Argo Electrical Services

Electrical Upgrades Provide Peace of Mind

Sat, 05 Nov 2011 11:24:12 +0000

Hey There,
I just wanted to stop by and thank you for your continued support
of Argo Electrical Services. Here is Our Latest video. This might
be really interesting to individuals or families that own 2 Story
homes. Many homes built in the Atlanta area in the last 20 years
don’t have enough Electrical Service to provide for coverage of
the 2 stories and when they get ready to finish the basement.
Watch this video, We have installed many of these in the past
couple of years!

If you are interested in these upgrades or any other Electrical
issues you may Have Give me a Call Today!

George Argo
Argo Electrical Services
ArgoElectrical.com
770-596-1437

Home Automation Systems Shop online for home automation systems, lighting controls, light fittings and multi-room audio systems with fast home delivery service – onidserv.com

TROUBLESHOOTING WATT AND WATT-HOUR TRANSDUCERS.

Fri, 19 Nov 2010 01:07:45 +0000

! Watt and Watt-hour transducers are both phase and polarity sensitive. Incorrect phasing or incorrect positioning of current transformers (CTs) and/or voltage transformers (PTs or VTs) will cause the transducer to register incorrectly.

! The transducer must measure both voltage and current as delivered to the load being measured.

! The number of elements refers to the number of multipliers in the watt transducer. ” 1 element for single-phase, two-wire connections.

” 2 elements for single-phase, three-wire and for three phase, three-wire connections.” 3 elements for three-phase, four-wire connections.

! Most watt and watt-hour transducers require Instrument power. This may be a separate 115-volt AC source or it may be taken from the lines

monitored. Models vary. Check the model number that you have.

! Lightly loaded induction motors consume very little power. If one is testing an unloaded motor, expect power factors below 0.1. If you think this strange, try turning the unloaded motor shaft by hand. Easy isn’t it! The unloaded motor doesn’t require much power to turn. Remember that power in watts is the measure of the rate at which work is being done.

! Watt and watt-hour transducers with analog outputs are easy to check by measuring the analog signal.

! Watt-hour transducers with only a pulse, or closure,output require patience.

! It cannot be emphasize enough — Check and double check wiring for correctness. Phasing and polarity must be correct.! Watt and Watt-hour transducers are both phase andpolarity sensitive. Incorrect phasing or incorrectpositioning of current transformers (CTs) and/orvoltage transformers (PTs or VTs) will cause thetransducer to register incorrectly.! The transducer must measure both voltage andcurrent as delivered to the load being measured.! The number of elements refers to the number ofmultipliers in the watt transducer.” 1 element for single-phase, two-wire connections.” 2 elements for single-phase, three-wire and for threephase,three-wire connections.” 3 elements for three-phase, four-wire connections.! Most watt and watt-hour transducers requireInstrument power. This may be a separate 115-voltAC source or it may be taken from the linesmonitored. Models vary. Check the model numberthat you have.! Lightly loaded induction motors consume very littlepower. If one is testing an unloaded motor, expectpower factors below 0.1. If you think this strange,try turning the unloaded motor shaft by hand. Easyisn’t it! The unloaded motor doesn’t require muchpower to turn. Remember that power in watts is themeasure of the rate at which work is being done.! Watt and watt-hour transducers with analog outputsare easy to check by measuring the analog signal.! Watt-hour transducers with only a pulse, or closure,output require patience.! It cannot be emphasize enough — Check anddouble check wiring for correctness. Phasing and polarity must be correct.

Electrical Power and Energy Measurements

Fri, 19 Nov 2010 01:02:03 +0000

Power is defined as P = iv, where i and v are the instantaneous values of the current and voltage. For constant DC, power is simply the product of the voltage and the current. For AC power it is not quite so simple. Most watt transducers measure the instantneous power averaged over some time interval to obtain real average power.

Because watt transducers measure the rate at which work is being done they are an invaluable feedback device for discreet control of a process. Examples include cutting, grinding, heating, welding, pumping and mixing.

Watt transducers have one or more elements. Elements are also referred to as multipliers.

Remember Blondel’s Theorem:

For any (n) wire sysem, (n-1) wattmeters or elements are required to measure total power. For more information please refer to the technical paper in our Tech Library entitled “Selecting and Using Transducers for the Measurement of Electric Power, Voltage and Current”.

Almost the entire output of the electric power industry in the United States is generated and distributed as polyphase power at 60Hz. In a three phase system the three voltages are mutually out of phase by 120°. A balanced load will draw equally from the three phases: however, when one of the voltages is instantaneously zero the phase relationship shows that the other two must be at half amplitude. At no time does the instantaneous power drawn by the load reach zero. In fact the total instantaneous power drawn by the balanced load is constant. This is a big advantage for rotating machinery because it maintains a more constant torque than if a single phase motor were used.

Utility power is generally referred to as “Y” or “Wye” or a three-phase, four wire connected system. To determine the total power each of the three branches must be monitored. The total power delivered by the source load will be the simple sum of the readings of the watt meters on each branch,

OSI watt transducers for monitoring a wye-connected load have three individual multipliers (elements) contained in the transducer housing.

Polyphase watt transducers manufactured by Ohio Semitronics, Inc. are rated for voltage in two ways:

Three phase, three wire two element watt transducers are rated for line to line voltage.
Three phase, four wire three element watt transducers are rated for line to neutral voltage.

Measuring power accurately on non-linear loads can present problems. Examples of non-linear loads include UPS systems, electronic power supplies, lighting ballasts, battery chargers, variable frequency motor drives, phase angle-fired SCR controllers, zero crossing SCR controllers and pulse wave modulated controllers. While these non-linear loads can create high neutral currents, voltage distortion, heat and reduction of system power factor it is possible to measure power accurately if the correct power transducer is selected. You should consult with your OSI Technical Sales Specialist when considering the purchase of a watt tranducer which will be applied on a non-linear load.

Electrical Protection Relays

Fri, 19 Nov 2010 00:55:31 +0000

Ground Fault Relays improve the safety of workers by minimizing the conditions that may lead to Arc-Flash incidents and maximizing the uptime of critical operations by avoiding nuisance tripping. Some relays are prone to nuisance tripping, which means they disconnect power and interrupt critical processes when no fault is present. This costs an enormous amount of time and man-hours trying to locate the problem. To avoid the nuisance tripping that occurs with conventional ground fault relays, maintenance workers tend to increase trip points well above sensitive levels. This practice, although very common, is extremely dangerous as the settings are dialed up so high that the relay will trip well after the damage has occurred.

Ground Fault Relays use an advanced filtering technology that allows for early detection of developing ground faults, without the nuisance tripping common in many competing products. The Littelfuse relays can be used in ungrounded, solidly grounded, and resistance grounded systems to protect critical, high-value equipment, and to meet National Electrical Code requirements for protection of ungrounded electrical systems (NEC 250.21B), solidly grounded systems (NEC 250.95), and resistance-grounded systems (NEC 250.36). The relays also have communications for remote monitoring.

Resistance-Grounded Systems are power systems with a resistor inserted between the system neutral and ground. This limits any ground-fault current to a predetermined, acceptable level. IEEE Std. 141-1993 states that there are no Arc-Flash Hazards associated with ground fault currents if the ground fault current is limited to 5A. Simply by using a Resistance-Grounded System, safety managers can lower the risk of Arc-Flash Incidents by 95 percent. However, if the resistor in the system fails, which usually goes undetected until a problem occurs, the system becomes ungrounded. To solve this problem, the Littelfuse Resistance Grounding Systems have an optional feature that continuously monitors the integrity of the resistor to ensure that the system is operating as intended.

Motor Protection Relays prevent expensive damage to motors caused by overloads, jams, phase loss or imbalance, as well as heat from non-electric sources, heavy startups or excessive operational cycles. Littelfuse Motor Protection Relays offer dynamic thermal curves, integrated protection, metering, and data logging functions that extend motor life and maximize process efficiency. A wide range of POWR-GARD Motor Protection Relays are available to protect any size motor. In addition, Littelfuse’s products are user friendly and easy to program.

Feeder Protection Relays protect feeder circuits from overcurrent, ground faults, phase loss or other detrimental conditions. POWR-GARD’s Feeder Protection Relays provide essential data for predictive and preventive maintenance, thereby extending the life of equipment, increasing its effectiveness, and improving safety.

Article Information Local or Nation Keywords

Thu, 18 Nov 2010 22:57:54 +0000

Blah and blah

Understanding OSHA Arc Flash Regulations Here In Georgia

Tue, 16 Mar 2010 11:02:44 +0000

Understanding OSHA Arc Flash Regulations

Arc Flash Information

Tue, 16 Mar 2010 11:00:21 +0000

Q. What is an arcing fault?

A. An arcing fault is the flow of current through the air between phase conductors or phase conductors and neutral or ground. An arcing fault can release tremendous amounts of concentrated radiant energy at the point of the arcing in a small fraction of a second resulting in extremely high temperatures, a tremendous pressure blast, and shrapnel hurling at high velocity (in excess of 700 miles per hour).

Q. What causes an Electrical Arc?

A. Arcs can be initiated by a variety of causes, such as when:

Workers incorrectly think the equipment is de-energized and begin to work on it energized.
Workers drop or improperly use tools or equipment components in energized equipment.
Dust, water or other contamination accumulate and cause insulation breakdown.
Connections loosen, overheat, reach thermal runaway and fail.

Q. What is my risk to being exposed to arc flash?

A. The exposure to arc flash depends on the following:

Number of times the workers perform a task involving exposed live equipment
Complexity of the task performed, need to use force, available space, safety margins, reach, etc.
Training, skills, mental and physical agility, coordination with helper
Tools used
Condition of equipment
The available short circuit current and the condition and rating of the overcurrent protective equipment.

Q. What can happen if I am exposed to arc flash?

A. Exposure to an arc flash frequently results in a variety of serious injuries and in some cases death. Workers have been injured even though they were ten feet or more away from the arc center. Worker injuries can include damaged hearing, eyesight, and severe burns requiring years of skin grafting and rehabilitation.

Equipment can be destroyed causing extensive downtime and requiring expensive replacement and repair. The cost of treatment for the injured worker can exceed $1,000,000/case. Significant litigation fees, insurance increases, fines, and accident investigation costs can occur. This does not include work in progress loss or job layoffs as a result of the process interruption. These cumulative costs can exceed $10,000,000. Back to top

Q. What can I do to reduce my risk to arc flash exposure?

A. Preventive maintenance, worker training, and an effective safety program can significantly reduce arc flash exposure. Preventive maintenance should be conducted on a routine basis to ensure safe operation. As part of a preventive maintenance program, equipment should be thoroughly cleaned and routine inspections should be conducted by qualified personnel who understand how to uncover loose connections, overheated terminals,discoloration of nearby insulation, and pitted contacts. A comprehensive preventive maintenance plan should also include:

Using corrosion resistant terminals and insulate exposed metal parts if possible
Sealing all open areas of equipment to ensure rodents and birds cannot enter
Verifying that all relays and breakers are set and operate properly

Q. Why are the standards for arc flash changing?

A. Arc Flash first became an industry concern in the early 1980’s with the publication by Ralph Lee titled, “The Other Electrical Hazard: Electric Arc Blast Burns.” Similar studies illustrated that too many people were sufferinginjuries as a result of arc flash incidents. Therefore, early adopters in the petrochemical industry took steps to establish the first set of practices designed to better protect employees and electrical contractors. Soon other industries recognized the need for additional protection against arc flash hazards. These new industry standards developed by the NEC and others were designed to protect electrical workers from the hazards of shock, electrocution, arc flash, and arc blast. Back to top

Q. What is a calorie?

A. A calorie is the energy required to raise one gram of water one degree Celsius at one atmosphere. The onset of second-degree burns will occur at 1.2 calories per centimeter squared per second. One calorie per centimetersquared per second, can be equal to holding your finger over the tip of the flame of a cigarette lighter for one second.

Q. Are all arcs equal?

A. No. Arcs vary in intensity and duration. The intensity is measured in calories per centimeter squared per second as described above and is dependent on fault current magnitude. The duration of the arc depends on how quickly the protective device interrupts the fault. Intensity and duration must be known to calculate the incident energy to which a worker could be exposed. From this information, the proper personal protective equipment (PPE) can be specified. Back to top

Q. How do you determine what PPE is required?

A. In order to select the proper PPE, incident energy must be known at every point where workers may be required to perform work on energized equipment. These calculations need to be performed by a qualified personsuch as an electrical engineer. All parts of the body that may be exposed to the arc flash need to be covered by the appropriate type and quality of PPE. Proper PPE can include Flame Resistant clothing, hardhat, hood,face shield, safety glasses, gloves, shoes, etc. depending upon the magnitude of the arc energy.

Q. What standards regulate arc flash hazards?

There are four main regulations governing arc flash. They include:

OSHA Standards 29-CFR, Part 1910. Occupational Safety and Health Standards. 1910 sub part S (electrical) Standard number 1910.333 specifically addresses Standards for Work Practices andreferences NFPA 70E.
The National Fire Protection Association (NFPA) Standard 70 “The National Electrical Code” (NEC) contains requirements for warning labels
NFPA 70E provides guidance on implementing appropriate work practices that are required to safeguard workers from injury while working on or near exposed electrical conductors or circuit parts thatcould become energized.
The Institute of Electronics and Electrical Engineers (IEEE) 1584Guide to Performing Arc-Flash Hazard Calculations. Back to top

Q. Who enforces these new standards?

A. OSHA is an enforcer of safety practices in the workplace. OSHA 1910.132(d), and 1926.28(a) states that the employer is responsible to assess the hazards in the work place, select, have, and use the correct PPE, and document the assessment. Though OSHA does not, per se,enforce the NFPA 70E standard, OSHA considers the NFPA standard a recognized industry practice and the administration’s field inspectors carry with them a copy of the NFPA 70E and use it to enforce safety procedures related to arc flash.

The employer is required to conduct hazard assessment in accordance with 29CFR1910.132(d)(1). Employers who conduct the hazard/risk assessment, and select and require their employees to use PPE, as stated in the NFPA 70E standard, are deemed in compliance with the Hazard Assessment and Equipment Selection OSHA Standard.

Electrical inspectors across the country are now enforcing the new labeling requirements set forth in the 2002 National Electric Code (NEC).

Q. What data is required to be on the new arc flash warning labels?

A. 110.16 only requires the label state the existence of an arc flash hazard. But for obvious reasons the industry has adopted as a de facto standard, labels that also include the following information:

Flash Protection Boundary
Incident energy at 18” expressed in cal/cm2
PPE required
Voltage shock hazard
Limited shock approach boundary
Restricted shock approach boundary
Prohibited shock approach boundary

Q. How do I determine the flash protection boundary?

A. The flash protection boundary is based on voltage, available short-circuit current and predicted fault duration. The NFPA 70E provides FOUR acceptable methods of determining flash protection boundary:

Analysis based on IEEE 1584
Analysis based on NFPA 70E 130.3(A) and Annex D
Simplified Two-Category FR Clothing System, Annex H
The hazard risk categories provided by Table 130.7(C)(9)(a)

Q. Which method of determining flash protection boundary is the best?

A. All of the known methods have some limitations. The tables provided by NFPA may be easy to use but they are based on typical equipment and systems and are only approximations. They also require information from an up to date short circuit and coordination study. Detailed analysis yields different results than the tables do. Therefore, whatever standard you use, it is necessary to understand its limitations. Years of industry application experience have resulted in the IEEE1584 standard referenced in NFPA 70E as being the preferred method for a comprehensive arc flash analysis. Back to top

Q. What is the difference between NFPA 70E and IEEE 1584 calculations?

A. NFPA 70E method estimates incident energy based on a theoretical maximum value of power dissipated by arcing faults. This is believed to be generally conservative. In contrast, IEEE 1584 estimates incident energy with empirical equations developed from statistical analysis of measurements taken from numerous laboratory tests.

Q. How does an effective preventive maintenance program reduce arc flash hazards?

A. A preventive maintenance program on protective devices is recommended as part of the arc flash program. All arc flash calculations require the arc clearing time in order to determine incident energy and establish the flash protection boundary. The clearing time is derived from the engineering coordination study based on what the protective devices are supposed to do. If maintenance and testing is not performed it could result in extended clearing times, unintentional time delays, open or shunted current transformers, open coils or dirty contacts. All of these factors could cause the results of flash hazard analysis to be inaccurate—causing the flash protection boundary to potentially be inaccurate. This could also affect the recommendations for the proper PPE. For this reason, it is recommended that facilities adopt NFPA 70B Recommended Practice for Electrical Equipment Maintenance. Back to top

Q. What is a flash hazard?

A. A flash hazard is defined in NFPA 70E as a dangerous condition associated with the release of energy caused by an electric arc.
.

Q. Why should I have a short circuit and protective device coordination study performed prior to the arc flash hazard analysis?

A. Arc flash calculations completed in conjunction with short circuit calculations and protective device coordination help ensure that the most accurate arc flash hazard results are achieved. Arc flash hazard boundaries are based on voltage, available short-circuit current and predicted fault duration derived from these analyses. Back to top

Q. What is the flash protection boundary?

A. The flash protection boundary is the distance from the arc source at which the potential incident heat energy from an arcing fault falling on the surface of the skin is 1.2 calories/cm2.

Q. What is “Limited Approach Boundary”?

A. The limited approach boundary defines a boundary around exposed live parts that may not be crossed by “unqualified” person unless accompanied by “qualified” persons. Back to top

Q. What is “Restricted Approach Boundary”?

A. The restricted approach boundary is the area near the exposed live parts that may be crossed only by “qualified” persons using appropriate shock prevention techniques and equipment.

Q. What is “Prohibited Approach Boundary”?

A. The prohibited approach boundary is the area near exposed live parts that may be crossed only by “qualified” persons using the sameprotection as if direct contact with live parts is planned. This is defined by the nominal voltage. Back to top

Q. What is the definition of a “qualified” person?

A. A qualified person is one who has received documented training in the hazards of working on energized equipment in general, and has been trained in the hazards of the particular equipment to be serviced. Training must include the use and proper application of PPE. Back to top

Q. What data is required for a Short Circuit Analysis?

A. Typical data that is required for a short circuit analysis includes the equipment type, voltage, withstand rating, MVA/KVA, impedance, X/R ratio, and phases/connection.

Q. What data is required for Protective Device Coordination Study?

A. For relays you will need to determine the relay type, CT ratio, pickup (tap) setting, delay type (curve) and setting time dial. For fuses you’ll need the fuse type, amp rating, voltage, and peak let-through current. For circuit breakers you will need the circuit breaker type, fault clearing time, pickup setting, delay curve, and delay setting. Back to top

Q. What is an Arc Flash Study/Analysis?

A. An Arc Flash Study/Analysis is an engineering study that determines the amount of current that could flow at any point in an electrical system, and the timing required for the nearest circuit protective device to operate to clear a fault.

Q. What data is required for an Arc Flash Study?

A. Depending on the method of calculation, you will need to determine the type of enclosure, gap between exposed conductors, grounding type, phases/connection, and working distance. Back to top

Q. What is the hazard/risk category?

A. The hazard/risk category is specified as a number representing the level of danger, which depends upon the incident energy. The category ratings range from 0 to 4 where category 0 represents little or no risk, and category 4 signifies the greatest risk. Above category 4 (>40 calories/cm²) all equipment is considered too dangerous to work on energized because of the tremendous pressure blast.

Q. When is it okay to work on “energized” or “live” equipment?

A. It is always preferable to work on de-energized equipment. However, OSHA regulations state in 1910.333 (a) that workers should not work on live equipment (greater than 50 volts) except for one of two reasons, 1) De-energizing introduces additional or increased hazards such as cutting ventilation to a hazardous location, or 2) Infeasible due to equipment design or operational limitations such as when voltage testing is required for diagnostics. When it is necessary to work on energized equipment you should follow safe work practices including assessing the risks, wearing proper PPE, and using the proper tools. Back to top

Q. How can equipment design impact arc flash hazards?

A. The incident energy exposure caused by an arc flash can be affected by the system configuration, system fault levels, and exposure time. System fault levels can be reduced by changing the system configuration to reduce available fault current, and by using current limiting devices such as fuses, breakers, and reactors. Using faster acting relays and trip devices can reduce arcing time or exposure time. A protective device coordination study should also be conducted to ensure proper device settings. Instantaneous relays could also improve clearing times, limiting the arc exposure time. Fuse ratings and characteristics should also be evaluated to determine if a smaller and/or faster fuse could be used to help reduce the exposure time.

Q. What is “incident energy”?

A. Incident energy is defined in NFPA 70E as, “the amount of energy impressed on a surface, a certain distance from the source, generated during an electrical arc event.” Back to top

Q. What is an “electrically safe work condition”?

A. An electrically safe work condition is defined as a state in which the conductor or circuit part to be worked on or near has been disconnected from energized parts, locked/tagged in accordance with established standards, tested to ensure the absence of voltage, and grounded if determined necessary.

Let Argo Electrical Services install your new Chandelier!

Fri, 05 Mar 2010 11:13:12 +0000

2008 Code Update

Tue, 02 Mar 2010 13:46:53 +0000

In 2008, The National Electrical Code upgraded it’s safety requirements for Electrical Panelboards in all Residential (Dwellings) to include Arc Flash Protection. The National Fire Protection Association states that ” Each year home electrical problems cause about 70,000 fires, resulting in 485 deaths and $868 million in property loss.”
A Panelboard Upgrade,including a Load Calculation, AFCI Breakers,a Whole House Surge Protector, and Smoke Alarms that are Up to Date and Operable, not only can you provide protection for your family and your property, you can invest in Peace of Mind! For minimal cost disaster can be avoided.

Power Surges More Info

Tue, 02 Mar 2010 13:46:19 +0000

Electrical power surges are a danger to your home and your possessions. Today, many appliances are controlled by electronic control circuits. These are especially susceptible to damage from electrical power surges. In the extreme cases, a major power surge can even cause a fire.

The most common cause of a major electrical power surge is a lightning strike. When lightning strikes on or near your home, it is seeking a way to ground. It will travel through all connected wires until it finds a ground, which is often your computer or other appliance. A power surge from lightning is very powerful and few appliances are made to withstand such power.

Another cause is a fault in the transmission lines from your electric provider. While generally not as strong as a lightning caused surge, it is still enough to kill your delicate electronic equipment or destroy data on your computer. Developing countries are particularly likely places to find these types of surges, but they can be from anywhere.

Static electricity generated inside your house, especially on very dry days, is another source. Scraping your feet on the carpet and then touching the appliance can be enough to cause damage. Sometimes older major appliances, such as refrigerators or air conditioners, generate a strong surge when their compressors are cycled in.

Individual surge protectors are required in most areas by the local code, but are mandatory usually only for areas in the house that are near water, such as sinks. This is why it’s a good idea to look into whole house surge protector systems. They are not as easy to find, and they should be professionally installed, but it’s worth the effort to protect your entire home.