Introduction
Smoke alarm specification is one of those items in a new build project that can appear straightforward on paper but create real friction at consent and sign-off if it is not handled correctly from the start. Get it right at the specification stage and it is a tick in the box. Get it wrong and you are looking at a variation, a revisit from your electrician, and a delay to practical completion.
This guide is written for builders and project managers working on new residential builds and consented renovations in New Zealand. It covers exactly what NZS 4514:2021 requires, how to document it correctly for a building consent, and the specification decisions that will save you time and cost over the life of the project.
The Regulatory Framework
Smoke alarm requirements for new residential buildings in New Zealand are set out in the NZ Building Code under Clause F7 (Warning Systems), with NZS 4514:2021 as the referenced performance standard. Any residential building consent granted from November 2021 onward must comply with NZS 4514:2021. Full technical details are available on our NZ Building Code page, but the key requirements for new builds are summarised below.
What NZS 4514:2021 Requires for New Builds
Alarm type
- All smoke alarms must be photoelectric
- Ionisation alarms are not compliant for new builds
- Heat alarms (not smoke alarms) are required in kitchens and sculleries separated by doors, and recommended for garages and laundries
Power source
- Alarms must be either mains-powered (230V with backup battery) or long-life battery-powered (10-year sealed lithium)
- Replaceable 9V battery alarms are not compliant for new builds
Interconnection
- All alarms must be interconnected, so that activation of any single alarm causes all alarms in the dwelling to sound
- Interconnection can be achieved via hardwired cabling or wireless RF communication
- Wireless RF interconnection is compliant and does not require cabling between alarm units
Minimum placement
- At least one alarm on every level of the dwelling
- At least one alarm within 3 metres of every bedroom door, measured along the ceiling
- At least one alarm in every living area and dining area
- Alarms in all internal hallways that connect sleeping areas to the rest of the dwelling
- A heat alarm in the kitchen and scullery (where separated from living areas by a door)
Planning Smoke Alarm Placement at the Design Stage
The time to think about smoke alarm placement is during the design and consent documentation phase, not during the fit-out. Specifying alarm locations on your consent plans creates clarity for your electrician, avoids disagreements during inspection, and ensures the installation is compliant before the first nail goes in.
When reviewing floor plans for alarm placement, work through the following:
- Mark one alarm location on every level, in a central ceiling position in the main hallway or living area
- Mark alarm locations within 3 metres of every bedroom door
- Confirm whether the kitchen is open-plan (smoke alarm in the living zone is sufficient) or separated by a door (heat alarm in the kitchen, smoke alarm in the adjacent hallway or living area)
- Note garage and laundry positions for heat alarm placement
- If the dwelling has more than one storey, confirm alarm coverage on each level including any mezzanine or loft sleeping areas
Hardwired vs Wireless Interconnection: What to Specify
Both hardwired and wireless interconnection are compliant under NZS 4514:2021. The choice between them typically comes down to build type, client preference, and cost.
Hardwired (mains-powered) interconnection
- Requires cabling between alarm locations during the framing stage
- Alarms draw primary power from the 230V circuit with a backup battery
- Wiring must be completed by a licensed electrician
- Cabling decisions need to be made before interior linings go in
- Well-suited to new builds where running cabling is straightforward during construction
Wireless (RF) interconnection
- No cabling between alarm units required
- Alarms communicate via radio frequency and pair during commissioning
- Battery-operated units can be installed at any stage of the build, including after linings are in
- CAVIUS wireless alarms support up to 50 devices per network and include both battery operated and mains powered options that integrate within the same RF network
- Useful where a mix of mains-powered alarms (main living areas) and battery-operated alarms (bedrooms) is specified
For most new builds, a combination approach works well: mains-powered alarms hardwired in the main living areas and hallways, with battery-operated wireless alarms in bedrooms. This provides mains reliability in the highest-traffic zones while keeping bedroom installation simple.
Documenting Your Specification for Consent
Consent documentation for smoke alarms should include:
- Alarm locations marked on floor plans for each level
- Specification of alarm type (photoelectric smoke alarm or heat alarm) for each location
- Power source specification (mains-powered or 10-year sealed battery)
- Confirmation of interconnection method (hardwired or wireless RF)
- Product specification including model number and compliance standard (AS 3786:2014 or equivalent)
If your consent documentation does not specify alarm locations, the building inspector may require additional information before granting consent or signing off the installation. Getting this detail into your plans upfront removes that friction.
At Sign-Off: What Inspectors Will Check
At the final building inspection, the inspector will verify that the installed alarm system matches the consented specification. Common issues that delay sign-off include:
- Alarms installed in locations that do not match the consented plan
- Smoke alarms installed in kitchens or other zones that require heat alarms
- Replaceable battery alarms used where long-life battery or mains-powered alarms were specified
- Alarms that are not interconnected or where interconnection has not been tested
- Missing alarms in required locations (particularly hallways connecting sleeping areas)
Testing the full interconnected system before the inspection is straightforward: activate the test button on one alarm and confirm that all other alarms in the network sound within a few seconds. If any alarm in the network does not respond, diagnose and resolve before the inspector arrives.
Working With Your Electrician
Smoke alarm installation in a new build involves both the builder and the electrician. Clear communication between the two avoids duplication of effort and gaps in the installation.
- Confirm the interconnection method (hardwired vs wireless) before framing, so cabling decisions are made at the right time
- Share the floor plan with alarm locations marked so the electrician can plan their rough-in accordingly
- Confirm who is responsible for commissioning the wireless network (pairing the alarms) and testing the full system
- Ensure the electrician retains product documentation and compliance certificates for each alarm unit installed
Electricians installing CAVIUS alarms can register their installations through the InTouch warranty support programme, which provides a structured post-installation support pathway and covers the client directly for warranty issues after the job is done.
Key Takeaways
Specifying a compliant smoke alarm system for a new build consent is not complicated when the requirements are understood upfront. The core checklist:
- Photoelectric smoke alarms only (no ionisation)
- 10-year sealed battery or mains-powered (no replaceable 9V batteries)
- All alarms interconnected, hardwired or wireless RF
- Minimum placement: one per level, within 3 metres of each bedroom door, in all living areas and hallways
- Heat alarms in kitchens, garages, and laundries
- Alarm locations documented on consent plans
- Full system test completed before the final building inspection
On Point Distribution supplies CAVIUS alarms to builders and electricians through trade channels across New Zealand. For specification advice on a new build project, contact our team via the trade enquiry page.