Secondary dwellings — granny flats, backyard studios, workshops, and large sheds — are increasingly popular across Brisbane and Moreton Bay. Whether you’re housing a parent, building a home office, or creating a serious workshop, the electrical fitout needs to be done by a licensed contractor. Done incorrectly, it creates safety hazards and can complicate insurance claims and future property sales.
What Electrical Work Does a Granny Flat Need?
A granny flat intended for habitation requires its own full electrical installation, typically including:
- A sub-switchboard with RCDs (safety switches) and circuit breakers
- Separate metering if you plan to lease it or want independent electricity billing
- Power points in every room (AS/NZS 3000 requires at least one double GPO per room)
- Lighting circuits and any fixed appliances — range, hot water system, air conditioner
- Interconnected photoelectric smoke alarms compliant with Queensland’s updated laws
- An underground or overhead cable run from the main switchboard to the dwelling
Sub-Board vs. Separate Meter — Which Do You Need?
If the flat is for a family member and the electricity bill stays with the main household, a sub-board is usually sufficient. If you intend to rent it out — even informally — Energex requires a separate NMI (network metering identifier) so each dwelling can be billed independently. Your licensed electrician lodges the metering application with Energex on your behalf. Note that Energex’s connection process can take two to four weeks, so plan ahead.
Underground Cable Runs
Most Brisbane granny flats and sheds are fed by an underground cable trench. The cable must be correctly rated for the load, buried at the required depth (typically 600mm in general ground, 500mm under concrete slabs), and run in conduit where mechanical damage is possible. All trenching and underground wiring must comply with AS/NZS 3000 and be notified to the Electrical Safety Office.
Smoke Alarm Requirements for Granny Flats
Queensland’s smoke alarm laws require interconnected photoelectric smoke alarms in every bedroom, in hallways connecting bedrooms, and on each level of a dwelling. These requirements apply to all new granny flats and to any existing secondary dwelling that is sold or leased. Non-compliance can void landlord insurance and expose you to liability under the Residential Tenancies and Rooming Accommodation Act 2008.
Large Sheds and Workshops
Sheds don’t need the same level of fitout as a granny flat, but the rules still apply:
- All wiring must be done by a licensed electrical contractor — homeowners cannot legally install their own power points or lighting in Queensland
- An RCD-protected circuit or sub-board is required
- Weatherproof fittings must be used in outdoor or partially exposed areas
- Three-phase power is needed for large machinery such as welders, lathes, or industrial air compressors
A Notification of Work must be lodged with the Electrical Safety Office for any new wiring regardless of the job size. There are no exemptions for small or “temporary” installations.
Do I Need Both a Building Permit and an Electrical Permit?
Yes, in most cases. Brisbane City Council (or your local council) requires a building approval for a secondary dwelling or substantial shed. Separately, all electrical work requires a Notification of Work filed by your licensed electrical contractor with the Electrical Safety Office. These are independent processes — your builder manages the building approval; your electrician manages the electrical notification.
How Long Does the Electrical Work Take?
For a typical granny flat, allow one to two days for the electrical fitout — cabling, sub-board, GPOs, lights, smoke alarms — plus an additional day for trenching if the cable run is long or the ground is rocky. If a separate Energex meter is needed, add the connection lead time of two to four weeks on top.
Get It Done Right from the Start
Integrated Trade Services provides granny flat and shed wiring across Brisbane, Moreton Bay, and the Sunshine Coast. We handle the Notification of Work, sub-board installation, Energex metering applications, and smoke alarm compliance — so there are no surprises when the building inspector comes through. Contact us to discuss your project, or see our full electrical services in Brisbane and other trade services.
Related guides
- Switchboard upgrades in Brisbane: costs & warning signs
- Queensland smoke alarm laws explained
- Do I need a safety switch in Queensland?
Need a licensed Brisbane electrician? See our electrical services or get in touch for a quote.