Switchboard Specification
March 2026 · 7 min read
A good switchboard specification NZ has one job: remove ambiguity. It should define the board clearly enough that the project team, manufacturer and buyer all understand what is being supplied, what technical basis it needs to meet, and what assumptions should not be left open.
When a specification is vague, important parts of the board scope get interpreted differently by different parties. That leads to inconsistent quotations, late design changes, scope gaps, programme delays and commercial disputes that were avoidable at the start.
A stronger switchboard specification does not need unnecessary detail. It needs the right information in the right places.
For most projects, the specification becomes the foundation for both pricing and manufacturing. If it is too general, the quote will be based on assumptions. If it is clear, the board can be reviewed against a defined scope.
That helps with like-for-like comparison of quotations, better design coordination, fewer late changes, clearer responsibility boundaries and a more reliable procurement process. In short, a good specification reduces uncertainty for everyone involved.
Before looking at the detail, a useful way to test any specification is to check whether it answers these five practical questions:
If any of those are unclear, the specification may look complete on paper while leaving real risk in the project.
Start with the basic identifiers so the board is clearly tied to the job. This includes the project name, site location, drawing or document references, board designation or tag, revision status and the responsible consultant or designer. It sounds administrative, but it matters. It ensures all parties are working from the same scope basis.
The specification should explain what the board is intended to do. Is it a main switchboard, distribution board, services board, plant board, replacement in an existing installation, or a custom assembly for a specific application? The scope of supply should be defined as clearly as possible, including whether the board is new or replacement work, what equipment and functions are included, and what exclusions apply.
This is one of the most important parts of any specification. It should include the supply characteristics, main rating, incomer arrangement, busbar requirements and any system configuration information relevant to the board. Without the electrical basis, the switchboard cannot be priced or designed with confidence.
The prospective short-circuit current at the point of installation should be stated clearly rather than assumed. If it is known or has been calculated, it should be included. This can materially affect switchgear selection, construction basis and cost. If it is omitted, the quotation will rely on assumptions that may need revision later.
For most projects, the outgoing schedule is central to the whole board definition. It identifies circuit quantities, device types, feeder responsibilities, space and layout implications, and the actual functional scope of the board. A specification without a useful outgoing schedule is only partly complete.
If a particular form of segregation is required, it should be stated explicitly. The nominated form can affect internal construction, compartmentalisation, board size and pricing. It should not be left to inference or assumption.
The board should be specified for the environment it will actually face in service. Useful inputs include whether the location is indoor or outdoor, contamination conditions, washdown or moisture exposure, IP rating requirement, material or finish expectations, mounting arrangement and any weather or durability considerations. This section is especially important for boards in plant areas, service yards, industrial spaces or existing facilities with non-standard conditions.
Not every switchboard is simply a collection of protective devices. Some projects require metering, monitoring, control interfaces, interlocking, load-specific functions or special operational arrangements. If these are not stated clearly they can be missed or under-allowed in the quotation.
This is one of the most commonly under-specified areas. Access limitations, space constraints, existing cable entry limitations, replacement sequencing issues, shutdown windows, lifting or transport constraints and installation location realities are not secondary details. In upgrade and replacement work especially, they can be major drivers of design and cost.
A complete specification should explain what testing, compliance evidence and project documentation are expected. Depending on the project that may include testing requirements, compliance expectations, documentation deliverables, drawing requirements, labelling expectations and project handover information. This gives the manufacturer a clear picture of what the final deliverables need to include, not just what the board itself needs to contain.
If delivery timing, shutdown windows or staged installation matter, the specification should say so. Programme constraints can influence manufacturing planning, board format, staging strategy and commercial response. A technically sound specification can still be incomplete if the timing expectations are not captured.
Even experienced project teams sometimes leave out details that later prove important. The most common omissions are:
These omissions are often the reason quotations come back with clarifications, exclusions or scope assumptions that need to be worked through before a reliable comparison can be made.
A switchboard specification should do more than describe the board in broad terms. It should define the electrical, physical, environmental and commercial basis clearly enough that the board can be priced and built with confidence.
The best specifications reduce ambiguity early. That helps consultants, contractors, facility managers, procurement teams and switchboard manufacturers all work from the same basis, with fewer surprises later in the project.
Where engraved circuit directories, identification plates or duty labels are required as part of the switchboard build, these should be noted in the specification. See Clive Wilson’s engraving service for available options.
Ready to put together a switchboard specification for your project?
Clive Wilson Switchboards · 31–33 Clyde Street, Invercargill · 03 218 3459
