Reference

Standby-generator glossary

Plain-English definitions for the terms that show up in generator quotes, load calculations, and transfer-switch scopes.

24 entries with cross-references and entity links.

Reference glossary for standby-generator terminology — sizing terms like load calculation and startup surge, the transfer switch and back-feed, natural gas versus propane, carbon-monoxide safety, the exercise cycle, and Louisiana permit and licensing terms, with links to authoritative sources where applicable. Useful when comparing generator quotes that use unfamiliar technical language, or when reading a scope before you sign.

Automatic transfer switch (ATS): The device at the heart of a standby system. It senses the loss of utility power, disconnects the home from the grid, and connects it to the generator automatically, then reverses the process when utility power returns. The disconnect from the utility is what prevents dangerous back-feed onto the line. It operates without the homeowner touching anything.

Back-feed: The dangerous condition where a generator sends power backward onto the utility line — typically caused by plugging a portable generator into a wall outlet without a transfer switch. Back-feed can electrocute a lineman working to restore power and can damage the home’s wiring. Preventing it is the entire safety purpose of a transfer switch or interlock.
Battery (starting): The battery that cranks a standby generator’s engine to start it. It is charged by the exercise cycle and is one of the first things to fail on a neglected unit — a dead starting battery is among the most common reasons a generator will not start during an outage. Routine testing and replacement are part of maintenance.

Carbon monoxide (CO): A colorless, odorless, poisonous gas produced when fuel burns. Portable generators emit it, which is why they must never run in a garage, carport, basement, or against the house — even with a door open. Carbon-monoxide poisoning during power outages is a documented, recurring cause of death after storms. Standby units live outdoors and are wired in, removing this in-the-garage risk.
Clearance (siting): The minimum distances a generator must be set from doors, windows, vents, and combustibles, per the manufacturer and local code, so exhaust disperses safely and the unit can be serviced. Proper siting is part of a code-compliant standby install and is verified at the assessment stage.

Essential-circuit backup: A standby (or portable) configuration that powers only selected circuits — typically the refrigerator, a well or sump pump, some lights and outlets, and often one air-conditioning zone — through a smaller, less expensive generator and a transfer switch wired to just those circuits. Frequently the more cost-effective answer for a home that loses power for days.
Exercise cycle: A short, scheduled self-test in which a standby generator starts itself and runs briefly — commonly weekly or biweekly — to keep the engine lubricated and the battery charged so it is ready when an outage comes. A unit whose exercise cycle was never set, or that nobody checks, can sit dead for months until the power goes out.
Electrical permit: The authorization, issued by the local jurisdiction, required before generator and transfer-switch work begins, followed by an inspection. The permit and inspection are what confirm the install — especially the back-feed protection — was done to code, and they protect the homeowner if anything goes wrong. A gas hookup adds its own permitting.

Generator interlock: A mechanical device added to an electrical panel that lets a portable generator safely power circuits through the panel by preventing the main breaker and the generator breaker from being on at the same time. It is a lower-cost, code-compliant alternative to a separate transfer switch for portable-generator backup, when properly installed.
Gas-line capacity: Whether an existing natural-gas line can deliver enough pressure and volume to feed a generator at full load. A line sized for a stove and water heater may fall short for a whole-home generator. Verifying capacity — and upgrading the line if needed — is part of a proper natural-gas standby install.
Generator maintenance: Routine service — oil and filter changes, spark plugs, and battery testing — plus a check of the exercise cycle and transfer switch, that keeps a standby generator able to start when the grid drops. The most common reasons a neglected unit fails to crank are a dead battery and overdue oil. Maintenance is the difference between a real backup and an expensive lawn ornament.
Generator pad: The level, stable base — commonly a concrete or composite pad — a standby generator is set on, positioned to the manufacturer’s required clearance from doors, windows, and combustible materials. In flood-prone bayou areas the pad placement and elevation also factor into keeping the unit out of standing water.

Kilowatt (kW): The unit of power a generator’s capacity is rated in. The required kW comes from the load calculation — the running load of the circuits being backed up plus the startup surge of their motors. A whole-home unit carries a higher kW rating than an essential-circuit unit. Sizing is matched to the home, not to a generic rule of thumb.

Load calculation: The engineering process of adding up everything a home needs the generator to run — the air-conditioner, water heater, well or sump pump, refrigerator, lights, and outlets — including the brief startup surge of motors, to determine the correct generator size. Sizing from a real load calculation, rather than a round number off square footage, is what keeps the unit from tripping on startup or being oversized.
Load management (load shedding): Smart control, usually built into the transfer switch, that lets a smaller generator run a larger home by temporarily dropping lower-priority loads when a big motor starts. It avoids oversizing the unit to cover everything running at once, lowering the generator size and cost while still carrying the priority circuits.
Louisiana State Licensing Board for Contractors: The Louisiana state agency that licenses and regulates contractors, including the electrical work involved in standby-generator and transfer-switch installation. Generator installs in the state are done by appropriately licensed electricians under a local electrical permit and inspection. A license can be verified with the board before hiring.

Manual transfer switch: A transfer switch the homeowner operates by hand, commonly paired with a portable generator. It safely isolates selected circuits from the utility before connecting them to the generator, preventing back-feed. The difference from an automatic switch is that the changeover is not hands-off — you start the generator and throw the switch yourself.

Natural gas (NG): A gaseous fuel delivered by the utility line, a common fuel for standby generators because there is no tank to refill and no runtime limit from fuel storage. The catch is that the existing gas line must have the pressure and pipe capacity to feed the generator under full load, which a proper install verifies before promising natural gas.

Portable generator: A movable, engine-driven generator, usually gasoline-powered, used for temporary backup. It must be run outdoors well away from the home because it emits carbon monoxide, and it should connect to a home’s wiring only through a manual transfer switch or interlock — never plugged into a wall outlet. Often the right, lower-cost choice for short outages and a few essential loads.
Propane (LP): Liquefied petroleum gas stored in a tank, used to fuel standby generators where there is no natural-gas line. It stores energy densely and keeps well for long periods, suiting homes that lose power rarely but for days. Runtime is limited by tank size, so the tank is matched to the outage length the homeowner wants to cover.

Standby generator: A permanently installed backup power system wired into a home’s electrical panel that starts automatically when utility power fails and shuts down when it returns. It runs on an external fuel supply — natural gas or propane — rather than gasoline carried in by hand, so it can run for as long as the fuel lasts. Distinct from a portable generator, which is rolled out and refueled manually.
Starting (surge) load: The momentary spike in power an electric motor draws at startup — several times its normal running wattage — before settling to steady-state. The air-conditioner compressor, well pump, and sump pump are the big offenders. A generator sized only for running wattage will trip when one of these motors kicks on, which is why surge is central to honest sizing.

Transfer switch rating: The current (in amps) and number of circuits a transfer switch is built to handle, matched to the generator and the loads it serves. A whole-home switch carries the full panel; an essential-circuit switch serves only the selected circuits. The rating has to suit the install, which is set at the load-calculation and quote stage.

Whole-home backup: A standby configuration that powers the entire electrical panel, central air included, requiring a larger generator. It removes the need to choose which circuits matter, at a higher equipment and install cost than essential-circuit backup. The right call when the budget supports keeping the full house running through a multi-day outage.

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