There are two main types of generators: permanently installed, standby generators; and gasoline-powered, portable generators.
Standby generators typically operate on natural gas or liquid propane. They remain fixed in place outside the home and are designed to supply on-site power to specified circuits through a home's electrical wiring. These generators work in tandem with a manual or automatic transfer switch, which automatically detects an interruption in grid-powered electricity and subsequently transfers over electrical input to the generator.
The transfer switch suspends input from the generator once it senses that utility-powered electricity has resumed. Generators for small- to medium-size homes are typically air-cooled and employ fans to regulate the temperature inside the unit. Liquid-cooled units are used for the larger energy loads in larger homes.
- They may be turned on manually, or they may be programmed to switch on automatically in the case of a power outage even when no one is home.
- Power may be supplied for extended periods of time.
- Hard-wired systems, such as a home's furnace, well pump and air conditioner, may maintain continuous power.
- Uninterrupted power can be supplied to systems that must remain on continuously, such as medical equipment used for breathing, etc.
- Installation may require a permit.
- A qualified technician, such as an electrician, is required to install the ATS and to determine the electrical load requirements for the circuits in a home.
- Routine maintenance is required.
- Standby generators may be prohibitively expensive.
Advantages to portable generators are as follows:
- Portable generators are versatile. They may be used at home or transported and utilized in remote locations, such as a campground or a construction site.
- They do not require complicated installation.
- They typically do not require permits.
- Portable units are generally less expensive than standby generators.
- Devices that are hard-wired into a home's electrical system cannot be powered by a portable generator if no transfer switch is installed.
- Portable and standby generators produce dangerous carbon monoxide (CO) gas, which can be deadly if inhaled.
- Inexperienced installers are exposed to the risk of electrical shock. Only qualified electricians should attempt to install a generator.
- Overloading a generator may result in reduced fuel efficiency, damage to appliances or fire.
- Standby generators or their required transfer switches that are incorrectly wired (or missing) may result in "back-feed" -- a hazardous condition in which an electrical current is fed back into the grid -- which could potentially electrocute and kill homeowners, utility workers, and others who are using the same utility transformer.
- Connecting a portable generator directly into a home's wall outlet can also cause dangerous back-feed.
- Generators that are exposed to water or that are not properly grounded can cause electrocution.
- Gasoline for portable generators is highly flammable and may cause a fire when exposed to an open flame or when spilled on the hot generator.
- Over-taxed cords attached to a portable generator may cause a fire.
InsideOut inspectors check for the following:
- Generators should never be used anywhere indoors, even if the area is ventilated.
- Portable generators placed outside should not be near doors, vents or open windows leading into the home.
- Carbon-monoxide detectors should be installed in case CO is accidentally released into the home.
- A standby generator hard-wired into a home should have a transfer switch installed to prevent backfeeding. An inspector can locate this device situated between
- Generators should be properly grounded.
- Units should be dry and shielded from contact with liquid.
- Only heavy-duty electrical cords that are rated for outdoor use should be plugged into portable generators.
- Electrical cords should not have any punctures or exposed wiring.
- Cords running from portable generators should be kept out of the way of foot traffic and should not run underneath rugs.
- The total electrical capacity of the generator should exceed the power requirements of the devices that the unit is supplying.
- Fuel for portable generators should be stored away from the home and children in clearly labeled and durable containers.
In summary, generators can be lifesavers during a power outage, but they present serious health and safety concerns if they are not installed and used properly.