living unit per phase", so it is the correct assessment for a single house as well as for an individual unit. AS/NZS 3000 itself does not set a minimum consumer mains current; minimum sizes come from the local distributor's service and installation rules.
Which Table C1 column applies to a block of units?: The column is selected by the number of living units on the heaviest phase, not the total number of units. Column 3 covers 2 to 5 living units per phase, Column 4 covers 6 to 20, and Column 5 covers 21 or more. A 20-unit block on a three-phase supply has 7 units per phase, so Column 4 applies.
When do I use Table C1 vs Table C2 for a mixed-use building?: Use Table C1 for the dwellings and their communal loads, and Table C2 (or the Table C3 energy demand method) for the non-domestic portion (retail tenancies, offices or commercial common areas) then add the results at the main switchboard. The ElecAS C1 calculator also accepts a non-domestic area in VA/m² so a mixed-use consumer mains can be assessed in one calculation.
How do EV chargers affect a Table C1 calculation?: EV charging equipment is load group (j)(iv) of Table C1. A single domestic electrical installation takes the full connected load. Blocks of living units take 100% of connected load for 2 to 5 units per phase, 90% for 6 to 20, and 75% for 21 or more. The ElecAS calculator also offers the NCC load-allowance method as an alternative, which assesses charging spaces by building class.
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 or the array is not generating, so PV output is not subtracted from the Table C1 result for cable sizing under AS/NZS 3000.