---
title: "Table C2 Maximum Demand Calculator: Non-Domestic Installations to AS/NZS 3000:2018"
url: "https://scaleset.com.au/calculator/c2"
description: "Free AS/NZS 3000 Table C2 maximum demand calculator for offices, shops, factories, schools, hotels and hospitals: all ten load groups, both columns."
updated: "2026-10-13"
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 C2 (Maximum demand: non-domestic electrical installations, load groups (a) to (j), Columns 2 and 3)"
  - "AS/NZS 3000:2018 Appendix C Paragraph C2.5.2 (assessment of welding machines, taking power factor correction into account)"
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."
---

# Table C2 Maximum Demand Calculator: Non-Domestic Installations to AS/NZS 3000:2018

Source: https://scaleset.com.au/calculator/c2

Free, browser-based maximum demand calculator implementing AS/NZS 3000:2018 Appendix C Table C2: the deemed-to-comply method for non-domestic electrical installations. It implements all ten AS/NZS 3000 Table C2 load groups: (a) lighting, (b) socket-outlets split into those not exceeding 10 A, those in buildings with permanently installed heating or cooling, and those exceeding 10 A, (c) appliances for cooking, heating and cooling including instantaneous water heaters plus electric vehicle charging equipment, (d) motors, (e) lifts, (f) fuel dispensing units, (g) heating elements for thermal storage, water heating, pools, spas and saunas, (h) welding machines, listed one by one and assessed under AS/NZS 3000 Paragraph C2.5.2, (i) X-ray equipment and (j) other equipment by assessment. Both published columns are supported and are selected by occupancy: 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. The highest-plus-remainder groups take a list of items and identify the highest-rated one for you: socket-outlets over 10 A and cooking, heating and cooling appliances at full rating plus 50% (Column 2) or 75% (Column 3) of the remainder, EV chargers at full rating plus 75% of the remainder in both columns, motors at full load of the largest plus 50% of the remainder or, in Column 3, plus 75% of the second largest and 50% of the rest, and lifts at 125% of the largest lift motor plus 75% of the next plus 50% of the remainder. The result is a demand in amperes per phase with a line-by-line breakdown naming each group and the expression applied, exportable as a PDF report (downloading it needs a free account; your own logo and accent colour on it are Pro).

The ScaleSet AS/NZS 3000 Table C2 Calculator computes the maximum demand of a non-domestic electrical installation under AS/NZS 3000:2018 Appendix C Table C2, in amperes per phase, for sizing consumer mains and submains. It implements load groups (a) to (j) across both occupancy columns: Column 2 for residential institutions, hotels, hospitals and motels, Column 3 for factories, shops, offices, schools and churches. It is a free browser-based engineering tool and is distinct from the AS/NZS 3000 Table C3 energy demand method, which assesses the same class of installation from floor area in VA/m² instead of from an itemised load schedule.

## Key facts

- AS/NZS 3000 Table C2 has two demand columns chosen by occupancy: Column 2 for residential institutions, hotels, boarding houses, hospitals, accommodation houses and motels; Column 3 for factories, shops, stores, offices, business premises, schools and churches.
- The load groups are (a) lighting, (b) socket-outlets, (c) appliances for cooking, heating and cooling plus EV charging equipment, (d) motors, (e) lifts, (f) fuel dispensing units, (g) thermal storage and pool, spa and sauna heating elements, (h) welding machines, (i) X-ray equipment and (j) other equipment by assessment.
- Lighting is assessed at 75% of connected load in Column 2 and at full connected load in Column 3.
- Most groups use a highest-plus-remainder form: socket-outlets over 10 A and cooking, heating and cooling appliances take the full rating of the highest-rated item plus 50% (Column 2) or 75% (Column 3) of the remainder.
- Lifts are group (e), separate from motors in group (d): 125% of the largest lift motor, plus 75% of the next largest, plus 50% of the remaining lift motors, in both columns.
- EV charging equipment is group (c)(ii): the full connected load of the highest-rated unit plus 75% of the remainder, in both columns.
- Motors and lifts are assessed on full-load current. A motor's nameplate kW is its shaft output, so its electrical input is that figure divided by the efficiency; a lift's full-load current is the current lifting maximum rated load at maximum rated speed.

## Who this page is for

Electrical engineers, building services designers, estimators and contractors sizing consumer mains and submains for offices, retail, warehouses, factories, schools, churches, hotels, motels and hospitals in Australia and New Zealand, and anyone assessing the communal lift and motor loads that AS/NZS 3000 Table C1 refers back to AS/NZS 3000 Table C2.

## 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 C2 (Maximum demand: non-domestic electrical installations, load groups (a) to (j), Columns 2 and 3)
- AS/NZS 3000:2018 Appendix C Paragraph C2.5.2 (assessment of welding machines, taking power factor correction into account)

## What this tool does

- Implements all ten AS/NZS 3000:2018 Table C2 load groups: (a) lighting, (b) socket-outlets, (c) cooking, heating and cooling appliances plus EV charging equipment, (d) motors, (e) lifts, (f) fuel dispensing units, (g) thermal storage, pool, spa and sauna heating elements, (h) welding machines, (i) X-ray equipment and (j) other equipment by assessment.
- Supports both published 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. The two descriptions the table itself uses, so the column choice is unambiguous.
- Assesses lighting at 75% of connected load in Column 2 and full connected load in Column 3, and socket-outlets not exceeding 10 A at 1000 W for the first outlet plus 400 W (Column 2) or 750 W (Column 3) each additional: or 1000 W plus 100 W each additional where the building has permanently installed heating or cooling.
- Ranks multi-item groups automatically so the highest-rated item is identified: socket-outlets over 10 A and cooking, heating and cooling appliances at full rating plus 50% or 75% of the remainder, and EV charging equipment at full rating plus 75% of the remainder in both columns.
- Keeps lifts in their own group (e) rather than lumping them with motors (125% of the largest lift motor, plus 75% of the next largest, plus 50% of the remaining lift motors), which is the grouping error that most often undersizes a commercial consumer mains.
- Covers the specialist groups other calculators skip: fuel dispensing units (first motor at full load, second at 50%, additional at 25%, lighting at full load), thermal storage and pool, spa and sauna heating elements at full-load current, welding machines listed one by one and assessed under AS/NZS 3000 Paragraph C2.5.2 (arc welders 100, 100, 85, 70 then 60%; resistance welders by operation or duty cycle, the largest in full and the rest at 60%), and X-ray equipment at 50% of the largest unit with additional units ignored.
- Shows a line-by-line breakdown giving each group, its input, the expression applied ("Highest 100% + Rest 75%", "1st 125% + 2nd 75% + Rest 50%") and its contribution in amperes, with optional overall diversity and spare capacity added as their own lines.
- Exports a PDF maximum demand report with full project metadata, ready for the design submission and compliance record (downloading it needs a free account; your own logo and accent colour on it are Pro).
- 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 C2

1. **Pick the AS/NZS 3000 Table C2 column for the occupancy** — Choose Column 2 (residential institutions, hotels, boarding houses, hospitals, accommodation houses and motels), or Column 3: factories, shops, stores, offices, business premises, schools and churches. The column sets the diversity factors for lighting, socket-outlets, appliances and motors.
2. **Set the phases and power factor** — Select single-phase (230 V) or three-phase (400 V) consumer mains and enter the project power factor. Connected loads are entered in watts and converted to amperes per phase.
3. **Sort the connected loads into the AS/NZS 3000 Table C2 groups** — Group (a) lighting; (b) socket-outlets, split into ≤10 A, ≤10 A in buildings with permanent heating or cooling, and >10 A; (c) cooking, heating and cooling appliances plus EV charging equipment; (d) motors; (e) lifts; (f) fuel dispensing units; (g) thermal storage, pool, spa and sauna heating elements; (h) welding machines; (i) X-ray equipment; (j) everything else by assessment.
4. **Enter each item at its connected load** — For the highest-plus-remainder groups, add each appliance, motor, lift or charger as its own item at full connected load. The calculator ranks them and applies the full rating to the highest and the group factor to the remainder: do not pre-diversify the inputs.
5. **Add any overall diversity and spare capacity** — Apply a project diversity factor or a spare-capacity percentage only where the design brief requires them. Both are applied after the AS/NZS 3000 Table C2 groups and appear as separate lines so the AS/NZS 3000 Appendix C figure stays visible.
6. **Review the breakdown and export the report** — Check each group's contribution and the expression used against your load schedule, then export the PDF report for the design submission (a free account to download).

## AS/NZS 3000:2018 Table C2: maximum demand for non-domestic installations

### What AS/NZS 3000 Table C2 covers

AS/NZS 3000:2018 Appendix C Table C2 ("Maximum demand: non-domestic electrical installations") is the deemed-to-comply calculation method for consumer mains and submains serving any installation that is not a dwelling: offices, retail, factories, warehouses, schools, hospitals, hotels and motels, along with the communal lift and motor loads that AS/NZS 3000 Table C1 refers back to Table C2 for.

The table has three columns. Column 1 names the load group. Column 2 gives the assessment for residential institutions, hotels, boarding houses, hospitals, accommodation houses and motels. Column 3 gives the assessment for factories, shops, stores, offices, business premises, schools and churches. The ScaleSet Table C2 calculator asks for the building type using those two descriptions verbatim, so there is no ambiguity about which column your project falls in.

### The ten load groups and their expressions

Group (a) lighting, other than the lighting inside a fuel dispensing unit, which sits in group (f), is assessed at 75% of connected load in Column 2 and at full connected load in Column 3.

Group (b) covers socket-outlets in three parts. Outlets not exceeding 10 A are assessed as 1000 W for the first outlet plus 400 W (Column 2) or 750 W (Column 3) for each additional outlet. Where the building has permanently installed heating or cooling equipment, that becomes 1000 W for the first outlet plus 100 W for each additional outlet in both columns. Socket-outlets exceeding 10 A take the full current rating of the highest-rated outlet, plus 50% (Column 2) or 75% (Column 3) of the full rating of the remainder.

Group (c)(i) covers appliances for cooking, heating and cooling including instantaneous water heaters: full connected load of the highest-rated appliance plus 50% (Column 2) or 75% (Column 3) of the remainder. Group (c)(ii) covers charging equipment associated with electric vehicles: full connected load of the highest-rated unit plus 75% of the remainder, in both columns.

Group (d) motors take the full load of the highest-rated motor plus 50% of the remainder in Column 2; Column 3 takes the full load of the highest-rated motor, plus 75% of the second highest, plus 50% of the remainder. Group (e) lifts are assessed identically in both columns as 125% of the largest lift motor, plus 75% of the next largest, plus 50% of the remaining lift motors, where the full-load current means the current drawn lifting maximum rated load at maximum rated speed.

Group (f) fuel dispensing units take the first motor at full load, the second at 50%, additional motors at 25%, and their lighting at full connected load. Group (g) (heating elements associated with thermal storage heaters, water heaters, space heaters, swimming pools, spas and saunas) takes full-load current. Group (h) welding machines are assessed under AS/NZS 3000 Paragraph C2.5.2, from each machine’s primary current, the marked corrected figure where power factor correction is fitted. Group (i) X-ray equipment takes 50% of the full load of the largest unit, with additional units ignored. Group (j) is everything else, by assessment.

### Where AS/NZS 3000 Table C2 assessments go wrong

The most frequent grouping error is putting a lift in group (d) with the other motors. Lifts are group (e) and carry a 125% factor on the largest machine to cover starting current: assessing a lift as an ordinary motor understates the demand. Conversely, a kitchen exhaust fan or a pump is an ordinary motor in group (d), not a lift.

The second is entering an already-diversified figure. Every AS/NZS 3000 Table C2 expression takes connected load and applies the diversity itself, so entering a "design load" that has had a factor applied to it diversifies the same load twice and undersizes the mains.

The third is column choice. A hotel and an office are both non-domestic, but a hotel is a Column 2 occupancy and an office is a Column 3 occupancy, and Column 3 is the more onerous assessment for lighting (full connected load rather than 75%) and for the remainder terms in groups (b)(i), (b)(iii), (c)(i) and (d).

The fourth is entering a motor's nameplate kW. That is the power at the shaft, and the current AS/NZS 3000 Table C2 assesses is drawn at the input, which is higher by the motor's efficiency. Enter the electrical input in watts: the nameplate kW divided by the efficiency, or √3 × 400 V × the full-load current × the power factor for a three-phase motor.

### What the calculator does

The ScaleSet Table C2 calculator implements all ten load groups with the published Column 2 and Column 3 expressions. Each group can be switched on or off, multi-item groups (socket-outlets over 10 A, appliances, EV chargers, motors, lifts, welding machines, X-ray units) accept a list of items and sort them internally so the highest-rated item is identified for you, and the breakdown records the expression applied to each group: "Highest 100% + Rest 75%", "1st 125% + 2nd 75% + Rest 50%" and so on.

Loads are entered in watts with a project power factor, and converted at 230 V single-phase or 400 V three-phase to give the demand in amperes per phase. On three phases every load is taken as balanced over the phases; a single-phase load draws its full 230 V current on one phase, so where the large loads are single-phase, assess each phase on its own and take the heaviest. An optional overall diversity factor and a spare-capacity percentage can be applied on top of the AS/NZS 3000 Table C2 result where the design brief calls for them, and both are shown as separate lines in the breakdown and the exported PDF report rather than being folded silently into the total.

Where the installation type is one of the occupancies tabulated in AS/NZS 3000 Table C3 and the design is still at the floor-area stage, the Table C3 energy demand method is the faster route: see the Table C3 calculator.

## Key terms

- **AS/NZS 3000 Table C2** — The AS/NZS 3000:2018 Appendix C table giving the deemed-to-comply maximum demand method for non-domestic installations, assessed by itemising equipment into ten load groups.
- **Column 2 (AS/NZS 3000 Table C2)** — The assessment column for residential institutions, hotels, boarding houses, hospitals, accommodation houses and motels: occupancies where people sleep.
- **Column 3 (AS/NZS 3000 Table C2)** — The assessment column for factories, shops, stores, offices, business premises, schools and churches: occupancies used during working hours.
- **Highest-plus-remainder** — The pattern several AS/NZS 3000 Table C2 groups use: take the full rating of the highest-rated item, then a stated percentage of everything else in the group. It reflects that the largest item is the one most likely to run at full load.
- **Connected load** — The sum of the nameplate ratings of all equipment, before any diversity is applied. Maximum demand is almost always lower, because AS/NZS 3000 Appendix C assumes not everything runs at once.
- **Non-domestic installation** — An installation that is not a dwelling. Where equipment can be itemised, AS/NZS 3000 Table C2 applies; where only floor areas are known at early design, AS/NZS 3000 Table C3 is used instead.

## Frequently asked questions

### Which AS/NZS 3000 Table C2 column applies to my building?

AS/NZS 3000 Table C2 has two demand columns chosen by occupancy. Column 2 covers residential institutions, hotels, boarding houses, hospitals, accommodation houses and motels. Column 3 covers factories, shops, stores, offices, business premises, schools and churches. Column 3 is the harder assessment: lighting goes to full connected load instead of 75%, general 10 A outlets go from 400 W to 750 W each after the first, and the leftover items in the socket-outlets-over-10 A and appliance groups count at 75% instead of 50%. Motors are the odd one out: in Column 3 the second-biggest motor counts at 75%, but everything after it still counts at 50%, same as Column 2.

### How does AS/NZS 3000 Table C2 apply diversity?

Diversity sits inside each load group, not in one factor at the end. Lighting is a straight percentage of connected load. General 10 A outlets use a watts-for-the-first-outlet plus watts-for-each-extra allowance. Socket-outlets over 10 A, appliances and EV chargers count the biggest item in full and the rest at a reduced percentage. Motors add a middle step in Column 3: biggest in full, second at 75%, the rest at 50%. Lifts are their own rule again: the largest lift motor at 125%, the next at 75% and the rest at 50%, where a lift motor's full-load current is the current it takes lifting its maximum rated load at maximum rated speed. Because the table does the diversity for you, always enter connected loads, never a figure you have already discounted.

### What is the difference between Table C1 and Table C2 in AS/NZS 3000?

AS/NZS 3000 Table C1 covers single and multiple domestic installations, and selects its assessment column from the number of living units per phase. AS/NZS 3000 Table C2 covers non-domestic installations and selects 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. A mixed-use building uses AS/NZS 3000 Table C1 for the dwellings and Table C2 for the non-residential portions, summed at the main switchboard.

### Which loads belong in each AS/NZS 3000 Table C2 group?

Group (a) lighting; group (b) socket-outlets (≤10 A, ≤10 A in buildings with permanent heating or cooling, and >10 A); group (c) appliances for cooking, heating and cooling including instantaneous water heaters, plus EV charging equipment; group (d) motors; group (e) lifts; group (f) fuel dispensing units; group (g) heating elements for thermal storage, pools, spas and saunas; group (h) welding machines; group (i) X-ray equipment; group (j) other equipment by assessment. The ScaleSet calculator labels every input with its AS/NZS 3000 Appendix C group letter.

### Are lifts assessed as motors under AS/NZS 3000 Table C2?

No. Lifts are their own load group (e) and are assessed at 125% of the largest lift motor, plus 75% of the next largest, plus 50% of the remaining lift motors, in both columns. Ordinary motors (fans, pumps, compressors) are group (d), which uses full load of the highest-rated motor plus 50% of the remainder in Column 2, or plus 75% of the second highest and 50% of the remainder in Column 3.

### How do I calculate maximum demand for an office?

Use AS/NZS 3000 Table C2 Column 3, which covers offices, shops, factories and other business premises, including a single office tenancy. Lighting (a) is full connected load. General socket-outlets up to 10 A are 1000 W for the first plus 750 W for each additional (b)(i), or 1000 W plus 100 W each where the area has permanently installed heating or cooling that makes portable heaters unnecessary ((b)(ii) and Note 4), which covers most air-conditioned offices. Air conditioning and other appliances (c)(i) take the highest-rated item in full plus 75% of the rest, motors (d) the largest in full plus 75% of the second plus 50% of the rest, and lifts (e) 125%, 75% and 50%. At concept stage, before the loads are known, the AS/NZS 3000 Table C3 office density of 50 VA/m² for light and power is the quicker route.

### Does AS/NZS 3000 Table C2 cover EV charging stations?

Yes. Charging equipment associated with electric vehicles is load group (c)(ii) of AS/NZS 3000 Table C2, assessed as the full connected load of the highest-rated unit plus 75% of the full load of the remainder, in both Column 2 and Column 3. The ScaleSet calculator keeps EV chargers as their own line so the charging contribution to the consumer mains demand is visible in the report.

### How is welding machine maximum demand calculated under AS/NZS 3000?

AS/NZS 3000 Table C2 group (h) sends welding machines to Paragraph C2.5.2. One arc welder is 100% of its rated primary current; a group is the two largest at 100%, the next at 85%, the next at 70% and every other machine at 60%. A resistance welder in varying operation is 70% of its rated primary current if it is a seam or automatically fed machine and 50% if manually operated; one run at a known duty cycle is its actual primary current times the duty-cycle multiplier (0.45 at 20%, 0.71 at 50%). A group of resistance welders is the largest in full plus 60% of the others. Where power factor correction is fitted, the rated primary current is the marked corrected value. The Table C2 calculator takes each machine’s type and primary current and applies these rules for group (h); a figure worked by hand can be added as well.

## Related ScaleSet pages

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## About this page

Methods built and reviewed by Wisam Tozah (CPEng, NER, MIEAust), Sydney, Australia. How the methods are tested and reviewed: https://scaleset.com.au/verification. ScaleSet is a design aid: your inputs and results are not reviewed or certified, and responsibility for the design stays with the engineer who issues it. Profile: https://scaleset.com.au/creator.

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