Tag Archives: Electricity

What is an Arc Fault Circuit Interrupter?

An arc fault circuit interrupter, or AFCI, is designed to detect dangerous electrical arcs and disconnect power to the circuit before a fire starts.  They contain current and temperature sensors as well as a microprocessor that can distinguish arc faults caused by unintentional electrical hazards.

An arc fault is the unintentional flow of electricity between two separate wires.  This electrical discharge can create enough heat to further break down electrical insulation and start a fire, especially if nearby objects are flammable, such as a wooden floor, wall or piece of furniture.  For instance, an arcing fault might occur in a power cord that has been damaged (for example, crushed beneath a piece of furniture).  The damaged insulation could enable electricity to jump across to a neighboring wire within the cord and build up enough heat to start a fire. Arcing faults can also occur in power cords where the insulation has cracked due to age – or in electrical wires inside a wall that have been accidentally pierced by a nail.

According to the Electric Safety Foundation International, arcing faults are responsible for 30,000 home fires each year in the United States. These types of fires can be prevented by installing AFCIs. In new homes, AFCIs are now required in the living room, bedrooms and dining room.

There are three types of AFCIs.  The most common, a branch AFCI, replaces standard circuit breakers in your home’s service panel. Branch AFCIs can detect an arc-fault in the circuit from the panel to the outlet and thus will shut off electricity to that branch circuit. Outlet AFCIs provide arc-fault protection to devices plugged into that outlet.  Combination AFCIs are a more advanced technology that can detect additional kinds of faults, such as an arc within a single wire due to a loose connection.

Does your home have AFCIs?

You can check to see if your home has AFCIs by looking at the outlets and the circuit breakers.  An AFCI outlet and circuit breakers will be labeled as such and have a TEST button on them.  AFCIs are not to be confused with ground fault circuit interrupters (GFCIs), which also have a TEST button. GFCIs are another type of electrical safety device that detect current imbalances caused by a current leak, which can occur in the case of electric shock. They are required in bathrooms and kitchens and are often installed in other locations with water exposure, because moisture increases the risk of electric shock.

GFCIs protect people from electrical shock and AFCIs protect structures from fires.  If you have AFCIs installed, they can be tested by pushing the TEST button. If the circuit trips, then the AFCI is working.  To reset the AFCI, first turn the breaker to the OFF position. Then you will need to flip the breaker back to ON.  If the circuit does not trip, the AFCI should be replaced.  AFCIs can be installed by a licensed electrician and typically cost less than $50.

For more information about AFCIs and other electrical safety devices, visit the Electrical Safety Foundation International’s websitewww.esfi.org .

What’s a GFI outlet and where should I use them in the house?

A ground fault interrupter outlet, or GFI outlet, is designed to protect people from electric shock. GFI outlets have three holes in a triangle pattern; there are two vertical slots and a round hole between them The shorter slot is called the “hot,” the longer slot is the “neutral” and the round hole is called the “ground.”

Typically, all electricity will flow from the “hot” slot through an appliance plugged into the outlet, and back into the “neutral” slot. The GFI outlet monitors the current flowing to and from the appliance. If the outlet senses an imbalance in the current flowing from the hot to the neutral slots, it will disconnect electricity flowing to the outlet. Most GFI outlets are very sensitive, and are capable of detecting a current imbalance of just a few milliamps.

Such an imbalance generally means there is a current leak somewhere-the worst case scenario being that the missing current is flowing into a human, instead of back to the neutral outlet. GFI outlets shut off current quickly, in less than one-tenth of a second, so that extra current will not flow where it’s not supposed to.

It can be difficult to know if you have GFI outlets in your home just by looking at them. They are recommended in areas of a building where there is water, because moisture increases the risk of electric shock (picture someone dropping a hairdryer into the sink). A few decades ago, they generally were only installed around pools and boathouses, but now are commonly found (and required by building code in Alaska) in places like bathrooms, garages, kitchens, crawl spaces, unfinished basements and outdoor outlets.

Heat tape should be plugged into a GFI outlet because heat tape is typically protecting water pipes and therefore has the potential to be exposed to moisture.

Some GFI receptacles have test/reset buttons on them. You can check if the GFI protection on these outlets is working by pushing the test button — which should shut off the current to any device plugged into the outlet. Pushing the test button will also cause the reset button to pop out. You can turn the outlet back “on” by pressing the reset button. GFI outlets can fail as power surges from the utility can damage their internal circuits, so testing them occasionally is a good idea.

Other outlets have GFI protection at an “upstream” outlet or at the distribution panel and may have no test/reset button. In this case, to test a specific outlet, you will need to push the test/reset buttons on the upstream outlet or at the distribution panel.

Installing GFI outlets

It’s just as easy as installing a regular outlet, though you need to pay attention to ensure the proper terminals are connected to the source. It takes a little extra consideration to wire it up if you are using it to protect outlets downstream.

GFI outlets cost more to install than regular outlets. While a regular outlet can cost as little as a few dollars, GFI outlets can cost more than $20. This adds up when considering every outlet in a home and explains why electricians may install GFI protection at the panel rather than at each individual outlet.

A similar type of outlet is an arc fault circuit interrupters (AFCI). These are required in the living room, bedrooms, hallways, at lighting circuits, and use a special circuit breaker at the distribution panel. While GFIs are designed to protect you from shock, AFCIs are designed to prevent fires when an electrical arc is caused by, for example, driving a nail into the wall and hitting a wire. GFI receptacles cannot be used on an AFCI circuit.

Report: Fairbanks should invest in energy efficiency instead of new sources

From The Fairbanks Daily News-Miner, Thursday, January 6, 2011:

We try to get the most mileage out of our cars, clothing, food and other commodities before buying more. But we don’t make the most of the electricity we have, a new report states of Fairbanks.

The report states it can be cheaper to invest in energy efficiency than in new sources of energy. It shows Fairbanks can cut its energy demand almost in half by investing $100 million in efficiency. That doesn’t mean turning down the heat but rather insulating and installing more efficient appliances and patching up other electricity-sucking devices.

A panel of state and local officials and energy experts convened Wednesday morning at the Morris Thompson Cultural and Visitors Center to discuss the report and the potential of energy conservation in Fairbanks. They said energy efficiency would save money, improve the local business climate and create jobs.

“Energy efficiency and conservation will always be our best economic value and most secure investment. It comes with a high, tax-free rate of return,” said Todd Hoener of Golden Valley Electric Association.

The report, titled Fairbanks First Fuel, was commissioned by the non profit Alaska Conservation Analysis. It explores how Fairbanks residents, businesses and industries use electricity and how they could reap savings by investing in efficiency. It recommends measures for different sectors and gives costs and paybacks of various technologies.

Our Alaska: Living off the grid

From Alaska Dispatch, Sunday, January 2, 2011:

When general contractor David Doolen and his wife Dale bought land far up Rabbit Creek Valley more than 25 years ago, they weren’t planning on disconnecting from the municipal power grid. But back then the muni would have charged the Doolens $60,000 to run up a line to connect the house to city power, so they decided to keep the lights on using solar power and a generator. Today they’ve got two solar panels in addition to the diesel generator, which is connected to a 300-gallon tank that needs filling about twice a year. One side benefit of this unique setup: When the rest of Anchorage suffers through a blackout, the Doolens’ lights stay on. “We always feel pretty smug when that happens,” David said.

Watch the video: Our Alaska: Living off the grid

Nenana may be getting experimental in-river power turbine

From The Fairbanks Daily News-Miner, Monday, December 27, 2010:

Federal regulators are reviewing plans for a submerged, in-river power turbine. It’s a pilot project energy researchers and the developer think could help communities across rural Alaska, where electric costs run exponentially higher than in urban hubs.

Two similar projects have been tested in Ruby and Eagle. This one, lined up for use near Nenana, would be bigger — between 50 and 300 kilowatts, via small turbines and an underwater transmission cable in the Tanana River. It would operate a little less than half the year.

Monty Worthington, a project development director for the Anchorage-based ORPC Alaska, said he hopes to have the system up and running in 2012.

Anchorage elementary getting wind turbine

From The Associated Press, Tuesday, December 21, 2010:

Begich Middle School in Anchorage has won school board approval to install a wind turbine.

The Anchorage Daily News reports it’s part of a federal program to teach renewable energy. The turbine will generate enough electricity to run up to eight computers.

Alaska is one of 11 states in the Energy Department’s Wind for Schools program.

Sherrod Elementary in Palmer also has a turbine. Schools in Juneau are working with the Coast Guard station’s wind turbine.

Continue reading: Anchorage elementary getting wind turbine

Is a Small Wind Energy System Right for You?

From the U.S. Dept. of Energy, Wednesday, November 17, 2010:

When I think of wind technology, an image comes to mind of a towering fleet of turbines. Although I’ve never seen a wind farm up close, I’ve heard from several people that it’s an awe-inspiring sight. I may not have the chance to see a large-scale wind farm anytime soon, but I have had the opportunity to examine a small wind energy system—an alternative source of energy that can fully or partially provide power for the home.

During a recent visit to the U.S Botanic Gardens (USBG) in Washington, D.C., I noticed a vertical wind turbine on display. This single turbine, relatively small in stature, provides up to 2,000 kilowatt hours per year for the USBG. The Garden’s horizontal wind turbine provides an additional 2,500 kW hours per year. Although D.C. is not an ideal windy city, the USBG estimates that these turbines generate enough electricity to light its annual holiday show and power its electric utility vehicle.
In the same way, a small wind energy system can provide a significant amount of clean, renewable energy for your home. Wind turbines work by converting the kinetic energy of wind into electricity. The blades of the wind turbine are aero-dynamically designed to capture the maximum energy from the wind. The wind turns the blades, which spin a shaft connected to a generator that in turn produces electricity. Check out our Energy 101 video series to learn more about wind energy basics.

Continue reading: Is a Small Wind Energy System Right for You?

Nissan Will Sell 500,000 Electric Cars a Year by 2013, Says Chief

From The New York Times,  Tuesday, November 16, 2010:

On the eve of the market debut of the Nissan Leaf electric car, Carlos Ghosn, chief executive of the Renault-Nissan alliance, said the only constraint on sales for the next three years will be how many battery packs the factories could churn out.

Deliveries of the Leaf are scheduled to start next month. Mr. Ghosn, speaking to reporters in Washington on Monday afternoon, did not say just how many he expected to sell in the first three years. He said, however, that the Leaf would hit 500,000 units a year in three years. Mass production, he explained, would lower costs enough to make the car a sales success without subsidies sooner than once expected. He said he once thought that number was a million cars a year, but now believed it was from 500,000 to 1 million.

“We’re going to have to put some efforts into selling the car, but the kind of spontaneous demand is going to be driving the sales for the next three years,” Mr. Ghosn said. “There is such a curiosity about the car and attention to the car.”

He predicted that 10 percent of the world car market would be electric vehicles by 2020. “There is no doubt in the minds of anyone in the industry that this is going to be a big factor in the industry,” he said.

Continue reading: Nissan Will Sell 500,000 Electric Cars a Year by 2013, Says Chief

Offshore Wind Power Line Wins Backing

From The New York Times, Tuesday, October 12, 2010:

Google and a New York financial firm have each agreed to invest heavily in a proposed $5 billion transmission backbone for future offshore wind farms along the Atlantic Seaboard that could ultimately transform the region’s electrical map.

The 350-mile underwater spine, which could remove some critical obstacles to wind power development, has stirred excitement among investors, government officials and environmentalists who have been briefed on it.

Google and Good Energies, an investment firm specializing in renewable energy, have each agreed to take 37.5 percent of the equity portion of the project. They are likely to bring in additional investors, which would reduce their stakes.

If they hold on to their stakes, that would come to an initial investment of about $200 million apiece in the first phase of construction alone, said Robert L. Mitchell, the chief executive of Trans-Elect, the Maryland-based transmission-line company that proposed the venture.

Marubeni, a Japanese trading company, has taken a 15 percent stake. Trans-Elect said it hoped to begin construction in 2013.

Continue reading: Offshore Wind Power Line Wins Backing

Developer hopes to capitalize on wind power near Delta Junction

From The Fairbanks Daily News-Miner, Sunday, September 26, 2010:

A Fairbanks developer said Tuesday he hopes he can build a 25-megawatt wind farm near Delta Junction despite limited avenues for public aid.

Mike Craft said his firm, Alaska Environmental Power, is working with Golden Valley Electric Association to study how to best feed wind power into Interior Alaska’s transmission grid.

The work parallels planning by Golden Valley for a separate wind farm near Healy.

Craft told a chamber of commerce audience Tuesday he hopes the integration studies will lead to power-sale agreements between his firm and the utility. He said Golden Valley previously agreed to a smaller, pilot sale agreement following construction of two smaller turbines at the Delta site.

“(It) made it possible for us to come on line with these two turbines. That helped us a lot,” Craft said. He said the turbines, the largest built with state aid, have produced 134,000 kilowatt-hours of electricity.

Craft, a builder and residential developer, started looking to enter the wind power business roughly three years ago. He approached public officials last winter for help with his project and received lukewarm responses but said Tuesday he chose to continue and hopes to install 16 GE turbines near Delta.