A blackout during lunch service, a clinic session or a workshop job costs more than lost time. Stock can spoil, bookings move elsewhere, and EFTPOS stops working.
A portable generator can keep essentials running, but only if it is sized correctly, connected properly and operated safely.
Backup power cannot restore a failed telecommunications service, so plan connectivity separately.
Key Takeaways
- Start with a critical-load list. Check both running watts and the extra power needed to start motors.
- Match the generator to your equipment. Check power quality, output and outlet compatibility, not just the advertised maximum wattage.
- Building connections require a licensed electrician. Direct appliance connections have different requirements.
- Run it outdoors, away from openings. Exhaust entering occupied spaces can cause fatal carbon monoxide poisoning.
Start with the loads you cannot lose
Walk through the premises and list what must stay on: the POS terminal and router, basic lighting, refrigeration and security.
Note each appliance’s running watts and add up the equipment that will operate together.
Allow 20 to 30 percent headroom as a starting point, then check startup demand separately. A fridge compressor or pump may briefly need several times its running power.
The generator’s continuous output must cover ongoing demand, while its starting capacity must handle equipment switching on.
Check appliance manuals for startup requirements rather than relying on a general multiplier.
For medical equipment, follow device-specific requirements and applicable clinical backup rules; don’t assume a portable generator is sufficient.
Australian mains supply is nominally 230 V at 50 Hz. Check that the generator’s voltage, frequency and outlets suit your equipment.
Many portable units have 10 A sockets; some also have 15 A sockets. A 15 A plug will not fit a 10 A socket, and improvised adaptors are not a solution.
Generator type and fuel
Inverter generators use electronics to regulate their output and often suit sensitive equipment such as tills and routers.
Check the specific model’s power-quality specifications and your equipment manufacturer’s requirements.
Enclosed inverter models are often quieter than conventional open-frame units, which may offer more output for the price.
An open frame describes the housing, not the power quality, so don’t judge suitability by appearance alone.
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Petrol is common in smaller portable units, but stored fuel deteriorates. Diesel may suit longer operating periods, depending on the model and load.
LPG avoids some petrol-storage issues, although cylinders still need compliant storage and inspection. Dual-fuel models may produce less power on LPG than petrol.
Compare fuel consumption and output for the specific model and fuel you plan to use.
If you want to compare listed capacity and fuel type, you can buy a portable generator from Macfarlane as a starting point, then confirm equipment suitability and installation needs with your electrician.
Safety and legal connection
Generators belong outdoors, well away from doors, windows and vents, with exhaust directed away from buildings.
Never run one inside a shed, garage or kitchen, even with doors open. Follow the manufacturer’s placement instructions and local safety guidance.
Fit carbon monoxide (CO) alarms in nearby occupied areas, but never treat alarms as a substitute for safe placement.
Never plug a generator into a wall outlet to power the building. This can feed electricity back into the grid and electrocute line workers or people on the premises.
For building backup, a licensed electrician must install a suitable generator inlet and changeover or transfer arrangement that isolates the mains supply.
The installation must meet applicable requirements, including AS/NZS 3000 and AS/NZS 3010.
Some appliances can instead connect directly to a generator using suitable leads, within the equipment’s ratings and manufacturer’s instructions.
Ask an electrician to confirm the required residual current device (RCD) protection, which helps protect against electric shock. Do not improvise wiring or earthing arrangements.
Keep the generator dry using manufacturer-approved protection that does not trap exhaust. Keep combustible materials away, and shut down the engine and let it cool before refuelling.
Noise matters too. In Victoria, businesses must meet EPA Victoria’s general environmental duty and applicable noise requirements.
Other states have their own rules. Check with your regulator or council, especially if the unit will run near homes or outside normal business hours.
Features worth paying for
- A CO shutoff sensor as an extra safeguard, not a replacement for safe outdoor placement.
- Electric start if staff may struggle with a pull-start engine. Remote start does not necessarily mean automatic-transfer compatibility.
- A fuel gauge, enough runtime for likely outages and an hour meter to track servicing.
- A published noise rating with its measurement distance and operating load, so comparisons are meaningful.
When a generator is not the whole answer
An uninterruptible power supply (UPS) provides immediate, short-duration backup while a generator starts or computers shut down safely.
Batteries offer quiet backup, with runtime determined by their capacity and the connected load.
Buy, hire, and how to compare
If outages are rare or seasonal, hiring may cost less, but check availability during widespread outages.
Ownership provides more control over access and maintenance, though it brings storage and servicing responsibilities.
Budget for fuel, maintenance and any electrical installation, not just the generator.
Compare continuous and peak output, fuel type, starting method, power quality, noise and compatibility with your planned connection.
Use these requirements to narrow the shortlist and confirm equipment suitability and installation needs with your electrician.
Before the first storm
Treat backup power as one part of a wider business continuity plan, then work through these checks:
- Have any required inlet and transfer equipment installed by a licensed electrician.
- Test the setup under its intended load and follow the manufacturer’s testing and servicing schedule.
- Store fuel safely and manage it according to supplier guidance.
- Check CO alarms and print clear startup and shutdown instructions.
- Choose a safe operating position away from openings, combustible materials and neighbouring buildings.
- Test communications backup for EFTPOS and routers.
FAQ
What size suits a small cafe?
Add the running watts of essential equipment, allow headroom and check compressor startup demand separately.
Coffee machines and other heating appliances can add substantial loads. Have an electrician confirm the required continuous and starting capacity.
Last Updated on October 7, 2026 by Nick Ross
