Smart home rough-in: wiring decisions before the lining goes on

Most of the cost in a smart home is not in the devices. It is in the access. A cable run that takes ten minutes while the frames are open can take half a day once the plasterboard is on, the painter has finished and the floor is laid. That is the whole logic of smart home rough-in: the decisions you make at first fix determine what is still possible at handover, and what has become a variation.

The trap is that smart home work rarely arrives as a complete specification. It arrives as a conversation with the client, a list of appliances they have already bought, or a single line in the scope about “data points”. If that conversation happens after the lining is up, you are not roughing in, you are retrofitting a finished house.

This article is about the provisions that belong in the construction programme before sheeting: what to run, what to leave spare, who is allowed to do the work, and how to record it so the next trade is not guessing.

Why smart home rough-in is a sequencing problem, not a product problem

Products change faster than the building. A device chosen at design stage may be superseded, discontinued, or replaced by something the client saw at a home show. You cannot future-proof against that, and you should not pretend to. What you can do is make the physical installation indifferent to the product.

That means treating the rough-in as infrastructure: power where a device might sit, a pathway that can carry a cable from one point to another, and enough space at the termination point to fit something that does not exist yet. Infrastructure decisions are cheap in the frame stage and expensive later, while product decisions are reversible at almost any time. Sorting the two apart is the first thing to do with a client.

There is also a commercial reason to lock the brief early. Smart home scope is the most common source of post-contract variations on residential jobs, because it is the part of the scope the client understands least at signing and cares about most at handover. Every provision you build in at first fix reduces the number of variations you will be arguing about while trying to reach practical completion.

Who is allowed to do the work: electrical and cabling are separate

Electrical work in NSW is regulated work, and the general duties around electrical safety on a construction site are set out by Safe Work Australia. Those duties cover the obvious things: de-energising before work, testing before you assume a circuit is dead, protecting leads and temporary supply, and keeping unqualified people away from live parts. On a smart home job, the risk profile grows because there are more circuits, more low-voltage cabling in the same wall cavities, and often more trades working around energised equipment.

What catches builders out is that data cabling is regulated separately. The ACMA cabling provider rules require that cabling work on customer premises is done by a registered cabling provider, and registration is tied to competency in the type of cabling being installed. A licensed electrician is not automatically a registered cabling provider, and a registered cabling provider is not automatically an electrician. On a job with structured data cabling, alarm wiring, intercom and audio distribution, you need to know which of your subbies holds which registration, and you need it in writing before they start.

The practical consequence: do not let the electrician quietly run the data “while they are there” unless they hold the right registration, and do not assume the security installer’s work is covered by someone else’s licence. If the work is not done by a registered provider, the client carries the compliance problem, and you carry the reputational one, because you engaged the trade.

Decisions to settle at the pre-rough-in meeting

Hold a dedicated meeting before the electrician first-fixes. Not a phone call, not a note on the plan. Walk the frame with the client and the trades, and settle the following on site.

• What is automated now, and what is only provisioned. A client who wants motorised blinds later still needs power at the head of the window now. A client who wants a camera later needs a cable path and a mounting point, even if the device is not purchased.
• Where the control equipment lives. Distribution boards, network equipment, amplifiers and controllers need a ventilated, accessible, lockable location with power and a data path. A cupboard with no ventilation and no power is not a comms room.
• Switch and sensor positions. Many automation switch modules need a neutral conductor at the switch location. If the wiring is done without one, the client’s preferred system may be ruled out before they have chosen it.
• Box depth and mounting heights. Touchscreens, wall panels and some sensors need deeper boxes and specific heights to suit the user. Height is a client decision, not a trade default.
• Coverage and sightlines. Access points and cameras need to be positioned where they will actually work. That is a walk-around decision, not a plan decision.
• Who supplies what. Devices supplied by the client, the electrician or the AV contractor need to be named, with delivery dates, because a missing device at second fix stalls the whole job.

Record the outcomes on a marked-up plan and get the client to sign or acknowledge it. A marked-up plan is the cheapest variation control instrument you have.

Separation, protection and the cables you cannot see later

Once the sheeting goes on, nobody knows where anything runs unless it was recorded. Two rules follow from that.

First, keep services separated. Power and communications cabling should not share the same enclosure or be run tight together in a way that lets mains voltage onto a data circuit, and cable that runs through a wall cavity needs protection from the screws and fixings that will follow. Where a cable crosses a stud, protect it. Where it passes through a plate, protect it. Where it might be drilled through later by someone hanging a cabinet, either protect it or make its location obvious.

Second, anything buried in the ground is a locating problem for the life of the building. Before any excavation on site, lodge an enquiry with Before You Dig Australia and treat the response as information, not as a clearance to dig. If you are adding buried conduit for a future gate, shed or outdoor structure, that is the moment to record it, because the next person on the site will not know it is there.

For the cables inside the building, the record is what matters. Photograph every wall before sheeting, with a tape or a fixed reference in the frame so distances can be scaled. Note the depth of each run and the height of each box. File the images with the as-built documents rather than leaving them on a phone.

Spare capacity is the cheapest future-proofing available

You cannot predict what a client will want in five years. You can make it easy to add. The provisions that cost least at first fix and save most later are unglamorous:

• Conduit with draw wires from the comms location to each major room, so a cable can be pulled later without opening a wall.
• Spare capacity in the cable path — a conduit that is already full is no better than no conduit.
• Neutral at switch locations throughout, not just where automation is planned today.
• Deeper boxes at likely panel and screen locations, so a device can be recessed rather than surface-mounted.
• Power at the head of windows, at the eaves line and at gate and outdoor structure locations, where the client will eventually want a device and the wall will be closed.

None of these are large line items at first fix. All of them become disruptive, dusty, client-visible work if they are added later, and that work is the work clients remember when they are asked to recommend you.

Interaction with energy efficiency and BASIX requirements

Added services interact with the thermal and energy performance of the building. The NCC energy efficiency provisions deal with the building fabric, services and the energy used by the home, and a BASIX certificate for a NSW dwelling sets out commitments that must be built. If the smart home scope adds equipment, changes lighting, adds a ducted or split system, or requires penetrations through the thermal envelope for cabling or ventilation, those commitments need to be checked before the work is done, not discovered at inspection.

The common failure is a change made on site for convenience — a cable run that compromises insulation, a controller installed in a sealed cupboard, a service penetration that is not sealed. Each of those can affect the performance the certificate and the NCC provisions assume. If a change is needed, work out whether it alters any committed item and, if it does, deal with it through the correct process rather than hoping the certifier does not notice. Our article on the BASIX certificate for NSW builders covers how those commitments are documented and varied.

The same logic applies to mechanical services. Adding a split system to a room to make a home office comfortable is a common smart home add-on, and it has its own installation and compliance requirements, covered in our article on split system air conditioner installation in NSW.

Worked example: a builder in western Sydney

A builder in western Sydney is contracted for a knockdown rebuild for a client who mentions, at contract signing, that they want “a smart home”. The scope includes a data point allowance and nothing more. The electrician first-fixes to the plan, the cable is run, the walls are sheeted, and the job progresses to fit-out.

At fit-out, the client confirms their system. The automation modules they have chosen need a neutral at each switch location. The switch wiring was done without one. The touchscreen panels need deeper boxes than were installed. The camera positions they want are on a wall with no cable path and no power, and the access point in the living area is behind a foil-backed insulation layer that was installed after first fix.

Every one of those is a physical problem, not a programming problem. The switch wiring cannot be changed without opening walls at every switch location. The camera and access point fixes mean surface trunking or new penetrations. The builder is now negotiating variations against a client who believes the smart home was included, while the programme for practical completion slips and other trades are held up waiting for access.

The alternative was not more expensive equipment. It was a pre-rough-in meeting, neutral conductors throughout, deeper boxes at the two panel locations, a conduit with a draw wire to each major room, and a marked-up plan the client signed. The builder would have spent a fraction of the variation cost at frame stage and avoided the argument entirely.

Documentation, handover and the next trade

Smart home installations are the least self-documenting part of a house. Cables are hidden, terminations are behind plates, and the equipment may be configured by a contractor who never returns. Your handover pack should include an as-built services plan showing cable routes and box locations, photographs taken before sheeting, a schedule of what was installed and who installed it, and the registration details of the cabling provider. If the client later sells, that pack is the difference between a buyer’s inspector writing “services not traceable” and a clean report.

It also protects you. If a fault appears after handover, the first question is who installed what. A record that names the trade for each system, with the testing results for the data cabling, resolves that question quickly instead of turning into a dispute about your supervision.

Finally, treat the smart home as a system with a lifespan. Devices will fail, software will stop being supported, and the client will need someone to work on it. Leave the next person a fighting chance: labelled cables, accessible equipment, and a record of what is where. That is the professional standard, and it costs almost nothing at first fix.

If you want the compliance side of this in a structured form, the guide to how NSW builder CPD works explains how the requirements are structured, and the PointCPD course catalogue lists the courses that cover technology and compliance topics for licensed builders. Our related article on cyber security for a building business is worth reading if you are storing client system credentials or managing connected equipment after handover.

Questions builders ask

• Electrical
• Rough-In
• Smart Home

Published 19 July 2026. General information for builders, not legal, financial or engineering advice for a specific job. Check current requirements with the relevant regulator or standard before relying on them.