Friday, November 5, 2010

A Guide to Surge Protection


Today’s electrical appliances, stereo equipment and computer systems are much more important to our daily lives than we’d like to imagine. Our computers are our link to the world around us. They have become a center-point in the daily lives of many families. Think about it, what would you do if your computer burned up? Could you afford to replace it on a moment’s notice, and what about all the valuable data stored on it? Could you easily replace the Plasma screen television you bought for the holidays? You may want to consider protecting your valuable electronics with a proper surge protector.
What is a surge protector? A surge protector is your first line of defense against voltage surges or spikes in your home or office’s electrical system. Typically, a “surge” is when the voltage in your home increases slightly and lasts for about three nanoseconds. A “spike” is a voltage increase that lasts for one to two nanoseconds. Either one can have a devastating effect on your delicate electronics if they are unprotected.
Surge protectors come in many sizes, shapes and variations. Sometimes called a “power strip”, most homeowners know them for being able to extend the number of outlets available on a given wall outlet, like a more convenient extension cord. Unbeknownst to most homeowners, that so-called “power strip” can be a money saver if it’s ever called upon to do its job.

Friday, June 18, 2010

Extension Cords

Extension Cords
Normal wear on cords can loosen or expose
wires. Cords that are not 3-wire type, not
designed for hard-usage, or that have been modified,
increase your risk of contacting electrical current.
• Use only equipment that is approved to meet
OSHA standards.
• Do not modify cords or use them incorrectly.
• Use factory-assembled cord sets and only extension
cords that are 3-wire type.
• Use only cords, connection devices, and fittings
that are equipped with strain relief.
• Remove cords from receptacles by pulling on
the plugs, not the cords.

Generators......

Generators
One of the common tools utilized following the
loss of power are portable generators. Most
generators are gasoline powered and use internal
combustion engines to produce electricity.
Carbon monoxide is a colorless and odorless gas
produced during the operation of gasoline powered
generators. When inhaled, the gas reduces
your ability to utilize oxygen. Symptoms of
carbon monoxide poisoning include headache,
nausea and tiredness that can lead to unconsciousness
and ultimately prove fatal.
• DO NOT bring a generator indoors. Be sure it is
located outdoors in a location where the
exhaust gases cannot enter a home or building.
Good ventilation is the key.
• Be sure that the main circuit breaker is OFF and
locked out prior to starting any generator. This
will prevent inadvertent energization of power
lines from back feed electrical energy from
generators and help protect utility line workers
from possible electrocution.
• Turn off generators and let them cool prior to
refueling.

Sunday, April 4, 2010

Service Entrance Equipment

"The System Ground relates to the Service Entrance Equipment and the interrelated and bonded components; that is, the system and circuit conductors are grounded to limit voltages due to lightning ,line surges, or unintentional contact with higher voltage and to stabilize the voltage to ground during normal operation per NEC Sections 250.4(A)(1) and(2)"
nccer Training Guide


Saturday, April 3, 2010

Grounding Electric Services Part 4

A wire that is used to connect electrodes is referred to as a grounding electrode or electrodes is referred to as a grounding electrocde conductor (GEC). Note there is a difference in the two meanings: One is grounded, while the other provides a means for grounding.


Grounding Electric Services..part 3

The word Ground refers to ground potential or earth ground. If a conductor is connected to the earth or some conducting body that serves in place of the earth, such as a driven ground rod(Electrode), the conductor is said to be grounded. The neutral conductor in a three-or-four wire service,for example, is intentionally grounded, and therefore becomes a grounded conductor.

Grounding Electrical Services part 2

Proper Grounding ensures that the electrical charges that cause these higher voltages are channeled to the earth or ground and that an effective ground fault path is provided throughout the system so that the overcurrent devices will open before people are endangered or equipment is damaged.

Grounding Electric Services..

The Grounding system is a major part of the electrical system. It’s purpose is to protect People and Equipment against the various Electrical faults that can occur. It is sometimes possible for higher than normal voltages to appear at certain points in an electrical system or in the electrical equipment connected to the system.

Wednesday, March 31, 2010

Am I In Danger?

Due to the dynamic, rugged nature of construction work, normal use of electrical equipment at your site causes wear and tear that results in insulation breaks, short-circuits, and exposed wires [for additional information, see Flexible Cords and Power Tools]. If there is no ground-fault protection, these can cause a ground-faultthat sends current through the worker's body, resulting in electrical burns, explosions, fire, or death.

How Do I Avoid Hazards?
  • Use ground-fault circuit interrupters (GFCIs) on all 120-volt, single-phase, 15- and 20-ampere receptacles, or have an assured equipment grounding conductor program (AEGCP).
  • Follow manufacturers' recommended testing procedure to insure GFCI is working correctly.
  • Use double-insulated tools and equipment, distinctively marked.
  • Use tools and equipment according to the instructions included in their listing, labeling or certification.
  • Visually inspect all electrical equipment before use. Remove from service any equipment with frayed cords, missing ground prongs, cracked tool casings, etc. Apply a warning tag to any defective tool and do not use it until the problem has been corrected.

Saturday, March 27, 2010

Cords & Appliances

Cords & Appliances

Cords & Appliances


Cords, Equipment, and Tool Grounding

  • Make sure all equipment and extension cords bear the mark of an independent testing laboratory such as UL, CSA, ETL or MET Labs.

  • Protect flexible cords and cables from physical damage. Check cords for cut, broken, or cracked insulation.

  • Keep slack in flexible cords to prevent tension on electrical terminals.

  • Make sure the insulating qualities of a splice are equal to or greater than the original cord.

  • Extension cords are for temporary use. Install permanent wiring when use is no longer temporary.

  • Verify that all three-wire tools and equipment are grounded.

  • Water, electrical equipment, and power cords do not mix! Use GFCI protection in wet or damp environments.

  • Ground exposed parts of fixed equipment that could be energized.

  • Use non-conductive tools whenever possible.

  • Always double check the operation of your voltage testers by testing a live circuit.

Thursday, March 25, 2010

ELECTRICAL SOURCES IN HAZARDOUS LOCATIONS

ELECTRICAL SOURCES IN HAZARDOUS LOCATIONS

An explosion or fire can cause all sorts of havoc in any company's operations. Rebuilding, after a fire, can take a company years. One of the major causes of explosions and fire in industry is from electrical sources. Potential losses from these fires can be reduced by having proper electrical installations and equipment.

Hazardous locations require specially designed electrical equipment to protect people and property against increased fire potential. Certain electrical components and instruments are engineered specifically for locations designated as hazardous due to the possible presence of ignitable quantities of flammable liquids, gases, vapors, combustible dusts, or ignitable fibers.

Hazardous locations are classified as Class I, Class II, or Class III. The class is dependent on the physical properties of the combustible materials which may be expected to be present.

  • Class I locations are those in which flammable vapors or gases may be present.
  • Class II locations are those in which combustible dusts may be found.
  • Class III locations are those in which there are ignitable fibers and filings.

Each of these three classes are divided into two hazard categories, Division 1 and Division 2. The divisions identify the degree of potential for an ignitable atmosphere to exist. Class and Division explanations are detailed in Articles 500 - 503 of the National Electric Code (NEC), and in OSHA 29CFR 1910.39.

Before selecting electrical equipment and the associated wiring for any hazardous location, the exact nature and concentrations of the flammable materials must be determined. An electrical fitting or device which is safe for installation in an atmosphere of combustible dust may not be safe for operation in an atmosphere containing flammable vapors or gases. These electrical fittings are specifically designed for each hazard.

Class I electrical wiring applications are commonly referred to as "Explosion Proof." Properly installed and maintained class I equipment will not ignite the dangerous atmosphere surrounding it, and is approved for use in specific hazardous areas. Explosion proof fittings are designed to contain any arcing, intense heat, and explosions. These fixtures are distinctive in appearance. Class II locations may require "Dust-ignition proof" fixtures. These fixtures are designed in such a manner that their construction prohibits ignitable amounts of dust from entering the devices.

Hazardous areas that must have approved electrical installations include, but are not limited to: locations where volatile flammable liquids are transferred from one container to another; interiors of spray booths; in the vicinity of spray painting operations where volatile flammable solvents are used; locations where dangerous concentrations of suspended dust are likely, such as in grain elevators; and gasoline fueling stations. Remember to think electrical safety when proposing any electrical systems that will be located in a hazardous location.