स्विचबोर्ड सर्किट चार्ट

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.

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.