Switchboard, consumer mains and submain in Australia
How Australian low-voltage notes distinguish the service path, consumer mains, main switchboard, submains and distribution boards.
What the terms name
Switchboard, consumer mains and submain are location and path terms. They show where a load schedule, voltage-drop calculation or protection note sits in an Australian installation.
A simple path is: DNSP or service context, consumer mains, main switchboard, submain, distribution board and final subcircuits. A real project may use more detail, but that sequence keeps the installation path clear.
Why the path matters
Load and cable results can be misleading if the board or cable path is unclear. A maximum-demand worksheet needs the right switchboard and load groups. A submain voltage-drop result needs the right voltage, phase arrangement, route length and entered cable data.
Consumer mains and submain wording also changes the review context. A supply-side path may involve DNSP or service conditions. A downstream submain may sit inside the project distribution design. A 230 V final subcircuit, a 400 V three-phase submain and a main switchboard MEN note should not be described as the same generic cable run.
| Term | What it usually identifies | Values to keep beside it |
|---|---|---|
| DNSP or service context | Network-facing supply condition or service basis. | Supply capacity, connection conditions and project documents. |
| Consumer mains | Supply path into the installation. | Voltage basis, route length, source conditions and DNSP notes where relevant. |
| Main switchboard | Main board where load groups, protection and MEN context may be organised. | Board label, phase arrangement, load groups and protective-device context. |
| Submain | Downstream supply path between boards or distribution points. | Cable data, route length, load basis and voltage-drop allowance. |
| Distribution board | Downstream board serving final subcircuits or local loads. | Board label, circuit list, phase allocation and protective devices. |
| Final subcircuit | Circuit from a board to the load or outlet group. | Load current, protective device, cable route and voltage-drop basis. |
Consumer mains vs submain
Consumer mains and submain can both be cable-path terms, but they are not interchangeable labels. Consumer mains points toward the supply path into the installation. Submain points toward downstream distribution between boards or sections of the installation.
That distinction matters when a voltage-drop note is reviewed. A consumer mains allowance, source condition or authority note may not be the same as the downstream design basis for a submain. The calculation can use similar arithmetic, but the project question is different.
Supply path examples
| Path section | Better wording | Why it helps |
|---|---|---|
| Service to main switchboard | Consumer mains, supply basis and main switchboard label. | It keeps network-facing context separate from downstream distribution. |
| Main switchboard to distribution board | Submain, route length, cable data and load basis. | It ties voltage drop to the intended board-to-board path. |
| Distribution board to final loads | Final subcircuit, protective device and load current. | It avoids using submain assumptions for a branch circuit. |
| Main switchboard earthing note | Main switchboard, MEN context and protective earth wording. | It keeps earthing language separate from load scheduling. |
Next checks
- If the question is load capacity, identify the switchboard and load groups before using maximum-demand arithmetic.
- If the question is voltage drop, name the path as consumer mains, submain or final subcircuit before entering length and cable data.
- If the question is phase loading, keep 230 V single-phase loads and 400 V three-phase loads visible in the board schedule.
- If the question involves service conditions, connection approval or MEN arrangement, use licensed project review and DNSP documents.
Boundaries
- This overview does not approve a switchboard layout.
- It does not size consumer mains or a submain.
- It does not decide a DNSP connection condition, MEN arrangement or final subcircuit design.
- Current project drawings, utility conditions, product data, engineering review and standards context remain controlling sources.