Written by Oliver Hastings on 6 November 2026
When Were Your Smoke Alarms Last Replaced? A Blakeview Job Spotlight
During a service visit in Blakeview, our electrician identified two smoke alarms requiring replacement and completed the work on the same visit. Smoke alarm replacement in Adelaide is licensed electrical work: each 240V hardwired alarm uses a photoelectric (PE type) sensor with a 9-volt battery backup, as required under South Australian legislation.
The Job In Brief
- Equipment: Two 240V hardwired photoelectric (PE type) smoke alarms with 9-volt battery backup. Ducted air conditioning system also attended.
- Suburb: Blakeview, Adelaide
- Identified: Two smoke alarms requiring replacement, found during a scheduled service visit
- What we checked: Existing alarm installation; new alarms confirmed operational after replacement
- Root cause: Out of date smoke alarms and ductwork seal failure
- Fix: Two 240V photoelectric smoke alarms replaced; ducted system serviced; minor duct repair completed
- Price guide: $1,000 to $1,500 inc GST (guide only, correct at 5 November 2026)
- Outcome: Work completed
The Fault
The visit was booked for a ducted air conditioning service. While on site, our technician identified two 240V smoke alarms as requiring replacement and completed the work during the same call as they were out of date. The alarms were 240V hardwired units, the standard type for South Australian homes approved from 1 January 1995. Any replacement of a hardwired smoke alarm involves disconnecting and reconnecting live household wiring, which is electrical work requiring a licensed electrician in this state.
What We Tested
Replacing a 240V hardwired smoke alarm involves isolating the circuit at the switchboard before the existing unit is disconnected. The replacement alarm is then wired in and power is restored. The new alarm is confirmed to activate before the job is signed off. South Australia’s Metropolitan Fire Service recommends photoelectric (PE type) alarms as the preferred residential type, as they respond to smouldering fires.
The PE type designation on the parts supplied for this job refers to photoelectric detection technology. For a 240V alarm, the 9-volt battery backup is a separate item from the mains supply. The Metropolitan Fire Service advises that the backup battery should be replaced annually, and that the full alarm unit should be replaced after 10 years regardless of power source, as older alarms may not function reliably.
How We Fixed It
Two 240V photoelectric smoke alarms with 9-volt battery backup were fitted in place of the existing units. These alarms are hardwired to the household mains supply, with the battery providing backup during a power interruption. The photoelectric sensor detects smoke particles by monitoring a light beam inside the detection chamber. When smoke enters and scatters the beam, the alarm activates.
As part of the same visit, the ducted air conditioning system was serviced, and a minor duct repair was identified and completed.
Summary
| Stage | What we did | What it showed |
|---|---|---|
| Identification | Smoke alarms identified as requiring replacement during service visit | Two alarms to replace |
| Circuit isolation | Isolated smoke alarm circuit at switchboard | Safe to disconnect existing alarms |
| Alarm replacement | Fitted two 240V PE type alarms with 9V battery backup | New alarms confirmed operational |
| Ducted service | Serviced ducted air conditioning system | Service completed |
| Duct repair | Minor duct repair completed | Repair completed |
Key Takeaways
- Replace alarms after 10 years. The Metropolitan Fire Service advises replacing all domestic smoke alarms after 10 years, regardless of whether they are battery powered or hardwired. The service life date is usually printed on the base of the alarm.
- 240V alarms are the standard for most SA homes. South Australian legislation requires 240V hardwired smoke alarms with battery backup in homes approved from 1 January 1995. If a home changed ownership on or after 1 February 1998, the incoming owner has 6 months from title transfer to bring the alarms into compliance. The MFS legislation fact sheet sets out the full requirements.
- Test monthly, replace the battery annually. Press and hold the test button on each alarm once a month until it sounds. For hardwired alarms, the Metropolitan Fire Service recommends replacing the 9-volt backup battery annually, timing it to daylight saving changes. To test the battery backup on a hardwired alarm, isolate power at the switchboard first, then press the test button.
- Replacing a hardwired alarm is a licensed electrical job. Disconnecting and reconnecting a 240V hardwired alarm involves live household wiring. This work must be carried out by a licensed electrician. If a technician is already on site for another job, it can often be attended to in the same call.
- Ageing air conditioning systems are worth monitoring. If other systems on the property are showing signs of age, it pays to plan ahead. Our repair or replace calculator can help you think through the options before a system fails at the worst possible time.
The Resolution
Both 240V photoelectric smoke alarms were replaced and confirmed operational. The ducted air conditioning service and minor duct repair were also completed on the same visit. The technician noted several other hi-wall split systems on the property showing signs of age and advised keeping an eye on them. If anything needs attention, the team is reachable on 08 8296 7888 or through the contact page.
“Smoke alarms get overlooked because they work quietly for years. The ten-year replacement rule exists because they don’t work quietly forever.” Oliver Hastings, T&K Airpower
Frequently Asked Questions
How long do smoke alarms last in Australia?
The Metropolitan Fire Service advises replacing all domestic smoke alarms after 10 years, regardless of whether they are battery powered or hardwired to 240V mains. Older alarms may not function reliably. The service life date is usually printed on the base of the unit.
Do I need a licensed electrician to replace a smoke alarm?
If the alarm is hardwired to 240V mains, yes. Disconnecting and reconnecting a hardwired alarm involves live household wiring, which is licensed electrical work in South Australia. Battery-only alarms that clip into an existing base may be different, but most homes approved from 1995 onward have hardwired units.
What is a PE type smoke alarm?
PE stands for photoelectric. A photoelectric alarm uses a small light beam inside the detection chamber. When smoke particles enter and scatter the beam, the alarm activates. The Metropolitan Fire Service recommends 240V photoelectric alarms that are interconnected as offering the best protection in a residential home.
What does the 9-volt battery backup do in a hardwired smoke alarm?
The battery keeps the alarm operational if the household mains power is interrupted. The 9-volt battery is separate from the hardwired mains connection and should be replaced annually. The Metropolitan Fire Service suggests timing battery replacements to daylight saving changes so they are not forgotten.
What are the smoke alarm rules in South Australia for existing homes?
South Australian legislation requires 240V hardwired smoke alarms with battery backup in homes approved from 1 January 1995. For older homes where ownership changed on or after 1 February 1998, the incoming owner has 6 months from title transfer to meet this standard. The full requirements are on the Metropolitan Fire Service website.
Can smoke alarms be replaced during an air conditioning service visit?
Yes, if a licensed electrician is on site. T&K Airpower technicians hold both refrigeration and electrical licences, so electrical items such as smoke alarms can be attended to during an air conditioning service visit rather than requiring a separate booking.
How often should I test my smoke alarms?
The Metropolitan Fire Service recommends pressing and holding the test button on each alarm once a month until it sounds. For hardwired alarms, testing the battery backup requires isolating power at the switchboard first. Alarms should also be vacuumed using a soft brush attachment every six months to prevent dust build-up.
Need Help?
For smoke alarm replacement, electrical repairs, or air conditioning servicing anywhere in Adelaide, call T&K Airpower on 08 8296 7888 or book online. Trading since 1996, licensed for electrical and refrigeration work, and authorised warranty agents for Mitsubishi Electric, Temperzone and Hitachi. We repair first.
