Turnkey switchrooms, MCC rooms and control rooms, fitted out with CWS-manufactured LV switchboards, fully tested before they leave the workshop, then craned into place on your site. Designed in Invercargill. Delivered nationwide.
A prefabricated switchroom is a factory-built, transportable enclosure housing switchboards, motor control centres, protection and control equipment. Also called a modular plant room, MCC room, control room, modular substation or e-house, it is fitted out and tested off-site, then delivered complete and craned into position, ready for final connection.
Instead of building a room on site and then installing electrical equipment into it, the room and the equipment arrive as one tested assembly. Site works and switchroom manufacture run in parallel, and the factory acceptance test happens before anything ships. The switchboards are manufactured in our Invercargill workshop, and the completed room is delivered throughout New Zealand.
The room is built to suit the switchboard lineup. Where a standard container suits the duty we will use one, but most rooms are custom-built to the equipment.
The room is sized and arranged to the switchboard, the working space and the access it needs. The equipment sets the room, not a catalogue.
A sealed steel shell, blasted and painted to specification. What arrives on site is a finished, dry room, not a frame waiting to be closed in.
Built to be craned and trucked fully loaded, with the lifting arrangement engineered for the room rather than improvised at delivery.
Where a standard 20 ft or 40 ft container suits the duty the room is built in one. The format follows the equipment and the site, not the other way round.
We engineer the electrical design, manufacture the switchboards, and carry the fit-out, testing and documentation. Structure and building works are delivered with established specialist partners.
One tested assembly, not a building and a separate electrical package.
The room arrives fitted out and tested. Site scope is typically foundations, incoming connections and commissioning, with our support through connection and energisation.
Mining, data centres and critical power sites each ask for something different. These are the options most often built into a room.
Transformer and switchroom mounted on a common prefabricated skid, delivered and set as one package.
Very early smoke detection where standard point detection is not enough for the risk or the environment.
Arc fault relays and protection schemes specified in where the fault level and duty call for it.
Where the project specifies an internal arc classification for the switchboard.
Suppression as well as detection, to the fire engineering requirements set for the room.
Modbus, Profibus or hardwired control and monitoring, brought out to your system.
Not an exhaustive list. Tell us the duty and the environment and we will scope the room to it.
The question that decides most prefabricated switchroom projects. A typical split, confirmed in writing with your quotation.
Our scope
Your scope
The New Zealand sectors that most often specify a room rather than a board on its own.
Pump station MCC rooms and treatment plant switchrooms for councils and industry.
Dairy, meat, timber and manufacturing plants adding capacity without a building project.
Switchrooms and control rooms built for remote sites and harsh conditions.
Housed distribution for facilities that cannot tolerate downtime.
Grid-connection rooms, inverter and LV rooms, control buildings for PV and BESS.
Housed distribution for charging hubs, ports and electrified fleets.
Civil works run on site while the room is built in the factory, so the two programmes overlap instead of running end to end.
Full factory acceptance testing of the complete room, witnessed if you want to be there.
The room arrives fitted out. Site scope drops to foundations, connections and commissioning.
Fewer trades on site for less time, in a market where site electricians are hard to book.
Already have a single line diagram?
Send it through with your load schedule and site constraints and we will scope the room around it.
Most switchroom suppliers start with a building and add the electrical. We start with the part that matters: the switchboard. CWS has manufactured industrial LV switchboards in Invercargill since 1971, operates an ISO 9001-certified quality management system, and designs and verifies LV assemblies to AS/NZS 61439 on Simotrol, Logstrup, Schneider Prisma and Quantum platforms. The boards, the powder coating, the laser-engraved labelling and their factory acceptance testing all happen under one roof. The room is built around them.
The same workshop has supplied switchboards to Fonterra, Meridian Energy, NZAS and Alliance Group.
The complete room is tested as one assembly before it is dispatched. Boards, control gear, lighting, small power, HVAC and fire detection, all working together on the workshop floor, with the results documented.
Operators and consulting engineers are welcome to attend. Watching your room run before it ships takes risk out of site commissioning, and it is a great deal easier to change something in the workshop than on a live site.
This is the whole argument for prefabrication. Your site works and the factory build do not queue behind each other.
Before anything is priced, your single line diagram, load schedule and specification are read against each other. Where they disagree, you hear about it before the quotation goes out rather than after the boards are built. That is where most of the cost risk in a switchroom sits.
Off site, in the factory
On your site
Programme depends on room complexity and equipment lead times, and is confirmed with your quotation. How switchboard lead times work →
The compliance pack procurement audits ask for, supplied with the room rather than chased afterwards.
For the switchboard assemblies
For the complete room
Design verification and type testing apply to the switchboard assemblies. The room itself is engineered to the project-specific structural, fire and environmental requirements, and the documentation supplied for it is agreed at design.
Every switchroom is engineered to the project-specific electrical, structural, fire, environmental and network-owner requirements. The table below shows what we design to; the applicable editions and any additional requirements are confirmed in your project’s standards register.
| Item | What we work to |
|---|---|
| LV assemblies | AS/NZS 61439, design verified, with full test documentation |
| MV integration | Considered per application, alongside network-owner requirements |
| Wiring | AS/NZS 3000 |
| Enclosure ratings | IP rating to suit environment (AS/NZS 60529) |
| Structural | Wind, snow and seismic to the loading standards and importance level set by the project’s structural designer |
| Fire and HVAC | Detection, suppression and climate control to project specification |
| Finish | Blasted and painted to specification, paint system and colour to suit the site environment |
The more of this we have, the tighter the number and the fewer questions come back.
If some of this is not settled yet, send what you have. We will come back with the questions that actually change the price, not a list of everything.
The questions specifiers and procurement teams ask first.
A factory-built, transportable enclosure housing switchboards, MCCs and control equipment, fitted out and tested off-site, then delivered complete and craned into position for final connection on site.
The structure, HVAC, fire detection, lighting, small power, cable management, earthing and the switchboards themselves, delivered as one tested assembly. Site scope is typically foundations, incoming connections and commissioning.
Any size the equipment needs. Standard 20 ft and 40 ft shells where they suit, and custom-built enclosures where they do not. The room is sized to the switchboard lineup and the working space around it, so send your single line diagram and load schedule and we will size it to the job.
The switchboard assemblies inside the room are designed and verified to AS/NZS 61439, with full test documentation supplied. The room itself is engineered to the project-specific structural, fire and environmental requirements.
It depends on size, equipment and environment. A small room starts in the tens of thousands; larger or high-specification builds run well beyond that. Send your single line diagram and load schedule for an accurate quotation.
Programme depends on room complexity and equipment lead times, and is confirmed with your quotation. Because the room is built while site works proceed, overall project time is usually shorter than building on site.
Yes. The room is built to be lifted and transported to site, so it can be lifted and moved again later. Tell us at the design stage if relocation is likely, so the structure, fit-out and cable entry suit it.
Structural design, importance level and consenting sit with the project’s responsible structural designer and consent authority. We design and build to their requirements and provide the supporting documentation for our scope.
The boards that go inside the room: MSBs, MCCs, MSSBs and distribution boards to AS/NZS 61439.
MCCs from 63A to 3,200A, delivered loose or fitted inside a prefabricated switchroom and tested as one assembly.
How lead time is actually built up, platform by platform, and what moves it.
Send your single line diagram, load schedule and site details, and we will come back with a scoped proposal.
