PCARES - Generators

PCARES

Types by Technology (Power Output)

Conventional (Standard) Portable Generators:
- How they work: Use a direct engine-to-alternator connection to produce AC power.
- Best for: Job sites, heavy-duty power tools, and high-wattage home backup.
- Pros/Cons: High power output (often 3,000 to 12,500+ watts), but louder (72–80 dB) and produces "dirty power" (higher Total Harmonic Distortion) that can risk sensitive electronics.
Inverter Generators:
- How they work: Produce AC power, convert it to DC, and then invert it back into clean, stable AC power.
- Best for: Camping, RVs, tailgating, and running sensitive electronics like laptops, TVs, and medical devices (under 3% THD).
- Pros/Cons: Very quiet (often 50–60 dB), fuel-efficient, and lightweight, though typically more expensive per watt.
Solar / Battery Portable Power Stations:
- How they work: Store electricity in internal lithium-ion/LiFePO4 batteries charged via solar panels, wall outlets, or car ports.
- Best for: Indoor use, quiet outdoor recreation, and light emergency charging.
- Pros/Cons: Silent, zero emissions, and safe to use indoors, but lower power output and limited battery capacity compared to fuel engines.

Types by Fuel Source

Gasoline Generators:
- Most common and easiest to find, offering high immediate output, though gasoline has a short storage shelf life (3 months to 3 years with stabilizer) and can gum up carburetors if left sitting.
Propane (LPG) Generators:
- Burns cleaner with lower emissions, produces less carburetor gunk, and propane tanks store indefinitely without degrading.
Dual-Fuel Generators:
- Can run on either gasoline or liquid propane, letting you switch based on availability or convenience (such as the Westinghouse Dual Fuel Generator).
Tri-Fuel Generators:
- Capable of running on gasoline, propane, or natural gas (which can hook directly into a home natural gas line for near-limitless runtime during long outages, such as the Westinghouse Tri-Fuel Generator

What Should I Know About Clearance Requirements When Installing a Generator?

Always check with AHJ for local codes as those will supersede these recommendations.
Do NOT install a home generator under a wooden deck or platform.
Units that do not feature the SwRI logo must be installed 5 ft. from combustible materials and 3 ft. from non-combustible materials.

Permits are required when installing a permanently mounted whole-house or standby home generator in Placer County.

Types of Permits Needed for Standby Generators

A permanent home backup generator installation typically requires multiple reviews and permits through Placer County Building Services

Generator Checklist for Placer County 2019 CALIFORNIA BUILDING STANDARDS CODE OF REGULATIONS TITLE 24

Home Standby Generator Clearance Requirements

Clearance requirements ensure the generator is operated at a safe distance where heat and fumes will not cause fires or health hazards. The exhaust gets extremely hot and remains hot after shutdown. Flammable material may ignite and burn from the heat of the exhaust system.

NFPA 37 Overview

The National Fire Protection Association’s standard for the installation and use of stationary generators.
Its requirements limit the spacing of the generator from a structure or wall.
The unit must be located where it’s readily accessible for maintenance, repair, and first responders.
Minimum clearance requirements are for adequate airflow, maintenance, and safety.

NFPA 37 Requirements

5ft. from openings in walls (operable windows, doors, vents, window wells, or openings in the wall).
18 in. of clearance from the back of the generator to a stationary wall or building (based on testing done by the Southwest Research Institute or SwRI).
5 ft. of clearance above the generator.
3 ft. of clearance at the front and both ends. This includes trees, shrubs, and bushes. Vegetation not in compliance could obstruct airflow and exhaust fumes could inhibit plant growth.
In addition to these requirements, verify all potential for water intrusion is directed away from the generator enclosure: sprinklers, roof run-off, down spouts, and sump pump discharge.

Protect the structure

Verify the structure itself as correctly caulked and sealed to prevent air from leaking in or out. Voids, cracks, or openings around windows, doors, soffits, pipes, and vents can allow exhaust gas to be drawn into the structure. Some examples of entry points are described and included in, but not limited to, the accompanying table.

Transfer Switches

Transfer switches whether manual or automatic, allow you to choose between utility power or backup generator power
Transfer switches are the only way to safely power your home’s electrical system
Using a transfer switch prevents backfeeding. This occurs when your generator becomes a power source for the surrounding area and can damage your home, your neighbor’s home, and injure workers trying to restore power

Portable Generators

Location

- Always keep generators at least 20 feet away from your home
- Never operate a generator in an enclosed space
- Make sure the generator has 3-4 feet of clear space above and on all sides for proper ventilation
- Keep generators away from door, windows, and vents
- Always direct exhaust away from your home

Use

- Always use grounded cords and inspect cords for damage prior to use
- Use the proper cord for the wattage being used
- Always use GFCI protection
- Make sure to start/stop the generator when no electrical loads are connected
- Keep generators dry, do not operate when wet, and refuel when cool
- Do not overload generators
- Do not plug a generator directly into your home, connect items being powered directly to the generator

Inverter generators

Inverter generators produce clean, stable power with low harmonic distortion, making them safe for sensitive electronics like laptops and phones, but they still pose severe safety risks—such as carbon monoxide poisoning, fire, and electrical shock—if not operated properly.

Carbon Monoxide (CO) Safety

Never use indoors: Never run an inverter generator inside a house, garage, basement, crawl space, or shed, even with doors or windows open.
Keep distance: Place the generator strictly outdoors at least 20 feet away from doors, windows, and air vents, with the exhaust pointing away from living areas.
CO sensors: Many modern models include built-in automatic shutoff sensors (like WEN Watchdog or CO Alert) that trigger if carbon monoxide builds up nearby, though this is a backup layer and does not replace proper outdoor placement. Always install battery-operated carbon monoxide alarms inside your home.

Electrical and Load Safety

Clean power output: Inverter generators produce a pure sine wave with very low total harmonic distortion, making them safe for TVs, routers, medical devices, and computers that can be damaged by "dirty" power from standard open-frame generators.
Avoid direct wiring backfeed: Never plug a portable inverter generator directly into a standard wall outlet or your home's main electrical panel (backfeeding), which can electrocute utility workers. To power home circuits safely, use a proper transfer switch or interlock kit installed by a licensed electrician.
Use rated extension cords: Plug appliances directly into the generator using heavy-duty, outdoor-rated 3-prong extension cords.
Prevent overloading: Respect the generator's continuous and peak wattage limits to avoid overload shutdowns. Check appliance requirements via the guidelines on Novus Power Equipment.

Weather, Fuel, and Maintenance

Keep it dry: Do not operate an inverter generator in the rain or wet conditions unless you use a specialized weatherproof running cover like the GenTent Generator Running Cover.
Refuel safely: Always shut off the engine and let the unit cool completely before adding fuel. Store gasoline or propane in approved safety containers outside of living spaces.
Routine checkups: Inspect oil levels, clean air filters, and service the engine per manufacturer recommendations (typically every 100 hours or before major use).

Solar generators

Solar generators are generally much safer than traditional gas-powered generators, primarily because they produce no carbon monoxide, require no flammable fuel storage, and operate quietly. However, they still carry specific electrical and battery safety considerations that require proper handling.

Key Safety Advantages Over Gas

No Carbon Monoxide: Gas generators emit toxic, odorless carbon monoxide gas and must be kept outdoors and far from windows. Solar generators produce zero emissions, making them safe for indoor use.
No Fuel Hazards: You do not need to store, transport, or spill gasoline or diesel, eliminating major fire and chemical risks.
Silent Operation: They run quietly, avoiding the constant engine noise that adds stress during blackouts.

Potential Risks and Safety Guidelines

Battery Chemistry and Fire Risks: Most modern solar generators use LiFePO4 (Lithium Iron Phosphate) batteries, which are thermally stable and highly resistant to thermal runaway or fire compared to older lithium-ion chemistries. Most units also feature built-in Battery Management Systems (BMS) to prevent overcharging, short-circuiting, and overheating.
Moisture and Water Exposure: Solar power stations and unsealed ports are not waterproof. Always keep the main unit dry, use them in covered or indoor areas during wet weather, and protect external cables and connectors.
Overloading Outlets and Inverters: Do not plug appliances that exceed the generator's running or peak wattage capacity. Check your device requirements (such as heavy-duty space heaters or refrigerators) before connecting multiple high-draw items.
Proper Ventilation: Even though solar generators don't emit fumes, the internal inverter and battery pack generate heat during heavy use or fast charging. Ensure the cooling vents are unobstructed and place the unit on a hard, flat surface.
Backfeed Safety (if integrating with home wiring): Unlike plug-in portable use, connecting any generator directly to a home's electrical panel requires a proper transfer switch installed by a licensed electrician to prevent dangerous backfeeding into utility lines.

Site selection and preparation

Potential CO entry points

Generator exhaust can enter a structure through large openings, such as windows and doors. However, exhaust and CO can also seep into the structure through smaller, less obvious openings.

Improper use and installation of generators could cause CO poisoning
Make sure your home has carbon monoxide alarms outside each sleeping area and on every level of the home
CO can kill in as little as 5 minutes
Symptoms of CO poisoning
- Dizziness
- Headaches
- Nausea
- Tiredness
If you experience CO poisoning systems, get fresh air, do not reenter areas, and call 911.

CO Levels

What are the exposure levels numbers. This is expressed in Parts Per Million (ppm). (1% of a gas equals 10,000 ppm)

Safe Levels:

0-9 ppm: Considered normal CO levels in air and poses no significant health risk for healthy individuals.
9 ppm: The World Health Organization (WHO) recommends an average of 9 ppm for indoor air exposure for 8 hours.

Dangerous Levels:

- 10-29 ppm: Prolonged exposure to these levels may cause chronic health problems like headaches and nausea.
- 30-35 ppm: Flu-like symptoms may begin to develop, especially in vulnerable populations.
- 50 ppm: OSHA (Occupational Safety and Health Administration) has a permissible exposure limit (PEL) of 50 ppm as an 8-hour time-weighted average (TWA).
- 100 ppm: Maritime workers must be removed from exposure if CO concentration exceeds 100 ppm.
- 200 ppm: Slight headache, fatigue, dizziness, and nausea may occur after 2-3 hours of exposure.
- 400 ppm: Frontal headaches may occur within 1-2 hours of exposure, and the condition can become life-threatening with prolonged exposure.
- 800 ppm: Dizziness, nausea, and convulsions may occur within 45 minutes, followed by unconsciousness within 2 hours and death within 2-3 hours.
- 12,800 ppm: Death may occur within 1-3 minutes.

So how does CO behave, to understand that you need to have a basic understanding of its chemical property, One of which is Specific Gravity (Sp).

The specific gravity of carbon monoxide (CO) is 0.9657 when compared to air, which is considered to have a specific gravity of 1. This means CO is slightly lighter than air. Due to its slightly lighter nature, CO may rise towards the ceiling if it's mixed with warm air from sources like combustion

The best place to mount a carbon monoxide (CO) detector is outside of each sleeping area or bedroom and on every level of your home, including the basement.

Key Placement Locations

Sleeping Areas: Install an alarm within 10 feet of every bedroom door, or directly inside bedrooms if doors are typically kept closed, ensuring the sound is loud enough to wake everyone up.
Every Floor: Put at least one detector on every level of the house, including the basement and attic spaces.
Near Attached Garages: Place a unit just inside the interior doorway that leads from your house to the attached garage (at least 10 feet away from the garage door) to catch vehicle or gas tool fumes early.
Fuel-Burning Appliances: Maintain a buffer of 15 to 20 feet away from gas stoves, fireplaces, furnaces, and water heaters to prevent nuisance false alarms from trace combustion.

Height and Mounting Guidelines

Wall vs. Ceiling: Carbon monoxide mixes uniformly with room air rather than rising strictly to the ceiling like smoke. Most manufacturers and safety organizations (such as the US EPA) recommend mounting them on the wall at roughly 5 feet above the floor (eye or chest height) or on the ceiling following the specific manufacturer's manual.
What to Avoid: Do not place detectors in dead air spaces, near heating or AC vents (within 36 inches), directly above or beside flame-producing appliances, or in high-humidity zones like bathrooms.

California law (Senate Bill 183, the Carbon Monoxide Poisoning Prevention Act) requires carbon monoxide (CO) detectors in all residential dwellings that have a fossil fuel-burning appliance, a fireplace, or an attached garage.

Where Detectors Are Required:

Outside each separate sleeping area in the immediate vicinity of the bedrooms.
On every level of the dwelling unit, including basements.
Inside bedrooms if a fuel-burning appliance is located within the bedroom or its attached bathroom (per local codes like LA County).

Here's a more detailed look at each type:

Portable Generators:
These are generally smaller, more lightweight, and can be moved easily from one location to another. They are often powered by gasoline or diesel and are suitable for powering tools, appliances, and even some electronics when a power source is needed.
Inverter Generators:
Inverter generators are known for producing cleaner, more stable power than traditional portable generators. They use an inverter to convert DC electricity to AC electricity, which is essential for powering sensitive electronic devices. They are often quieter and more fuel-efficient than portable generators.
Standby Generators:
Also known as whole-house generators or emergency generators, these generators are designed to provide power to an entire home during a power outage. They are typically larger and more powerful than portable or inverter generators. Standby generators often have an automatic transfer switch that connects the home's electrical system to the generator when power is lost.

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