Switchboard circuit chart
Make a board circuit chart and the labels it needs.
Reads AS/NZS 3000:2018. Tables checked 1 Oct 2026.
Try a job 4
Each job fills in example values. Replace them with your values.
- Make a circuit chart for a house boardSix circuits charted by way, with the main switch label.
- Label a board with solarA shop board with the main switchboard and solar main switch labels.
- Chart a sub-board in a workshopWays for single and three-phase circuits on a distribution board.
- Mark a shared neutralTwo lighting circuits on one neutral, named with their ways.
Inputs
Worked example with the default inputs. The live calculator replaces it when the page loads.
- Board name
- Not stated
- Board
- Main switchboard
- Single domestic installation
- Yes
- Main switches
- 1
- Alternative supply
- None
- Final subcircuits, in order on the board
- 6 rows
Circuits on the chart
6
- Ways used
- 6
- Main switch label
- MAIN SWITCH
This result is a design aid. Verify it against the current standard.
Calculation steps
- Way 1Lights
AS/NZS 3000:2018 Cl 2.10.5.2
- Way 2Lounge and bedroom sockets
AS/NZS 3000:2018 Cl 2.10.5.2
- Way 3Kitchen sockets
AS/NZS 3000:2018 Cl 2.10.5.2
- Way 4Laundry and bathroom
AS/NZS 3000:2018 Cl 2.10.5.2
- Way 5Oven
AS/NZS 3000:2018 Cl 2.10.5.2
- Way 6Hot water
AS/NZS 3000:2018 Cl 2.10.5.2
- Main switch labelMAIN SWITCH
AS/NZS 3000:2018 Cl 2.3.3.5(a)
- Board labelNot needed in a single domestic installation
AS/NZS 3000:2018 Cl 2.10.2.4 Exception 1
- LabelMAIN SWITCH
AS/NZS 3000:2018 Cl 2.3.3.5(a)
- Ways usedResult6
About this calculator
How this is calculated
You list the final subcircuits of one board in the order they sit: what each supplies, its device and rating, its active conductor, single or three phase, its RCD, and any neutral it shares. It is the same list the test schedule reads, so a link carries the circuits from one tool to the other.
The tool numbers the ways in order. A single-phase circuit takes one way and a three-phase circuit three. Each row of the chart gives the way, what the circuit supplies, its device, its RCD and its active conductor. That is how the wiring rules want a board marked: each switch, circuit-breaker, fuse and RCD tied to the part of the installation it supplies, on or beside the board. A circuit with no name fails, because nobody can tell from the chart what it feeds.
Then the board's own labels. Each main switch says MAIN SWITCH, and where a board has more than one, each names the part it controls. A main switchboard says MAIN SWITCHBOARD, except in a single domestic installation. A solar, generator or battery supply has its main switch labelled with its energy source, and a notice shows where it is isolated. A sub-board's isolating switch names the circuits it isolates. A shared neutral is marked with the actives it serves, and the chart names their ways.
The clauses ask for marking in English, legible and indelible. They set no letter height or colour, so the tool states none. The chart prints as a PDF for the board door.
| Step | Table or clause | What it decides |
|---|---|---|
| Chart of the circuits | Cl 2.10.5.2 | Each device tied to what it supplies |
| Main switch | Cl 2.3.3.5 | MAIN SWITCH, its part and its energy source |
| Main switchboard | Cl 2.10.2.4 | MAIN SWITCHBOARD, and the single home exception |
| Isolating switch | Cl 2.3.4.4 | The circuits a sub-board switch isolates |
| Shared neutral | Cl 2.10.5.5 | The actives a shared neutral serves |
| Marking | Cl 2.10.5.1 | English, legible and indelible |
Worked examples
- A New Zealand house board. The chart holds 6 circuits on 6 ways, and the main switch is labelled MAIN SWITCH. The board needs no MAIN SWITCHBOARD label in a single home.
- A shop board with solar. The chart holds 6 circuits on 6 ways, with MAIN SWITCH, MAIN SWITCHBOARD and MAIN SWITCH SOLAR labels.
- A workshop sub-board. The chart holds 4 circuits on 8 ways: the two three-phase circuits take ways 3-5 and 6-8. The isolating switch names the circuits it isolates.
Limits
The chart is as good as the list: it does not check the devices, cables or RCD arrangement. Use the circuit check, RCD arrangement and test schedule tools for those. It does not draw the board, and it does not set a form of separation or an enclosure. It covers the labels the wiring rules name; a network company or a building owner may ask for more.
See also: Switchboard labels and circuit charts, A circuit chart for a house board with solar and Circuit Check.
Questions
Each answer describes what this tool calculates. The result is a design aid. Verify against the current standard.
Does a switchboard need a circuit chart?
AS/NZS 3000 Cl 2.10.5.2 asks that each switch, circuit-breaker, fuse and RCD is marked with the part of the installation it supplies, on or beside the board. A circuit chart on the door is the usual way to do it.
Which labels does a main switchboard need?
MAIN SWITCH on each main switch, and MAIN SWITCHBOARD on the board, except in a single domestic installation. Where there is more than one main switch, each names the part it controls. A solar or generator main switch names its energy source.
How big do the labels have to be?
The wiring rules set no letter height or colour. They ask that the marking is in English, legible and indelible. The MAIN SWITCH must also stand out from other switchgear by grouping, contrasting colour or similar.
How is a shared neutral marked?
A neutral used by two or more circuits is marked with the actives it serves, by Cl 2.10.5.5. Give those circuits the same shared neutral number and the chart names their ways.
Can I use the same circuit list for the test sheet?
Yes. The circuit chart and the test schedule read the same circuit list, so a link carries your circuits from one tool to the other.
Clauses and tables this tool reads
Every clause and table, with how each was verified
Tables last checked on 1 Oct 2026.
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