What a standby generator permit actually requires

A standby generator is a simple product to explain to a homeowner. The power goes out, the generator starts, the lights come back on, and the neighbors stand in their driveways looking envious.

The permit is a different conversation. A permanently installed generator sits outside the house, burns gas, ties into the electrical service, and makes noise next to a property line. That means it can draw review from the electrical inspector, the gas or mechanical inspector, the zoning desk, and in some places a structural or flood reviewer as well.

Here is what a residential standby generator permit usually has to cover, using four jurisdictions' published requirements to show how much the answer varies.

How many permits it takes

This is the first thing to settle, because it decides who files and who gets inspected.

• Houston requires an electrical permit pulled by a licensed electrical contractor and a plumbing permit pulled by a licensed plumbing contractor. Each contractor is responsible for their own permits and inspections.
• Troy, Michigan requires three: a building permit for zoning review of the placement, an electrical permit for the transfer switch and feeders, and a mechanical permit for the gas work.
• Placer County, California handles it as a building permit with a submittal that covers both the electrical and the propane or gas piping.
• Miami-Dade County files it with an electrical fee sheet, and the plans must be signed and sealed by a design professional.

Filing one permit in a city that wants three is a common reason a generator application stops before anyone looks at the plans. If the gas side needs a separately licensed contractor, that contractor needs to be lined up before filing, not after.

The site plan carries most of the weight

Nearly every generator checklist starts with a site plan, because placement is where the code and the zoning rules both bite. Expect to show:

• The generator location, with dimensions to the house and the property lines
• The location of the electrical panel and the transfer switch
• The gas meter, or the propane tank and its separation distances
• Doors, windows and other openings near the unit

The distances that come up most often:

• Building openings. Placer County requires a 5-foot setback from all building openings, citing NFPA 37. Houston and Troy both state a 5-foot minimum from windows and doors as well.
• Property lines. Houston requires at least 2 feet. Troy requires at least 6 feet, and only in side or rear yards. Miami-Dade requires 5 feet at the rear, 3 feet on an interior side in residential districts, and keeps generators behind the front building line.
• Combustible walls. Houston requires 5 feet from combustible exterior walls, which includes wood framing and brick veneer.

Those numbers do not agree with each other, which is the point. The spot the homeowner picked because it is out of sight may be the one spot on the lot that does not work.

Electrical documentation

The electrical side is where reviewers want the most detail. Placer County's checklist is a good example of a full request:

• A single-line diagram with conductor sizes and conduit or raceway
• Generator make, model and output
• Transfer switch details and location
• A load calculation showing the backup loads do not exceed the generator's capacity

The load calculation matters because of how the transfer switch is set up. Placer's checklist states that automatic transfer equipment must be able to supply the full load that is transferred, or the system must be designed with load management. A whole-house transfer switch on a generator that cannot carry the whole house needs load management shown on the plans, or the reviewer will ask about it.

Smaller items that still cause corrections:

• A disconnect that is lockable in the open position (Placer)
• A sign at the service entrance identifying the standby source and its location (Placer)
• Gas pipe bonding and identification of the transfer switching as separately or not separately derived (Miami-Dade)

Gas supply and the utility

A natural gas generator adds a large appliance to a gas service that was sized for the house as it was. The jurisdiction will want the gas side documented: Troy asks for the gas line size, type and length, Placer asks for a piping diagram for propane, and Houston's plumbing inspection checks pipe sizing from the meter, the flex connector, and the regulator.

The part that is easy to miss is the utility. Nicor Gas, for example, asks customers adding new gas appliances to submit a service revision request with the appliance BTU ratings, so the service line and meter can be sized properly, and quotes any charges in a proposal. Consumers Energy's residential scoping form has a line for natural gas generators and states that if the home's gas consumption requires a larger capacity meter, the customer needs to call to arrange it.

That request runs on the utility's schedule, not the building department's. It is worth starting when the job is sold.

Structural, flood and noise

These depend heavily on location:

• Pad and anchoring. Miami-Dade asks for soil bearing capacity, pad size, thickness and reinforcement, and an anchoring detail.
• Flood zones. Miami-Dade requires residential generators to be at or above the base flood elevation.
• Screening and height. Miami-Dade caps generator height at 5 feet above grade and requires screening from view by a wall or hedge in residential districts.
• Noise. Troy allows a maximum of 65 decibels measured at the property line. Houston states that generator approval does not exempt the installation from the city's noise ordinance.

The inspection sequence

Generator inspections often start earlier than people expect. Houston's electrical inspection includes the pad location before the concrete is poured. Troy lists an electrical rough and final, a mechanical pressure test and final connection, and a building final after all trades are complete.

Missing the pre-pour inspection is an expensive way to learn about it. So is scheduling a building final before the gas and electrical finals have passed.

Where generator permits actually stall

In practice, the problems cluster in a handful of places:

1. Wrong permit count. One application filed where the jurisdiction wants separate electrical, gas and zoning permits, or separately licensed contractors.
2. Placement. A unit drawn too close to a window, a property line or a combustible wall.
3. Load calculation. A transfer switch the generator cannot fully carry, with no load management shown.
4. Gas capacity. A meter or service that needs upsizing, discovered after the generator is on site.
5. Inspection order. A missed pad inspection, or finals scheduled out of sequence.

Most of these can be caught at the site visit. A photo of the proposed location with the nearest window and property line in frame, a panel photo, and a gas meter photo answer most of the questions a reviewer is going to ask.

How TaskHatch helps

We file standby generator permits as part of our flat-fee residential scope, starting at $150 per project, with plan check comments included. If the jurisdiction needs revised plans or new documents from you, that resubmittal is $75. Inspection coordination is $100 per project and covers every inspection through final, including the trade finals that have to pass before the building final.

Sources

• Placer County, Residential Generator Checklist
• Miami-Dade County, Checklist for Permanent Installation of Generators
• Houston Permitting Center, Residential Standby Generator requirements
• City of Troy, Michigan, Requirements for Generator Permits and Inspections
• Nicor Gas, Meter Service Revision Request
• Consumers Energy, Residential Scoping Document (Form 1481)