Andhra Pradesh A Class Electrical Contractors Association POWER
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Harmonizing Volume-I
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Reg No.:790/2016
Power Newsletter For private circulation only
Issue-1
Oct to Dec 2017
EXECUTIVE COMMITTEE
Scientists Dream about doing GREAT THINGS. Engineers do them
President K. Leela Prasad 98481 93459, 98668 93459 leelaprasadk@yahoo.co.in
KIMIDI KALA VENKATA RAO
Vice President A.V.R. Sarma 98493 44181 sarma.engineers@gmail.com Secretary Y. Narayana Rao 9959922455 saeprojectsvsp@gmail.com Joint Seccretary D. Bala Subramanyam 9440406885 dbsolutions_power@yahoo.co.in Treasurer K. Satyanarayana 9885196808 katta.s2273@gmail.com
EXECUTIVE COMMITTEE MEMBER Mr. L. Eswara Rao 9394026180 juhieswar@gmail.com
Hon’ble Minister for Energy, Govt. of A.P
Message FROM THE PRESIDENTS DESK:
K. Leelaprasad
Dear Members,
President
In the combined state of Andhra Pradesh in the year 1996 Teluguanadu Electrical Contractors Association was formed with offices at Hyderabad. After the separation of Andhra Pradesh we have formed Andhra Pradesh A Class Electrical Contractors association to serve the 13 Districts of Andhra Pradesh Electrical Community. The association is a service oriented non profit organization for the benefit of licensed 'A' Grade Electrical contractors to maintain. a. Safety Standards d. Importance of life safety Electrical safety
b. Knowledge sharing c. Technical support e. Importance of Energy conservation
This is necessary in view of the rapid development in the Industrial sector, construction activities of High rise buildings and Our AP State Capital Amaravathi coming up with high rise buildings with State of the Art Technology requires un interrupted power supply and it is the necessity that the Electrical Systems standards are to be maintained.
Mr. A.V.S.D Prasad 9491934311 srihariele65@gmail.com
Country's power supply should be put to most efficient use in the best interest of the community at large.
Mr. K. Appa Rao 9949790938 ipssekharsri@gmail.com
For the growth of our Association spreading membership strength in all the districts of Andhra Pradesh we have to form district wise committees taking up of the activities to reach one and all in each district with motivation of dissemination of knowledge and day to day changes in the electricity Rules & safety Regulations.
Mr. S. Praveen Bharadhwaj 9490619966 kps.vizag@yahoo.co.in
This creates a platform to interact with Electrical Distribution companies engineering team and with directorate of Electrical safety department to keep abreast with latest Government orders and Electrical safety laws.
Mr. A. Appala Raju 9848415128 raa.kvps@gmail.com
ADVISORY COMMITTEE Mr. C.V. Raju 9885270210 apc_raju@yahoo.co.in Mr. Gurunadh Rao 9849365654 gurunadh@outlook.in Dr. K. Kumar Raja 098481 96678 kumarraja@kkumarrajaprojects.com
Andhra Pradesh A Class Electrical Contractors Association objective was to provide a platform for Electrical Community for furthering their knowledge to be at par with National & International standard's.
News letter can cover all technical activities of the Association and with this idea News letter thought come into existence Associations innovative thinking in conducting various types of Technical Seminars, workshops Technical presentations for its Members and exposure to Industrial products by way of Exhibitions for better understanding of Industrial products & practices.
Inside Association Launching
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Electrical Safety & Security Knowledge Article-1
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RESIDUAL CURRENT CIRCUIT BREAKERS (RCCBs) Knowledge Article-2
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EARTHING : IMPORTANT BUT NOT UNDERSTOOD WELL PART 1 Knowledge Article-3
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Andhra Pradesh A Class Electrical Contractors Association POWER
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Reg No.:790/2016
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Renewed Brand for Association Launched in August
Andhra Pradesh A Class Electrical Contractors Association is a voluntary nonprofit organization striving towards improvement of all critical elements of the Electrical Standards of work and Latest Safety Standards. The Association is inaugurated by Hon.Ble Minister for Energy Sri Kimidi Kala Venkata Rao at 10.30 AM today at Hotel Fortune Inn Sree Kanya and in his address to the Association members on the importance of Electricity and necessity of maintaining safety standards. The day to day in every walk of life from House to office to industry, entertainment Electrical supply is the basic necessity and it shall be stable and safe supply to carry out all the works without interruption.
the electrical installations. By fallowing standards in the Electrical Installation we can improve supply standards for the uninterrupted power supply for the progress of the Industry to boost up the production and producing good quality product. The Guest of Honour Sri P.Janardhan Reddy, Director of Electrical safety and
POWER SAFETY SERVICE
This makes every contractor to execute the electrical works giving importance to the Safety of life of the workmen working on
As a Societal Responsibility the Associaiton will spread the awareness among public in the usage of Electrical products for Energy conservation by using LED lamps and also suggeat them to install Solar PV panels on the rooftop of every domestic house for their usage and thus reducing the load on the Sub Stations and also government need not plan for generating stations to meet the demand. The Association will take up awareness programs on Electrical Safe usage of Equipment and Conservation among children by educating the school Children by conducting painting competitions and Elecution comptetion.
From Domestic to commercial and Industry safety standards have to be maintained for the safety of life, property and prosperity. The Guest of Honor Sri MM Nayak IAS CMD of APEPDC Ltd has appreciated for starting the Association to develop the knowledge and for exposure to latest products and standards among the members of the Association. The APEPDC Ltd., was committee to create awareness on the safe use of electricity.
strive towards improving the Electrical Standards in the execution of works, Conducting Technical Seminars, Product presentation Expo's and training programs for the upgradation of the knowledge of the Electrical Contractors ie., Members of the Associaiton.
CEIG of AP highlighted the importance of safety standards to be maintained for supply of safe power and life safety and without any property loss. He emphasized the Need of maintaining best earthing standards which plays vital role in the human safety. The President of the Association Mr.K.Leela Prasad has assured that the Associaiton will
M/s Cosul Neowatt and M/s Gloster Cables gave presentation on the latest Products manufactured by them for the knowledge of the members. The meeting was concluded by proposing vote of thanks by the Secretary Mr. Narayana Rao, was well attended by 150 members and committee members CVP Raju, AVR Sarma, Satyanarayana.
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Power Newsletter For private circulation only
Electrical Safety & Security Safety & Security are most important aspects of day to day life for the Human Life and property Electrical Supply Plays major Roll in every walk of life and use of Electricity has changed our life. Electrical safety plays major role to avoid electrical accidents.
Electrical Accidents - Statistics Almost 12 people die due to electrocution every day *42% of total fires occur due to electrical. 8% deaths that occur in Indian factories are due to electricity in India. 25% of all fires occur due to electricity (NFPA) The rapid growth in the modern world in commercial, industrial, comfort application, communications, Information Technology systems and Automation electricity plays a major role. Safety is of paramount importance in generation, transmission, distribution till the final usage of electrical energy to safeguard human life and property.. Engineers, Electrical technical staff and other professionals work with electricity in power generating station, transmission lines and sub stations, and industrial electrical installation can be dangerous. Safety measures have to be taken while attending installation works and maintenance work is utmost important.. Every person working on electrical supply shall be aware of the safety practices as per the following safety standards laid down.
Standards for safety 1. The Indian Electricity Rules, 1956, contain specific regulations to be adhered to in the supply and use of electrical energy. 2. Central Electricity Authority (Measures relating to safety and Electric Supply ) Regulations, 2010 3. Indian Electricity Act, 1910 4. Indian Electricity Rules, 1956 (SUPERCEDED) 5. In order to rationalize these practices, India's first National Electrical Code, formulated in 1985
- K. Leele Prasad MEP Consultant
6. Electricity Act 2003 7. Energy Conservation Act, 2001 8. Electrical Installations Sectional Committee, ETD20 9. Electrical Installation should be carried out in accordance with the Indian Electricity Rules, 1956 (SUPERCEDED) 10.Recommendations concerning safety and related matter 11.General safety procedures and practices in electrical work 12.Additional precautions for special environmental conditions like explosive and active atmosphere. 13.National Electrical Code (NEC2011) (SUPERCEDED)
Domestic dwellings Office buildings Shopping an commercial centers Institutions Recreation and other public premises Medical establishments Hotels Sports buildings Industrial premises Temporary and permanent outdoor installations Agricultural premises Installations in hazardous areas Solar Photovoltaic installations
NEC 2011 APPLIES TO THE FOLLOWING INSTALLATIONS Standby generating plants Building substations
Application of a safety standard is intended to reduce the risk of injury or damage due to : * Electric shock * Energy related hazards * Fire * Heat related hazards * Mechanical hazards * Radiation * Chemical hazards
Ten Important Tips to be followed for Electrical Safety 1. Follow Lockout and Tagout dures.
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2. Use proper personal protective equipment before attending electrical work use Right tool for Right task. 3. Double earthing has been provided or not with proper earth electrode and earth resistance shall be below 1.0 ohm. 4. Provided proper RCCB's or not 5. Follow Earth strip sizes as per I.S. 6. Check whether proper protective Relays and Releases are provided in the Breakers with proper settings. 7. Check whether proper lugs are used or not with proper crimping. 8. Check whether proper cable glands are provided or not with proper earthing. 9. Check for proper sizing of the Bus Bars as per I.S. Check for Tightening of all Bus Bar connections and cable connections in the panel. 10. Check whether proper sizes of cable and wires with proper laying, spacing, routing and Dressing is followed.
Approximately half a mili - ampere can cause a reaction in persons in good health and may cause injury indirectly due to involuntary reaction. Electrical safety plays major role in saving Human life and property loss due to electrical fires. Every typical industry has its own safety practices depending on the type of the installation, whether it is Mall, Multiplex, Hotels, Hospital, Residential and Commercial application, Oil Storage and Refineries and Pharma Industries standard of safety measures to be taken WHY Electrical SAFETY AND PROPERTY PROTECTION ? 1.Why Electrical Safety? * Sometimes it is easy to forget just how dangerous electricity can be * Electricity can cause serious injuries or even death * It takes very little electricity to cause harm * Lack of safety can cause serious electrical HAZARDS. 2. Effects on the Human Body depends on * Current and Voltage * Resistance * Path through body Duration of shock 3.Electrical Dangers * Electrical Shock * Electrocution ( death due to electrical shock) *Burns *Falls *Arc flash and Arc Blast * Explosions * Fires
Andhra Pradesh A Class Electrical Contractors Association POWER
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Reg No.:790/2016
RESIDUAL CURRENT CIRCUIT BREAKERS (RCCBs): RCCBs also called as ELCBs ( earth leakage circuit breakers) or GFCIs ( Ground fault Circuit Interrupters in USA ) are supposed to be used in all Electrical installations as per Rule 42 of "MEASURES RELATING TO SAFETY AND ELECTRIC SUPPLY REGULATIONS - 2010" ( Which replaced IE Rules 1956) states as given below
trip the breaker. These devices are Equipment specific and protect only that equipment. The diagram of Voltage operated ELCB is given below
" Supply of electricity to all installations other than <250v, 5kw and which do not attract provisions of regulation 54 ( Rule 54 deals with Supply to X Ray & High Frequency applications), shall be controlled by a ELCB to disconnect supply instantly on occur- Working Principle of RCCBs . rence of earth fault/leakage The working principle of current earth leako Provided such Earth leakage protection age circuit breaker or RCCB is different and devices are not required for OH lines hav- more sensitive than ELCB. In RCCB, one CT ing protective devices which are effective- core is energized from both phase wise and ly bonded to neutral of supply transformer neutral wire. The relay coil is connected with & conforming to regulation 73 another third winding wound on the CT core o ( Regulation 73 deals with safety & pro- as secondary. The terminals of this winding tective devices which is given below for are connected to a relay system. understanding Single Phase Residual Current ELCB: " Every OH line which is not being suspendThe polarity of the phase winding and neued from a dead bearer wire, not being covtral winding on the core is so chosen that, in ered with insulating material, and not being normal condition magnetic flux of one winda trolley wire, erected over a part of street or ing opposes that of another. In normal operpublic space or factory shall be protected ating conditions, the current goes through with earth guarding the phase wire is returned via neutral wire " owner of every OH line shall ensure that it and both currents are equal and hence the cannot be ascended by unathorized per- fluxes are also equal and opposite in magnisons) tude and resultant Flux is Zero. Types of Earth leakage Protection Devices : When any earth leakage occurs in the equipThere are two types of Leakage sensing ment, there may be part of phase current possible in Electrical circuits ie Voltage sens- passes to the earth, through the leakage ing and Current sensing. Voltage sensing path instead of returning via neutral wire. Devices are usually called ELCBswhich are Hence the magnitude of the neutral current no more used in any installations and passing through the RCCB is not equal to Current sensing devices are called RCDs ( phase current passing through it which Residual Current Devices ie without any trip- causes resultant flux to be more and this will ping device), RCCBs, RCBOs( RCCB + MCB combination device)
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- V. Srinivas,CEO Synergy Infra Consultantâ&#x20AC;&#x2122;s Pvt. Ltd.
sum of all phase currents is equal to zero and hence the relay will not operate. Even in case of unbalance circuits, the Neutral current is equal to Sum of all phase currents and hence resultant flux is nullified. But in case of leakage in any one phase to ground, the Neutral current is not equal to vector sum of phase currents which causes current to flow in Core balance CT which in turn trips the circuit breaker Rating of RCCB :The effects of current on Human body in normal condition of body with normal body resistance was established by IEC and is reproduced below. However it was established that any current more than 30mA for a duration beyond 30mS is fatal to a person. Hence the sensitivity of RCCBS shall be 30mA for human protection and 100mA for property protection from fire. IS12640: 2008 ( which is
derived from IEC 61008) is the code related to RCCBs Part 1 Deals with RCCBS and Part 2 deals with RCCB with Over current protection ie RCBOs. They may be referred to for thorough understanding of requirements and specifications.
Working Principle of ELCB : One terminal of the relay is connected to the body of the equipment to be protected against earth leakage and other terminal is connected to the earth directly. If any insulation failure occurs or bodyof the equipment becomes live due to a fault, there will be a voltage difference appears across the terminal of the coil connected to the equipment body and earth. This voltage difference produces a current to flow the relay coilWhich is sensed as Earth leakage and if exceed a pre determined value, the current through relay
induce a current in Core balance CT which trips the breaker. Three Phase Residual Current Circuit Breaker : Even in case of three phase circuits, when loads are balanced, the vector
Log-log graph of the effect of alternating current Iof duration T passing from left hand to feet as defined in IEC publication 60479-1. AC-1: imperceptible AC-2: perceptible but no muscle reaction AC-3: muscle contraction with reversible effects AC-4: possible irreversible effects AC-4.1: up to 5% probability of ventricular fibrillation AC-4.2: 5-50% probability of fibrillation AC-4.3: over 50% probability of fibrillation
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Power Newsletter For private circulation only
EARTHING : IMPORTANT BUT NOT UNDERSTOOD WELL- PART 1 Earthing is the most important part of electrical system but not understood well. Earthing is required to protect the personnel from shock hazards, equipment from failures and property from Fires. It has become a common practice for all equipment vendors to ask for separately two earthing stations to protect their equipment. In a multi storeyed Office environment with 100 different offices or in a Health care facility having hundreds of Equipment, if two separate earth stations are required for each equipment, an earthing farm is Fig1 : Direct Contact: required. Some ideas about proper earthing system are brought out in the following paragraphs for easy understanding Types of earthing: Earthing is required for connection to Neutral points of three phase Equipment like Transformers, Generators and UPS systems to derive a neutral for single phase applications which is called "System earthing/ System Grounding". System earthing is required to balance voltages in all three phases, serves as a fixed reference point and also used to measure the fault Fig2 : Indirect Contact: currents for Relay operation.. The types of System earthing, ie Solid ground, There is a possibility that some of the metal Resistance ground, Coil ground will be dis- conductive parts, not related to electrical cussed subsequently which are dependant equipment, but running close to electrical on Fault currents to be measured for systems may also become charged due to induction or due to accidental contact with Protection and Relaying applications. electrical equipment. This situation may Earthing required to connect bodies of give a mild / heavy shock to personnel and electrical equipment to protect personnel hence all such metal conductive parts like from Shock hazards in case of abnormal Water pipes, Fire pipes, Steel structures conditions ie. leakage to body of equip- including metal windows etc, close to elecment due to insulation failure or under fault. trical equipment shall also be connected to All the bodies shall be connected to earth. Equipmentearthing by earthing conductor. This earthing is called "Equipment This is called "Bonding" Earthing/ Grounding". It can be seen from Fig1 below with direct contact with electrical system without earthing, the fault current could reach upto 100mA and a person may die. As in second case, if the person touches body of earthed equipment, the fault current is reduced to 40Ma and hence less fatal.
- V. Srinivas,CEO Synergy Infra Consultantâ&#x20AC;&#x2122;s Pvt. Ltd.
bonded, from personnel safety point. All the above systems of earthing like System earthing, Equipment earthing and Bonding shall be connected to a common earth grid for safety of personnel to avoid undue potential differences between various Earthing systems, which is called Equipotential bonding. The equi potential Earthing layout for a hospital suggested in NEC 2011 is given below All the above systems of earthing like System earthing, Equipment earthing and Bonding shall be connected to a common earth grid for safety of personnel to avoid undue potential differences between various Earthing systems, which is called Equipotential bonding. The equi potential Earthing layout for a hospital suggested in NEC 2011 is given below
For the Protection of structures against Lightnings, down conductors shall be connected to an Earthing system Recently many people started talking about Safe earth, Clean earth which are not defined in any of the Codes or standardsIndian or International. It is also not advisable to have different earthing grids, not
Components of earthing : The main components of Earthing are Earth electrodes, and Earth conductors.
Andhra Pradesh A Class Electrical Contractors Association POWER
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Earth Electrodes : There are various types of Electrodes ie Pipe, Plate, Strip types electrodes, material either of Copper, CI or GI. The material of construction of electrodes shall not make any difference but shall be chosen from resistance to corrosion, longevity of electrode etc .
Even columns are allowed as Down conductors for Lightning Protection as per IS/IEC 62305, provided electrical continuity is maintained or with top to bottom resistance less than 0.2 ohms. As per Safety Guidelines 2010 for Electrical dsitrbuton systems by CEA, min two earth stations shall be provided for Three phase systems and one for single phase systems for Body earthing. System earthing is not allowed anywhere other than near Transformer. If the same is allowed at any point, an isolation transformer shall be used with proper protection system
The earth resistance shall depend on Earth resistivity, Contact area of Electrode with earth and length of electrode in earth. It is calculated as R= Pl/A, where P = Resistivity of soil, l= Length f electrode, A= area of electrode If the area of cross section in contact with earth increased like in case of Plate electrode, the earth resistance is reduced. Also a long strip running for One Km, at 300400mm depth in a hilly terrain, where digging is not possible, has yielded less than 1 ohm resistance. It is observed that many people go for drillng bore holes in rocky terrain to achieve low resistance, but it may not give any good result since soil resistivity is very high, unless there is a water table beneath that. It is no use suggesting to provide two earth stations for equipment without knowing how much resistance is obtained by each electrode. It is important to understand the Soil resistivity before designing an earthing system using Wenner Four electrode configuration so that the desired resistance can be obtained. Usually rocky or sandy terrain will have very high resistivity in the order of 1000-2500 ohm-m, where as fertile land may have as low as 5-10 ohm-m. By use of Salts and Moisture, the resistivity can be reduced but salts or moisture are required to be added at regular intervals to maintain the resistance. High resistance may not offer desired protection. IEEE 80 also recognises certain soil enhancement compounds which retain moisture for a long duration. However it is also better to look at Earth grid or Direct driven rods by designing for the existing Soil resistivity so that there is no maintenance required and safe earthing can be offered over a long period.
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Earth Conductors : Earth conductors could be any type of material but shall be chosen from resistance to corrosion, longevity of electrode etc similar to Electrodes. Aluminum strips are not suggested for within ground. The conductor shall be sized to handle the fault current for duration of fault within which breakers isolate the power supply
It may be interesting to that RCC in the buildings has a Resistivity of around 100 ohm-m and can work like soil. Reinforcement in Buildings can be used for Earthing and the same is shown below, extract from IS 3043
As per IS 3043, the earthing conductors shall be provided as follows a. For phase conductors upto 16sq.mm, the earthing conductor also shall be 16sq.mm b. For phase conductors >16, <35 sq.mm the earthing conductor also shall be half of phase c. For phase conductors >35 sq.mm , the earthing conductor shall be workedout based on fault current from the following formula I/S= k/sqrt't' Where I= Fault current in Amps, S= Cross sectional area in sq.mm, toperating time of breaker in seconds, k= Constant ( Copper : 226, Aluminum : 148, Steel : 78)
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For private circulation only
About us Our Association is a service oriented & nonprofit organization formed for the benefit of Licensed A Grade Electrical Contractors in Andhra Pradesh. Main Aims and Objectives of the Association are : Country's power supply should be put to most efficient use in the best interest of the community at large. With this in view, the Association will be regularly organise Seminars and Exhibitions. Helping Members to acquire knowledge and lending a helping hand in their profession.
The Association is also planning for publishing of HAND BOOKS and Monthly NEWSLETTER dealing with general and specific problems in the installation and use of electric devices for safety and conservation of Energy. Our NEWSLETTER has been planned to have wide circulation throughout India, to reach other VIP's also in addition to our own members. Our NEWSLETTER will be useful for power professionals to update their knowledge and share the experiences. It covers wide range of topics starting from electrical data to new technologies in power system. We are also planning for coordinating with the Electrical Inspectorate, Government of Andhra Pradesh for forwarding the various Circulars to our members pertaining to rules and regulations.
WHY JOIN APACECA? 1. You can keep yourself abreast with the latest Government and Electricity Board orders pertaining to Electrical Contracting field.
Membership Fee:
2. You can update your knowledge attending the seminars organized by our Association. You can also effectively make your contribution.
1 Year Rs.1,200/-
3. By reading the technical articles published in our monthly News letter, you can keep track of the latest developments in the field. The Association is also periodically publishing HAND BOOKS and Monthly NEWSLETTER dealing with general and specific problems in the installation and use of electric devices for safety and conservation of Energy.
10 Years Rs.8,000/Cheque or DD in favour of Andhra Pradesh A Class Electrical Contractors Association, payable at Visakhapatnam
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4. Your views about various issues faced by contracting fraternity can be conveyed effectively to the various Government and EB authorities by the Association for relief and solution. Any Joint representation by Association has a better chance of consideration by concerned authorities rather than individual representation.
5 Years Rs.5,000/-
Andhra Pradesh A Class Electrical Contractors Association POWER
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SAFETY
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Reg No.:790/2016
#49-52-1/7A, Santhipuram, Visakhapatnam- 530 016. Andhra Pradesh, India Tel: 0891-2798675, 98668 93459. Email:apacecassociation@gmail.com This News Letter for In-house private circulation only, Edited and Published by Andhra Pradesh A Class Electrical Contractors Association #49-52-1/7A, Santhipuram, Visakhapatnam- 530 016. Andhra Pradesh, India