Generac Install Day: What Actually Happens When We Fit a Home Standby Generator

What actually happens on the day a Generac home standby generator is installed? Four things: the unit is set on its pad outside, a licensed gas fitter connects the fuel supply, a Level 2 electrician fits the automatic transfer switch at your switchboard and wires the backed up circuits, and the whole system is commissioned with a simulated blackout before anyone leaves. The sizing, quoting and any approvals happen before the truck ever arrives.

⚡ Quick Answers: Generac installation

• What does a Generac install cost in Sydney? Typically $12,000 to $25,000+ fully installed, depending on the model and the switchboard work involved. See our Generac cost guide for the breakdown.
• Which models are we talking about? The Guardian range in 10, 13 and 20 kVA sizes, single phase for the 10 and 13, three phase for the 20.
• What fuel does it run on? Natural gas or LPG, with a tool free conversion between the two.
• How fast does it take over in a blackout? The automatic transfer switch starts the generator and switches your circuits across in about 45 to 75 seconds.
• Do I need council approval? Sometimes, depending on your property and siting. Our guide to home generator council approval in NSW covers when it applies.
• How loud is it? Around 55 to 59 dB(A) depending on model, about the level of a normal conversation.

1. Before install day: sizing and approvals

The install only goes smoothly because of what happens first. We run an on site load assessment to work out what you actually need backed up, then size the unit accordingly; the difference between the Guardian 10, 13 and 20 kVA models is real money, so we do not guess. You can get a feel for your own numbers in two minutes with our free generator load calculator.

This stage also settles siting, fuel supply and whether your property needs council approval, plus a written quote covering the unit, the transfer switch and any switchboard work.

2. The pad and position

The generator lives outdoors on a firm, level base, positioned to satisfy the manufacturer's clearance requirements from windows, doors, vents and boundaries, with service access around it. Position affects everything downstream: gas run length, cable run length, and how much you ever hear it. Getting it right on paper is cheaper than moving a 200 kilogram machine later.

3. The fuel connection

A licensed gas fitter runs and connects the natural gas supply, or the LPG connection if you are off mains gas. The Guardian units convert between natural gas and LPG without special tooling, which keeps options open if your fuel situation changes. Gas work is certified separately from the electrical work, and both certificates end up in your handover pack.

4. The automatic transfer switch at your switchboard

This is the heart of the system and the reason the install is electrician led. The automatic transfer switch (ATS) sits at your switchboard, watches the grid supply, and when it fails, starts the generator and physically switches your selected circuits from grid to generator. When the grid returns, it switches back and shuts the unit down.

The ATS is also what makes the setup legal and safe. It makes it impossible for your generator to backfeed into the street and endanger the lineworkers repairing the outage, and the whole arrangement is installed to AS/NZS 3000 and your network's requirements, whether you are in Ausgrid or Endeavour Energy territory. Not sure which network you are on? Check your network area in seconds with our postcode checker. Because the work happens at the switchboard and touches the supply side of your installation, it belongs with a Level 2 electrician, and occasionally reveals an old board that needs an upgrade first, covered in switchboard upgrades for generators.

5. Essential circuits or whole home

With the ATS in, we wire the circuits you chose to back up. Most homes protect the essentials: fridge, lights, some power, internet, medical equipment where relevant. Larger units can carry close to everything; whether that is worth paying for is exactly the question answered in can a generator power the whole house.

6. Commissioning: the simulated blackout

No Generac install is finished until it has been proven. We isolate the grid supply and watch the system do its job for real: sense the outage, crank, stabilise and transfer, with your backed up circuits alive within that 45 to 75 second window. We then restore the grid and confirm the switch back and shutdown. You see the whole cycle before we leave, alongside a walkthrough of the unit, its weekly self test and the paperwork, including the CCEW for the electrical work.

7. Afterwards: servicing and the warranty

Guardian units carry a 5 year limited warranty, and like any engine they need scheduled servicing to stay covered and reliable. Our Generac maintenance service handles the schedule for you, which matters most in the season you bought the thing for; a generator that has sat unserviced through winter is a gamble in a February storm.

How High Demand Electrical helps

We handle the whole chain in house: load assessment, supply of the Generac Guardian range, coordination of the gas fitter, the ATS and switchboard work as Level 2 ASPs, commissioning, compliance paperwork and ongoing servicing. One contractor, one point of responsibility, and a system proven working before we drive away. If you are still weighing up standby power against other options, start with standby versus portable generators.

Generac Installation FAQs (Sydney)

How long does the installation take?

It depends on the site: the gas run, the cable route and the state of your switchboard drive the timeline more than the generator itself. Your quote confirms the expected duration after the site assessment, and most standard installs are measured in days from delivery to commissioning, not weeks.

Can it really run the whole house?

The 20 kVA unit can carry most homes if the loads are managed sensibly, but whole home backup costs more in both unit and installation. Most families find essential circuits cover 90 per cent of what they miss in a blackout. See our whole house guide.

Does the generator need council approval?

Not always, but siting, noise and property type can trigger it. We flag this at quote stage so there are no surprises; the detail is in our council approval guide.

What happens if the blackout lasts days?

On natural gas the unit keeps running as long as the gas network does, which is the quiet advantage of mains gas over stored fuel. On LPG, runtime depends on your bottle capacity, which we size with you during planning.

Ready for a blackout proof home?

Get a Generac installation quote or call 0402 559 777. Every installation starts with an on site load assessment so the model, scope and pricing are confirmed before anything is ordered.