Generator changeover switches
If you're on a rural feeder, you already know outages here last longer than they do in the suburbs. A changeover switch is how you run the house safely on a generator.
Why you can't just plug a generator in
Running a generator into a powerpoint — sometimes called a suicide lead, and the name is accurate — backfeeds your installation. It puts live power onto wiring that linesmen may be working on, it bypasses your protection, and it's genuinely dangerous.
A changeover switch physically prevents the generator and the grid from ever being connected at the same time. It's a mechanical interlock, not a setting, and it's the only correct way to do this.
Manual or automatic?
| Manual changeover | Automatic transfer switch | |
|---|---|---|
| How it switches | You throw a switch when the power goes out | Detects the outage and switches itself |
| You need to be home | Yes | No |
| Generator starting | You start it manually | Auto-start generator required |
| Typical use | Most households, occasional outages | Properties with pumps, stock, medical equipment or long absences |
| Cost | Lower | Higher — more switchgear and a compatible generator |
Which circuits to back up
The point that catches people out is that you don't back up the whole house. A domestic generator cannot run everything, so the design work is choosing what matters:
- Water pump — on tank or bore supply, no power means no water at all
- Fridge and freezer — the thing that actually costs money in a long outage
- Lighting, at least in the main living areas
- Internet and comms — increasingly the difference between working and not
- Septic or sewage pump where fitted
- Gate motor, if you'd otherwise be locked in
Air conditioning and electric hot water are usually left off — they'll swamp a domestic generator on their own.
Generator changeover questions
What size generator do I need?
That follows from which circuits you back up, not the other way round. Work out what must keep running, add up the load including motor starting current for pumps, and size from there. We'll do that calculation with you before you buy anything.
Is a changeover switch a legal requirement?
If you're connecting a generator to your house wiring, yes — it must be through a compliant changeover arrangement that prevents backfeed. There's no compliant way to do it with an extension lead.
Can I add one to my existing switchboard?
Usually. It needs space and a sensible arrangement of the circuits you're backing up, which sometimes means reorganising the board. We'll tell you when we look at it.
Should I get a battery instead?
They solve overlapping problems. A battery is silent, automatic and handles short outages beautifully. A generator runs indefinitely as long as you keep feeding it fuel, which matters in a multi-day outage. On acreage, plenty of people end up with both.
What customers say
Jason onsite quickly and completed the work on the spot, giving us a good price and was very polite. Would highly recommend.
Jason solved a really complex problem for our house with excellent professionalism and workmanship. Highly recommend, would def work with him again. On time delivery and within budget.
Fantastic service! Friendly, efficient and well priced. Highly recommend. Thank you for swiftly fixing our switches.
These are Google reviews for our team at Cync Electrical & Automation — the licensed contractor behind Hills Electrician. 5.0 from 20 reviews. — see the profile
Sick of losing power?
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