Halogen light bulbs are much more versatile and efficient when compared to their incandescent ancestors. Halogen lamps differ from incandescent lamps in how they operate, the materials they are made of, the brightness, and even in aspects as trivial as shape.

Let’s start at the surface. The glass surface of a halogen lamp is not made of typical, ordinary glass, but is made of quartz.  Quartz resists higher temperatures and can therefore be situated closer to the filament. This feature allows halogen bulbs to be smaller than incandescent bulbs. They are brighter and thus hotter than your ordinary light bulbs. These electric lamps last longer than typical incandescent bulbs because the tungsten in the filament undergoes recycling processes and this prevents rapid loss of the tungsten element. This feature also retards blackening of the quartz surface.

These halide containing lamps come in variety of shapes which allow them to be used in a wide array of purposes from general lighting to decorative accent purposes. Nevertheless, replacing these lamps and changing these bulbs is not specifically difficult, necessary precautions and measures must be observed in handling these objects.

First and foremost, make sure the device is turned off or unplugged. For general safety, never touch the bulb with your naked skin because the oil on your skin is a hazardous impurity on the surface of the bulb. When the bulb gets hot, the oil attacks the surface and creates a weak spot. This leads to shortening of the life span of the light bulb. In severe cases, the weak spot may lead to bulb failure and explosion. Thus, you must wear gloves while holding the bulb. Ensure the quartz surface does not get in contact with the skin. Clean cloth or paper towel may be used.

If the lamp has just been used and switched off, wait for a while before attempting to remove the bulb. It is advised to wait for at least fifteen minutes to allow it to cool down to room temperature. This will prevent serious burn injury. Take note that halogen light bulbs are hotter than ordinary bulbs. Once the bulb reaches its termination stage and burns out completely, then it is time to replace it. However, give ample time for it to cool and again use gloves and try as much as possible to not touch the quartz surface.

Remove the old busted bulb by unscrewing it from the socket just as you would remove any other light bulbs. If the old bulb is totally busted, you may hold it with your bare hands as long as you have allowed it to cool. Screw the new bulb in place with your gloved hands. Again, do not touch the bulb surface with your bare hands at any time. Turn on the power and see if the bulb lights appropriately.

The use of halogen lamps must be accompanied with safety precautions. These lamps are no typical lamps at home. They are much hotter than typical light bulbs and may cause serious burns through direct contact. Flammable materials should be kept away from direct contact with the lamp surface while turned on. Moreover, these burning lamps emit huge amounts of energy and some ultraviolet radiation. Thus, it is believed certain duration of exposure to these lights may cause symptoms like that of sunburn. Nonetheless, lots of halogen lamps have UV filtered quartz bulb surface.

Note that if at any case, you came to touch the surface of the halogen bulb, wipe the surface thoroughly with alcohol and allow it to dry completely before turning it on.

From the point of view of the power system, the most important issues concern how and where and when the vehicles recharge. As the report points out, consumer recharging choices will be significantly affected by retail rate designs. A flat rate means that consumers will not be dissuaded from adding to overall electric load at peak times, when the transmission system is congested and high-cost generation units must run to keep the system operating. Time-of-use rates or market-driven prices will encourage consumers to shift charging to off-peak periods.

The flat rate scenario will require additional investment in electric generation, transmission and distribution systems, while the more reasonable pricing systems may allow the power system to accomodate significant numbers of PHEV with little or no additional investment in supply-side capacity.

It should go without saying that smart grid systems (devices and commercial practices) could play a critical role in getting the most consumer value out of a PHEV.

The NYISO report draws from three much more detailed technology analyses, one by Oak Ridge National Laboratory, another by the Electric Power Research Institute  and the Natural Resources Defense Council, and the third by Pacific Northwest National Laboratory, and several other studies. Despite the tentative nature of the NYISO report, it provides a concise, readable introduction to the issues addressed at more length in the technical studies.  In addition, the NYISO report includes an extensive bibliography.

Not a bad place to start if you are interested in understanding these issues.

RELATED: EPRI and PJM conducted a “PHEV Summit” in January of this year, exploring these same issues.

Source: http://knowledgeproblem.com

Electricians have various job titles. Construction electricians handle the actual wiring of buildings. Service or maintenance electricians are primarily responsible for troubleshooting wiring problems and making necessary repairs. One can also choose to work in the specialty areas of research electricians, marine electricians, or hospital electricians.

Electricians work with transformers, motors, electronic controllers, and generators. They install electrical equipment in accordance with the codes of public safety. For the installation process, electricians generally consult blueprints. They may also have to work in tandem with line installers, maintenance workers, engineers, and engineering technicians.

Candidates wishing to take up the profession of electricians should have appropriate training in the field. A number of apprenticeship programs are available, and for enrollment to these courses one needs a GED or a high school diploma. Organizations like the International Brotherhood of Electrical Workers, Associated Builders and Contractors, National Electrical Contractors Association, and Independent Electrical Contractors Association sponsor apprenticeship programs for electricians. These courses generally last for about four years and include both classroom instruction and on-the-job training. Electricians are taught mathematics, electrical theories and code requirements, blueprint reading, as well as safety procedures.

Prior to joining the profession, an electrician must obtain licensure. This is mandatory in all states, and the requirements for licensing vary from one state to the other. Generally, one is required to pass an examination on electrical theories and codes in order to get the license. Those wishing to become master electricians also need to have licensure for which a bachelor’s degree and at least seven years of work experience as an electrician.

Continuing education is an important criterion for electricians. They need to attend safety programs, management training courses, and manufacturer-specific trainings at regular intervals.

Getting the Job
Interested candidates can get in touch with organizations like the Associated Builders and Contractors, Independent Electrical Contractors, Inc., International Brotherhood of Electrical Workers, Home Builders Institute, and National Electrical Contractors Association. These associations generally offer apprenticeship programs as well as information about job prospects. There are various union-management committees that list job openings. Often, organizations advertise their requirements on job portals or the classified sections of newspapers. Besides, one can also approach local firms or electrical contractors for jobs.

Advancement Possibilities and Employment Outlook
With experience, electricians can advance to administrative and supervisor positions. Most electricians go on to become electrical inspectors. The advancements depend on their respective job profiles. For instance, construction electricians can take up the roles of superintendents and project managers. One can also set up a contracting business or transfer to related jobs like that of maintenance electricians and equipment installers and repairers. Advancement possibilities are the best for those having good communication skills in English and Spanish.

The job market for electricians is expected to grow by 7 percent in the next ten years. Employment opportunities are largely dependent on the location and specialty. Those working in power plants in fast-growing regions of the country are expected to have the best opportunities. Electricians in electrical contracting organizations will also have very good prospects in the near future.

Working Conditions
In consideration of the nature of their work, electricians should be prepared to work in all kinds of weather conditions. Most of their work is carried out at construction sites, which may be outdoors or indoors depending on the project. Electricians normally have 40-hour work week with the possibility of overtime. Those employed in maintenance services may frequently have to work at odd hours in the evenings and nights. Also, due to the nature of their work, electricians are prone to injuries from cuts, falls, and electric shocks.

Where to Go for More Information
National Joint Apprenticeship Training Committee
301 Prince George’s Blvd.
Upper Marlboro, MD 20774
http://www.njatc.org

National Electrical Contractors Association
3 Metro Center, Suite 1100
Bethesda, MD 20814

http://www.necanet.org

International Brotherhood of Electrical Workers
1125 15th St. NW.
Washington, DC 20005

Earnings and Benefits
The median hourly wage of electricians, as per the data of May 2006, was $20.97. The wages can range anywhere between $12.76 and $34.95 on an hourly basis. Entry-level electricians earn about 40% to 50% of the earnings of skilled electricians. However, wages are increased at regular intervals throughout the training periods. According to research, the annual mean earnings of electricians employed in motor vehicle parts manufacturing industries are about $65,680, while those working in motion picture and video industries earn around $82,450.

Electricians generally enjoy regular benefits like paid leaves and vacations, generous retirement plans, and insurance.

Source : careers.stateuniversity.com

Based on the underlying danger that exists in these structures, it’s fitting that they’re deemed Class I Division 1 zones. To mitigate risks, most commercial garages currently under construction are opting for above-slab lifts, while many older buildings have discontinued their pits. Despite this step forward, amid all of this combustible material, there is still extensive use of electricity in lighting, portable power tools, arc welding, and battery-charging equipment — together with large motors. All of this means the electrical installation must be impeccable. As an electrician or electrical contractor, the best way to start is by complying with applicable Code mandates in the design stage. Let’s take a look at what’s involved in wiring commercial garages.

Initial Assessment
Examining Art. 511, we see the commercial garage has vertical and horizontal boundaries, and the delineated areas are classified according to the degree of hazard encountered. We also see that the authority having jurisdiction (AHJ) can derate some of these classifications if:

The building’s use will be restricted to the extent that fuel systems will not be opened. (This would preclude major engine work or fuel system repairs, including replacement of fuel filters and fuel pumps.)

Positive air ventilation will be in place at all times (even nights and weekends) as long as vehicles are present.

If you’re in the design stage of a commercial garage, it’s probably better not to take advantage of either of these options. A better approach is to design the whole building so that a given area is considered Class I Division 2, but wiring is kept out of that zone. Moreover, in the life of the building, the installation and maintenance of an air-venting system means a large amount of energy, parts, and upkeep — just to downgrade a classification. How do you avoid these pitfalls? By proper planning on the front end.

Design Considerations
Design work for a commercial garage should address all facets of the proposed construction. The first step is to size out the service. Table 220.12 gives the general lighting load for various occupancies. Commercial garages require ½VA per square foot. This may not sound like much, but remember that unlike dwelling units, the receptacle load is not included in this figure. It has to be added to it, along with all other loads. The ½ ampere-per-square-foot is for lighting only. Thus, the designer has to enumerate all receptacles, motors, and other equipment to calculate the total load (see Table).

If any of the motors will be 5 horsepower or higher — or if there will be heavy arc welding work performed in the building — now is the time to install a 3-phase service. In the early stage of design work, a meeting with the electric utility should take place to agree on type of service, rate structure, and where the service drop or lateral will hit the building. Will a masthead be necessary to achieve minimum ground clearance? If so, you can size out and design the service including metering and ground electrode conductor entry into the concrete.

For a large building, over 100 feet in greatest dimension, you may want one or more feeders and subpanels to minimize voltage drop. All structural metal, water pipe, metal ductwork, gas, air lines, and the like should be solidly bonded back to the service neutral at the main bonding jumper. At that point, the grounded neutral and the equipment-grounding conductor separate — never to rejoin.

Branch circuits higher than 18 inches above the slab (and 18 inches below the ceiling if compressed natural gas will be allowed) should be placed in EMT and MC (or flexible conduit as needed). Under this arrangement, continuous ventilation is never required, and a full range of mechanical work is allowed, including fuel tank changes and major engine overhauls.

Although Art. 511 is only a few pages long, it should be carefully scrutinized. The key is to make sure all wiring is located well outside any horizontal or vertical boundaries.

Special Concerns
Classified areas within a commercial garage are delineated in 511.3 (B). In the event that flammable fuels will be dispensed into vehicle fuel tanks inside or outside the building, such areas must also conform with Art. 514, Motor Fuel Dispensing Facilities.

If there will be a spray room for automotive painting, it must comply with Art. 516, Spray Application, Dipping and Coating Processes. Here again, rather than design to Class I specifications (rigid or intermediate conduit, Type MI cable, etc.), it’s possible to locate all lighting behind indestructible translucent or transparent panels. All wiring should be effectively partitioned from the interior of the spray room, as should any motors and associated equipment that drive ventilation fans. Spray fumes should be vented to a dedicated area outdoors high above grade, and separated from any source of ignition and from any air intake.

If effectively partitioned from the garage service areas, offices, parts rooms, and employee lunchrooms are excluded from the classified zone area. However, the entries to all unclassified areas must have doorsills more than 18 inches above the garage floor. This feature should be addressed early in the design phase so that it’s reflected in the foundation plan.

Battery-charging equipment and batteries being charged must be in one of these partitioned rooms. Such an area should be fairly large with a high ceiling to allow hydrogen to dissipate. It should be vented, but not back into the service area. A welding room, with noncombustible wall material, should be partitioned off from the main service area and be provided with receptacles sized to match the arc welding equipment that will be used. These will be hardwired back to the panel with no additional disconnect since the welders have unit switches.

So far, we’ve considered fire and explosion hazards, but there is another serious danger lurking in the commercial garage work environment: electric shock.

Avoiding Underlying Danger
Electric shock hazards can be offset by Code compliance. As per the Code, all 125V, single-phase, 15A and 20A receptacles in commercial garages where electrical diagnostic equipment, electrical hand tools, or portable lighting equipment are used must have GFCI protection. This can be achieved by installing either circuit breaker or receptacle-type devices. The least expensive but perfectly compliant and effective way to meet this requirement is by using the feed-through capability of a GFCI receptacle to protect downstream receptacles, which should be identified by affixing the stickers provided. Such GFCI protection is needed for outdoor receptacles as well.

These outdoor devices need in-use (bubble) covers in case vehicles will be left unattended with block heaters plugged in. Article 210, which covers GFCI protection for branch circuits, also requires this technology for all receptacles in non-dwelling bathrooms, kitchens, and rooftops, if equipped for servicing heating and air conditioning.

Fire and explosion hazard resulting from electrical wiring juxtaposed with flammable gas and liquid fuels found in commercial garages is better mitigated by locating wiring outside the classified areas, rather than wiring to Class I standards inside those areas or by encumbering the building with a ventilation system that would have to be maintained in perpetuity or by limiting the scope of work permitted. Careful planning and design work can avert human injury and property loss in the future, making for an efficient and profitable operating environment.

Low-Voltage Accommodations
Increasingly, low-voltage wiring is becoming a part of the electrician’s scope of work on commercial garage jobs. For example, telephone and satellite (or cable) Internet, properly grounded, should enter the building at an appropriate place based on outside parameters and be distributed to points of use.

The office, customer service counter, and parts department will need computers connected to the Internet — possibly in a networked configuration. These same areas need telephones every 30 feet within the service area of the garage. Install Cat. 5e or Cat. 6 UTP cable in EMT to all points of use.

Although the Code does not mandate cable fill limitations, four or five cables are the most you can fit in ¾-inch EMT, depending on the geometry of the run. Telephone and Ethernet cables can occupy the same pipe, but not power conductors. You can run 1-inch main lines and ¾-inch drops to the individual points of use. Wall boxes with faceplates incorporating an RJ45 modular Ethernet connector for Internet access, and an RJ25 for telephone will provide excellent service. You can also run coax cable to the office and employee lunchroom if TV is desired. Because the service area can be noisy, there should be public announce capability (audio cabling cannot occupy the same raceway with low-voltage conductors) and an AC-powered telephone ringer.

Lighting The Way
Lighting a commercial garage can also create challenges for the designer. For ceiling heights below 16 feet, low-bay lighting fixtures are the best choice. High-bay fixtures work well where the ceiling height is 20 feet or greater. Ordinary cool white T8 fluorescent fixtures are good over workbenches and other high-use areas.

All lighting should be carefully zoned so that the entire building does not have to be lighted at once. Three- and four-way switching should be provided for walk-through lighting, and a small number of T8 fixtures the length of the garage should be unswitched so that the area is never in total darkness. Battery-powered emergency light units, which also drive exit lights, should be tied into the unswitched lighting circuits. Lighting in a commercial garage is considered a continuous load, rated at 125%, since it is expected to operate over 3 hours.

Receptacles should be provided for all bench areas. They can consist of two duplex straps per 4×4 surface-mount box with raised faceplate. The NEC does not require any particular spacing, so it’s up to the designer. They should be abundant to minimize the use of extension cords, and, as previously mentioned, all must be GFCI protected. If these are piped in EMT and mounted along the wall 6 inches above the bench, they will be easy to use and well out of the classified area.

Article source : http://www.ecmweb.com

The blackout on August 14, 2003 was the biggest in U.S. history. And just like every major blackout, it raised a lot of questions about how our power distribution system works.

At a high level, the power grid is a very simple thing. It consists of a set of large power plants (hydropower plants, nuclear power plants, etc.) all connected together by wires. One grid can be as big as half of the United States. (See How Power Distribution Grids Work to learn about the different pieces of the grid.)

Photo courtesy U.S. Department of Energy A breakdown of the major power plants in the United States, by type

A grid works very well as a power distribution system because it allows a lot of sharing. If a power company needs to take a power plant or a transmission tower off line for maintenance, the other parts of the grid can pick up the slack.

The thing that is so amazing about the power grid is that it cannot store any power anywhere in the system. At any moment, you have millions of customers consuming megawatts of power. At that same moment you have dozens of power plants producing exactly the right amount of power to satisfy all of that demand. And you have all the transmission and distribution lines sending the power from the power plants to the consumers.

Photo courtesy U.S. Department of Energy A map of U.S. electric control area operators (CAO). Computerized systems at each CAO monitor the power grid activity and balance power generation (supply) with power consumption (demand).

This system works great, and it can be highly reliable for years at a time. However, there can be times, particularly when there is high demand, that the interconnected nature of the grid makes the entire system vulnerable to collapse. Here’s how that happens:

Let’s say that the grid is running pretty close to its maximum capacity. Something causes a power plant to suddenly trip off line. The “something” might be anything from a serious lightning strike to a bearing failure and subsequent fire in a generator. When that plant disconnects from the grid, the other plants connected to it have to spin up to meet the demand. If they are all near their maximum capacity, then they cannot handle the extra load. To prevent themselves from overloading and failing, they will disconnect from the grid as well. That only makes the problem worse, and dozens of plants eventually disconnect. That leaves millions of people without power.

The same thing can happen if a big transmission line fails. In 1996 there was a major blackout in the western U.S. and Canada because the wires of a major transmission line sagged into some trees and shorted out. When that transmission line failed, all of its load shifted to neighboring transmission lines. They then overloaded and failed, and the overload cascaded through the grid.

In nearly every major blackout, the situation is the same. One piece of the system fails, then the pieces near it cannot handle the increased load caused by the failure, so they fail. The multiple failures make the problem worse and worse and a large area ends up in the dark.

One solution to the problem would be to build significant amounts of excess capacity — extra power plants, extra transmission lines, etc. By having extra capacity, it would be able to pick up the load at the moment that something else failed. That approach would work, but it would increase our power bills. At this moment we have made the choice as a society to save the money and live with the risk of blackouts. Once we get tired of blackouts and the disruption they cause, we will make a different choice.

 

Big Blackouts in U.S. History The Great Northeast Blackout of 1965: After a relay failure, more than 80,000 square miles of the northeastern United States and parts of Canada lost power, turning the lights out on 30 million people.  The New York Blackout of 1977: One hot night in July, multiple lightning strikes knocked out power to the entire city of New York, leaving 8 million people without light or air conditioning. The blackout triggered mass looting and arson across much of the city.  The Northwestern Blackout of 1996: Transmission lines sagged into some trees, causing an electrical short that knocked out power to more than 4 million people in Oregon, California and other western states.  The Blackout of 2003:Cities across the midwestern United States, northeastern United States and southern Canada lost power, apparently due to a problem with a series of transmission lines known as “The Lake Eerie Loop.” Roughly 50 million people lost power.

 

Article Source :  http://science.howstuffworks.com/blackout.htm

I knew that by bringing your electric power of out the house and into the outside area of your home will literally extend the amount of space that you can use for lights, your computer, your kitchen appliances and any other thing that you normally would use inside.  Extending electrical power to the outside of your home and into lawn areas also allows you to plug in electric lawn equipment without the use of an extension cord that runs through your window or your door! (A plus to outside electric power is that you can keep more bugs out of your house!) 

 Besides realizing that I can keep some bugs out of my home, it also dawned on me that life can be much easier having electric power outside even with all its associated switches, outlets, plugs, controls, devices, cables, conduits and the knowledge needed in order to obtain all this electrical freedom.  I knew I wanted this freedom, but I then learned that I needed an education on how to get what I wanted.

The basics of wiring are the same for both indoors and outdoors but the main difference is in how this wiring is encased.  Outside wiring will be exposed to the elements with moisture being its main challenge.  For this reason, outdoor wiring must be housed in weatherproof boxes.  The outdoor boxes must also be protected by a Ground Fault Interrupter (GFI).  A GFI  monitors the current flowing through a circuit’s hot and neutral wires.  You do not need a huge surge of electric imbalance to trip this thing.  As soon as there is a difference from one side of the electric wiring to the other, the GFI will trip and the device, appliance, light, mower, or whatever is running, will turn off.  Once the electric is balanced again, you can press the restore button on the GFI.  This will, once again, shine your lights, begin your motor or whatever you had plugged into the GFI outlet.