Standby Generator Installation: The Process
Updated 2026-08-16 · 6 min read
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The physical work is short. The project is not, and knowing which stage you're in prevents a lot of unnecessary concern.
1. Site survey and design
An installer visits to determine:
- Generator location — clearances from the building, windows, and property lines
- Distance to the electrical panel and to the gas source
- Fuel supply capacity — is the existing gas meter and line adequate?
- Load calculation, which sizes the generator
- Transfer switch type — service-rated or subpanel, load management or not
Ask to see the load calculation. Sizing determines everything downstream, and oversizing cascades into a bigger gas supply and higher running cost. Cross-check with the generator sizing calculator.
This is also when the gas supply question should be settled. It's the most common source of both cost surprises and delays — see standby generator installation cost.
What permits does a standby generator need?
Typically several:
- Electrical, for the transfer switch and feeders
- Gas or plumbing, for the fuel line
- Building, sometimes, for the pad
- Zoning, occasionally, for placement and noise setbacks
Issuance ranges from days to weeks depending on jurisdiction. The licensed contractor should pull them.
See generator permits and inspection.
Does the gas utility need to be involved?
If the meter needs upsizing, this becomes the critical path.
The utility surveys, schedules, and performs the work on their timeline. It's outside the installer's control and it can add weeks.
For propane installations, this stage is instead tank delivery and placement, which is usually faster and coordinated with your supplier.
4. Site preparation
The pad. Poured concrete needs forming, pouring, and curing time — typically several days before the generator can sit on it. Composite pads install immediately, which is one reason they're common.
Trenching, for gas line and electrical conduit between the generator, the meter, and the panel. Route matters: crossing a finished lawn or a driveway costs more and needs restoration.
Access. The generator is heavy. Getting it to the pad may require equipment.
See generator pad and mounting.
5. Installation
Typically one to three days:
The generator is set on the pad and anchored.
Gas line run and connected, then pressure-tested.
The transfer switch installed — this is where your power goes off, usually for a few hours. Much shorter than a panel replacement, since the existing panel generally stays.
Feeders and control wiring run between the generator, transfer switch, and panel.
Grounding and bonding configured — including the neutral bonding decision, which must match the transfer switch type. See generator neutral bonding.
Battery installed and connected.
What is inspected on a standby generator?
Separate inspections for electrical and gas, sometimes on different days.
Common findings: grounding and bonding, clearances from windows and openings, gas line support and testing, and working clearance around the transfer switch.
If something fails, the installer corrects and re-inspects. Normal, not a crisis.
7. Commissioning
The stage that proves the system works. It should include:
- Controller configuration — sensing delays, transfer timing
- Exercise schedule set to a sensible day and hour, so the weekly self-test doesn't annoy you or the neighbours
- Transfer test under load — simulate an outage and confirm the generator starts, transfers, and carries the house
- Voltage and frequency verification
- Return transfer and cooldown confirmed
- Load management configuration, if fitted
- Walkthrough — you should be shown the controller, the manual transfer procedure, the fuel shutoff, and the maintenance schedule
Don't skip the walkthrough. The system runs itself, but you need to know how to read the controller and what to do if it faults.
How long does standby generator installation take?
| Stage | Typical duration |
|---|---|
| Survey and quote | Days |
| Permits | Days to weeks |
| Gas utility work (if needed) | Weeks |
| Pad and site prep | 1–5 days incl. curing |
| Installation | 1–3 days |
| Inspection | Days |
| Commissioning | Hours |
Several weeks end to end is normal. If the gas meter needs upsizing, longer.
Book in the off-season. Installers are busiest immediately after a major regional outage, and so is everyone else.
What should you ask a generator installer?
- Is the gas supply adequate, or is meter upsizing expected?
- Where exactly will the generator sit, and what clearances apply?
- How long will power be off during transfer switch installation?
- What's the trenching route, and is restoration included?
- Who pulls the permits?
- Is commissioning with a load test included?
- What does annual service cost, and is it required for warranty?
Where to go next
More in our generator and backup power guides.
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