Field notes
Generator and Transfer Switch Install: The Permit and Inspection Checklist
Whole-home generator installs are profitable jobs that fail inspection more often than any other category in residential electrical. The reason is simple: a generator install touches electrical, gas, mechanical, and structural — and the AHJ inspector checks all of it.
Here is the per-jurisdiction permit and inspection checklist that keeps your install from failing the rough-in.
The four permits a typical generator install requires
Electrical permit. Covers the transfer switch, the generator disconnect, the load center modifications, and the bonding.
Gas permit. Required if the generator runs on natural gas or propane. Usually pulled by the plumber or the gas fitter, not the electrician — but you need to coordinate.
Mechanical permit. Some jurisdictions require this for the generator itself, especially when it sits on a pre-fabricated pad with a code-required clearance from the structure.
Structural or building permit. May be required if the generator pad requires a poured slab or if the install crosses an HOA setback.
The five inspection failures that kill generator install schedules
Failure 1: Wrong transfer switch configuration
Service-entrance rated vs non-service-entrance rated transfer switches are wired differently. Inspectors check this first. If the switch is non-SE-rated and the install treats it as SE-rated (or vice versa), the inspection fails. Pull the spec sheet for the switch before the install and confirm.
Failure 2: Improper grounding and bonding
The generator itself needs its own ground reference. The transfer switch creates a separately derived system in most configurations. The bonding has to be correct or the inspection fails. NEC 250 governs.
Failure 3: Inadequate clearance from structure
Manufacturer spec sheets give minimum clearance. Local AHJ often requires more. Verify both before the pad is poured.
Failure 4: Missing or improperly sized disconnect
The generator needs a code-compliant disconnect within sight of the unit. Size, type, and location all get inspected.
Failure 5: Conduit not rated for outdoor exposure
Sunlight-resistant PVC, weather-rated fittings, drip loops — small details, big inspection issue.
The pre-install permit checklist
Run this checklist before scheduling the install crew. If any item is missing, the install gets delayed, not failed.
1. Electrical permit pulled and posted on site
2. Gas permit pulled (or scheduled with the gas fitter)
3. Manufacturer-approved transfer switch on the truck
4. Pad poured and cured (if required)
5. Clearance from structure verified against both manufacturer spec and AHJ requirement
6. Service-entrance configuration confirmed
7. Bonding/grounding plan documented
8. Inspector contact info and scheduling availability confirmed
The post-install inspection checklist
Walk the installation before calling the inspector. Most failed inspections could have been caught by the foreman.
1. All conduit secured per code intervals
2. All connections torqued to spec (and labeled)
3. Disconnect within sight, properly sized
4. Grounding electrode conductor properly terminated
5. Transfer switch labeled correctly
6. Generator commissioning report ready for inspector
7. Load test performed and documented
How FieldCommand handles generator install workflow
FieldCommand ships with a generator install workflow template that tracks all four permits, both checklists, and the multi-trade coordination with the plumber/gas fitter. The foreman sees the pre-install checklist on their phone before the install date. The post-install checklist fires automatically and feeds the inspector call.