Backup Generators: The Complete Walkthrough
This guide covers backup generators, rated an easy to moderate task, typically taking setup: a few hours.
Our printable card on backup generators covers the essentials at a glance — here's the fuller walkthrough.
Sized to your actual critical loads
A generator sized to run everything at once is usually overkill and expensive — most homesteads do better sizing to the genuinely critical loads (fridge, freezer, some lighting, water pump) rather than the whole property at once.
What You'll Need
A few things matter most here:
- A generator sized to your critical load list, with some margin
- Appropriate fuel storage (petrol, diesel, or LPG depending on generator type)
- A transfer switch if connecting to household wiring (essential for safety)
- Regular maintenance supplies (oil, filters, spark plugs as applicable)
The Method
The key things to get right:
- 1. List your genuinely critical loads and their combined running (not just starting) wattage.
- 2. Choose a generator sized with reasonable margin above that critical load total.
- 3. Install a proper transfer switch if connecting to household circuits — never back-feed through a wall socket, which is dangerous to utility workers and illegal.
- 4. Store fuel safely and rotate stock so it doesn't degrade.
- 5. Run and test the generator periodically, not just when an outage occurs — a generator that hasn't run in months may fail exactly when needed.
When Things Go Wrong
A few things matter most here:
- Won't start after sitting unused — stale fuel is the most common cause; use a fuel stabiliser or rotate fuel stock, and run the generator periodically.
- Overloaded and tripping — recalculate actual running wattage of connected loads, including motor starting surge for things like fridges and pumps.
- Unsafe back-feeding into household wiring — always use a proper transfer switch, never a workaround; this is a genuine safety hazard.
- Excessive fuel use — running a large generator for a small load is inefficient; match generator size to actual need, or consider a smaller unit for baseline loads.
Ongoing Timing
Best time — set up and test before you need it, ideally right after purchase, not during your first outage. Duration — modern generators can run continuously for many hours per fuel tank, refuelled as needed. Maintenance — regular test runs, oil changes per manufacturer schedule, and fuel stock rotation. Signs of success — starts reliably on the first or second pull/attempt, and runs your critical loads without tripping or overloading.
That's the full walkthrough. The printable A4 quick-reference card for this is on the main guide page below.