Electricity is the best friend and worst enemy Gobind Ajwani Marketing Manager www.alfredkim.net

Electrical Safety ----- Protect People & Property Extreme care, therefore, is required in Design, Construction, Operation, Maintenance and Utilization of Electrical Equipment and Installations with maximum attention to Safety. Safety considerations primarily concern the following : Basic Equipment for generation, transmission and Utilization. Non-electrical items of plant and Machinery located in the vicinity of Electrical Equipment. Operating Personnel. General Public.

INDIAN ELECTRICITY RULES- Let us review the important rules to get proper insight into safety aspects Rule 29 : Construction, installation, protection, operation and maintenance of electric supply lines and apparatus. All electric supply lines and apparatus shall be sufficient rating for power, insulation and estimated fault current and of sufficient mechanical strength for the duty which they may be required to perform under the environmental conditions of installation and shall be constructed, installed, protected, worked and maintained in such a manner as to ensure safety of human beings, animals and property. 1. Save as otherwise provided in these rules, the relevant code of practice of the Bureau of Indian Standards including National Electrical Code, if any, may also be followed to carry out the purposes of this rule and in the event of any inconsistency the provision of these rules shall prevail. 2. The material and apparatus used shall conform to the relevant specifications of the Bureau o Indian Standards where such specifications have already been laid down.

Rule 30 : Service lines and apparatus on consumer’s premises. The supplier shall ensure that all electric supply lines, wires, fittings and apparatus belonging to him or under his control which are on consumer’s premises, are in a safe condition and in all respects fit for supplying energy and the supplier shall take due precautions to avoid danger arising on such premises from such supply lines, wires, fittings and apparatus. 2. Service-lines placed by the supplier on the premises of a consumer which are underground or which are accessible shall be so insulated and protectetd by the supplier as to be secure under all ordinary conditions against electrical, mechanical, chemical or other injury to the insulation. 3.The consumer shall, as far as circumstances permit, take precautions for the safe custody of the equipment on his premises belonging to the supplier. 4. The consumer shall also ensure that the installation under his control is maintained in a safe condition.

Rule 31 : Cut-out on consumer’s premises : 1. The supplier shall provide a suitable cutout in each conductor of every service-line other than an earthed or earthed neutral conductor or the earthed external conductor of a concentric cable within a consumer’s premises, in an accessible position. Such cut-out shall be contained within an adequately enclosed fireproof receptacle. Where move than one consumer is supplied through a common service-line, each such consumer shall be provided with an independent cut-out at the point of junction to the common service. 2. Every electric supply line other than the earth or earthed neutral conductor of any system or the earthed external conductor of a concentric cable shall be protected by its owner.

Rule 32 : Identification of earthed and earthed neutral conductors and positions of switches therein. Where the conductors include an earthed conductor of a two-wire system or a conductor which is to be connected thereto, the following conditions shall be compiled with : 1. An indication of a permanent nature shall be provided by the owner of the earthed neutral conductor, or the conductor which is to be connected thereto, to enable such conductor to be distinguished from any live conductor. Such indication shall be provided – a. where the earthed or earthed neutral conductor is the property of the supplier, at or near the point of commencement of supply; b. where a conductor forming part of a consumer’s system is to be connected to the supplier’s earthed or earthed neutral conductor, at the point where such connection is to be made; c. in all other cases, at a point corresponding to the point of commencement of supply or at such other points as may be approved by an inspector or any officer appointed to assist the inspector and authorized under sub-rule (2) of rule 4A.

2. No cut-out, link or switch other than a linked switch arranged to operate simultaneously on the earthed or earthed neutral conductor and live conductors shall be inserted or remain inserted or remain inserted in any earthed or neutral earthed neutral conductor of a two-wire system or any earthed or earthed neutral conductor of a multi-wire system or in any conductor connected thereto with the following exceptions : A link for testing purposes, or B. switch for use in controlling a generator or transformer.

1. The supplier shall provide and maintain on the consumer’s premises for the consumer’s use a suitable earthed terminal in an accessible position at or near the point of commencement of supply as defined under rule 58. Provided that in the case of medium, high or extra-high voltage installation the consumer shall, in addition to the aforementioned earthing arrangements, provide his own earthing system with an independent electrode. Provided further that the supplier may not provide any earthed terminal in the case of installations already connected to his system on or before the date to be specified by the State Government in this behalf if he is satisfied 2. The consumer shall take all reasonable precautions to prevent mechanical damage to the earthed terminal and its lead belonging to the supplier 3. The supplier may recover from consumer the cost of installation on the basis of schedule of charges notified in advance and where such schedule of charges is not notified, the procedure prescribed, in sub-rule (5) of rule 82 will apply. Rule 33 : Earthed terminal on consumer’s premises :

1. The supplier shall provide and maintain on the consumer’s premises for the consumer’s use a suitable earthed terminal in an accessible position at or near the point of commencement of supply as defined under rule 58. Provided that in the case of medium, high or extra-high voltage installation the consumer shall, in addition to the aforementioned earthing arrangements, provide his own earthing system with an independent electrode. Provided further that the supplier may not provide any earthed terminal in the case of installations already connected to his system on or before the date to be specified by the State Government in this behalf if he is satisfied 2. The consumer shall take all reasonable precautions to prevent mechanical damage to the earthed terminal and its lead belonging to the supplier 3. The supplier may recover from consumer the cost of installation on the basis of schedule of charges notified in advance and where such schedule of charges is not notified, the procedure prescribed, in sub-rule (5) of rule 82 will apply. Rule 33 : Earthed terminal on consumer’s premises :

Where bare conductors are used in a building, the owner of such conductors Shall. a. ensure that they are inaccessible; b. provide in readily accessible position switches for rendering them dead b. whenever necessary; and c. take such other safety measures as are considered necessary by the inspector. Rule 34 : Accessibility of bare conductors.

The owner of every medium, high and extra-high voltage installation shall affix permanently in a conspicuous position a danger notice in Hindi or English and the local language of the district, with a sign of skull and bones of a design as per the relevant ISS No. 2551 on – a. every motor, generator, transformer and other electrical plant and equipment together with apparatus used for controlling or regulating the same; b. all supports of high and extra-high voltage overhead lines which can be easily climbed upon without the aid of ladder or special appliances; Explanation :- Rails, tubular poles, wooden supports, reinforced cement concrete poles without steps, I-sections and channels, shall be deemed as supports which cannot be easily climbed upon for the purposes of this clause. c. Luminous tube sign requiring high voltage supply, X-ray and similar high-frequency installations; Provided that where it is not possible to affix such notices on any generator, motor, transformer or other apparatus, they shall be affixed as near as possible thereto; or the Word ‘Danger’ and the voltage of the apparatus concerned shall be permanently painted on it. Provided further that where the generator, motor, transformer or other apparatus is within an enclosure one notice affixed to the said enclosure shall be sufficient for the purposes of this rule. Rule 35 : Danger Notices :

1. Before any conductor or apparatus is handled, adequate precautions shall be taken by earthing or other suitable means, to discharge electrically such conductor or apparatus, and any adjacent conductor or apparatus if there is danger therefrom, and to prevent any conductor or apparatus from being accidentally or inadvertently electrically charged when persons are working thereon. Every person who is working on an electric supply line or apparatus or both shall be provided with tools and devices such as gloves, rubber shoes, safety belts, ladders, earthing devices, helmets, line testers, hand lines and the like for protecting him from mechanical and electrical injury. Such tools and devices shall always be maintained in sound and efficient working conditions. 2. No person shall work on any live electric supply line or apparatus and no person shall assist such person on such work, unless he is authorized in that behalf, and take sthe safety measures approved by the Inspector. 3. Every telecommunication on supports carrying a high or extra-high voltage line shall, for the purpose of working thereon, be deemed to be a high voltage line. RULE 36 : Handling of electric supply lines and apparatus :

RULE 37 : Rules 37 to 41A : These appertain to provisions in respect of supply to vehicles, cranes etc, cables for portable or transportable apparatus, cables protected by bituminous materials, street boxes and distinction of different and multiple feed installations. RULE 37 : Rules 43 to 46 : These concern stipulations regarding protective equipment like fire buckets, fire extinguishers, First-aid boxes, gas masks, Instructions for restoration of persons suffering from electric shock, intimation of accidents, precautions to be adopted by consumers, owner occupiers, electrical contractors, electrical workmen and suppliers along with provisions for periodical inspection and testing of installations. RULE 61 : Connection with earth. These rules lay down the requirements of connection with earth of systems at low voltage in cases where the voltage exceeds 125 volts and of systems at medium voltage.

RULE 61A : Earth leakage protective device The supply of energy to every electrical installation other than low voltage installation below 5 KW and those low voltage installations which do not attract provisions of Section 30 of the Indian Electricity Act, 1910, shall be controlled by an earth leakage protective device so as to disconnect the supply instantly on the occurrence or earth fault or leakage of current. Provided that the above shall not apply to overhead supply lines having protective devices which are effectively bonded to the neutral of supply transformers and conforming to Rule 91 of IE Rules,1956.

Application of Earthing • Allow zero potential to supply system • Provide zero connection for Neutral • Protect human against lightning and earth fault condition • Protect the premises against lightning and earth fault condition • Provide low resistance and safe path for lightning and fault current • All metallic enclosure and extraneous conductive parts are at equipotential • LV System Earth • Equipment Earth • Clean Earth for signaling and noise • Create equipotential platform Electrical Earthing is most neglected part of the electrical safety for people and property Let us discuss What is Earthing?

• Reference to IS3043 – 1987 Reaffirmed 2006 • “ Earth” means the Ground, reference zero potential • Rely on the system earth to maintain the system voltage and normal voltage supply • Equipment earth connects all non-conductive parts to protect human against electric shock • Class I protection – use of barrier/insulation and connection of protective conductor to equipment metallic enclosure in order to protect against electric shock • Class II protection – beside of the basic insulation, addition layer of insulation apply to the enclosure. Therefore no extraneous conductive part. The additional layer is independent to the basic insulation so that under failure of basic insulation, it offers additional protection Glossary

Reference to IS3043 – 1987 Reaffirmed 2006 • “ Earth” means the Ground, reference zero potential • Rely on the system earth to maintain the system voltage and normal voltage supply • Equipment earth connects all non-conductive parts to protect human against electric shock • Class I protection – use of barrier/insulation and connection of protective conductor to equipment metallic enclosure in order to protect against electric shock • Class II protection – beside of the basic insulation, addition layer of insulation apply to the enclosure. Therefore no extraneous conductive part. The additional layer is independent to the basic insulation so that under failure of basic insulation, it offers additional protection Glossary

Reference to IS3043 – 1987 Reaffirmed 2006 • “ Earth” means the Ground, reference zero potential • Rely on the system earth to maintain the system voltage and normal voltage supply • Equipment earth connects all non-conductive parts to protect human against electric shock • Class I protection – use of barrier/insulation and connection of protective conductor to equipment metallic enclosure in order to protect against electric shock • Class II protection – beside of the basic insulation, addition layer of insulation apply to the enclosure. Therefore no extraneous conductive part. The additional layer is independent to the basic insulation so that under failure of basic insulation, it offers additional protection Glossary

• Supply System – Neutral Earth • System Earth • Electrical Safety Earth • Lightning Earth • Generator Earth • Protection Earth (i.e. surge arrestor) • Telecom / Computer Earth • Shielding Earth • Integrated Earthing System (Advocated) • Electrostatic Earth (Clean Room / Hospital) • Cathodic protection (prevent rusty) Types of Earthing

• Equipment Earth : Path for fault current, lower touch voltage, protection against electric shock • Lighting Earth : Low resistance path to diverse the current under lightning attack • Telecom Earth : Signal Earth, reduce noise and interference, stabilize DC supply voltage and prevent electric shock • Computer Earth : reduce interference, maintain supply voltages Functions of Earth

• Two Alphabetic system description • First Alphabet – arrangement at Supply side – T represents system directly earthed, multi-earthed – I represents live part and earth path are separated, single point earthed through high impedance • Second Alphabet – arrangement at Consumer side – T represents extraneous parts directly earthed, the earth point independent from Supply side – N represents extraneous parts connected to the protective conductor of supply • TN systems have two category: – S protective conductor and neutral conductor are two wires – C protective conductor and neutral conductor are the same conductor Earthing System

TN-S ‧ protective conductor and neutral conductor are independent • All exposed metallic part connected with protective conductor PE • System Characteristics: – Low earth fault loop impedance – High earth fault current • Advantages: earth fault protection device operates faster; allow multi point earth, better earthing continuity; minimize the use of earth fault relay because of low earth fault loop impedance • Disadvantages: high earth fault level; under earth fault condition, low power factor (high inductance of long cable) Earthing System

Earthing System

TN-C ‧ protective conductor and neutral conductor are combined into one • All exposed conductive parts connected to PEN • System Characteristics : – Low earth fault loop impedance – High earth fault current – More than one earth fault loops • Advantages : no earth wire required; allow of multi-point earth, better earthing continuity; neutral never have float voltage; impedance of earth fault loop could be predicted • Disadvantages : If not multi-point earthed, and the neutral earth broken, the exposed metallic part may have float voltage; high earth fault level, intervenue the operation of earth fault protective device, current operated type device is not appropriated, voltage detected type could be employed Earthing System

Earthing System

TT • Supply side has one point earthing only • Exposed metal connected to consumer earth system • System characteristics : – High earth fault loop impedance – Low earth fault current – Utility company need not to provide earth for consumer • Advantages : Under earth fault condition, higher power factor; save earth wires • Disadvantages : high demand of E/F relays, individual earth system need higher investment, higher touch voltage; induce Potential gradient Earthing System

Earthing System

IT • System not connected with the earth (high impedance earth or isolated earth), all exposed conductive part connect to earth • Neutral is totally isolated • Infinity earth fault loop impedance • Deemed less chance of electric shock • Many disadvantages: phase current equal to live voltage (because of floating Neutral); no zero reference, may cause arcing when earth fault occurs; to small of earth fault level, current type earth fault detector cannot work properly Earthing System

Modern Current Earthing System • Code 12 stipulated that electric equipment used to install its own earthing protection system (TT system) and Main Earth Terminal shall connected with utility company earth point. For instance, star of transformer or metallic earth from supply cable Earthing System

Earthing System t

Earth Electrode • Design concerns: • Resistance/impedance to earth • Heat capacity (during earth fault,max 40kA) • The potential gradient around the electrode during faults • Mechanical strength and ability in anti-corrosion • Earth electrode shall be rod / pipe, tape, buried copper plate, re-bar and superstructure • More than one electrode could be connected, the electrode could be a mixed system • Long electrode generally effective than short one. However electrode too long does not have significant effects; larger size do not have great effects in earthing impedance Earthing System

Earthing System

Electric Shock Protection • Every premises shall have basic consideration to its electric equipment’s safety – Electric Shock Protection • Means of electric shock – Direct contact or indirect contact • Direct contact means direct touch to the live parts • Indirect Contact means human contact to non-conductive metal, of which the extraneous part becomes live during faults • Electric Shock Protection shall meet the requirements in Code 11B including equipotential zones and automatic disconnection under fault • IEC report 479-1(1984) had studied “The effects in inject of current into human and concerns on the current magnitude, duration and flowing path Earthing System

Earthing System

Supplementary Equipotential Bond • Supplementary equipotential bond maintain an extent of equipotential zone • Code 11F refers, all touchable non-conductive parts and connections shall be sound connected • Size of individual supplementary bond shall reference to Table11(1) in Code, min. size shall be 2.5mm2 yellow and green earth wire • Other requirements: – Min. size of bonding connecting two appliances enclosures shall not be less than the size any of the protective conductors – Min. size of bonding connecting appliances and non-conductive parts shall not be less than half size of protective conductor – Min. size of bonding between two non-conductive parts shall not be less than half size of protective conductor of appliance Earthing System

Protective Conductor • 4 type of conductor : Circuit Protective Conductor CPC, Main Equipotential Bond Conductor, Supplementary Bonding Conductor, Earthing Conductor • Protective conductor could be : individual conductor, metallic armour or sheath of cable, part of live cable, rigid metallic conduits/Trunking/Pipe duct, containment of metallic sheath • Reference to Code 11C and diagram11(1) • Size of individual protective conductor shall refer to Code Table11(1), and Table11(2), or substitue K-value to calculate equivalent area • With difference protective device, protective conductor area refer to Table11(3) to Table11(7) • Calculation of size of Equipotential conductor and supplementary bonding conductor refer to Code 11E and 11F • Size of earth conductor shall meet the requirements in Code 11H Earthing System

To sum up, with regard to safety one has to adopt a safe system of work that ensures :- Compliance with relevant legislation. All fixed and portable installations are safe and tested. All electrical appliances and cables are tested and maintained. Only safe equipment is used. This system applies to all places of work. There are no short cuts to safety Legislation and Code of practice place absolute duties on employers, employees and the self-employed to comply with all matters regarding electrical safety that are within their control. PREREQUISITES FOR SAFETY

To sum up, with regard to safety one has to adopt a safe system of work that ensures :-

Compliance with relevant legislation.

All fixed and portable installations are safe and tested.

All electrical appliances and cables are tested and maintained.

Only safe equipment is used.

This system applies to all places of work.

There are no short cuts to safety

Legislation and Code of practice place absolute duties on employers, employees and the self-employed to comply with all matters regarding electrical safety that are within their control.

• Metal pipe in specific to a diameter ( GI/CI). • Prone to swift corrosion due to straight contact with the soil. • Decompose of metal components and grounding plate. • Insufficient and inadequate Galvanization standard. Variation in Ohmic value, which may impact and trim down equipments life hence gigantic recurring maintenance costs and potential threat to the safety of human life. • Conventional and traditional method of earthing necessitates frequent maintenance and has a diminutive life, this may be required to transform in every 3-4years. • The most commonly used substances are Sodium Chloride (also known as common salt), Calcium Chloride, Sodium Carbonate, Copper Sulphate, Soft Coke and Charcoal get washed away over a period of time and salt is known to be a corrosive electrolyte, this may decay the pipe and conductor used for earthing hence may not present consistent ohmic value. • Much cumbersome and protracted process to install and have a need of very deep holes in the earth any where between 40-100 feet. Circulation of short circuit current is comparatively fewer in terms of charge dissipation hence produces soaring potential at the pit resulting in low fault current as measure up to preferred tripping circuit of fault protection relays. Conventional Earthing (PIT) Type

IT employs highly secured strip in pipe in various sizes as per grounding requirements instead solitary GI /CI pipe. • Earthing Electrode does not at all get nearer in direct contact with the soil. • Sealed maintenance free chemical filled Electrodes installed with high quality particular & specific unsolvable chemical compounds prevent and protect against any decompose. • Compliant to IS: 3043 1987 code of practice for earthing . Electrode and conductors are adequately galvanized (80-100 microns) and deliver steady & consistent Ohmic value. • Ultramodern techniques and compliant to earthing standard along with reliable chemical filled maintenance free AlfredKim electrodes / GBFC (grounding back fill compound) lasts longer with no recurring maintenance and hassles. • GBFC is a permanent & maintenance free (No recharging with salt or chemical which may be corrosive) and maintain earth resistivity with time. These compounds sets firmly and not dissolves or decompose or otherwise pollute the soil. Compound Earthing - Electrode

Compact unit, make a hole in the ground by 6” to 8” in diameter to the desired depth of the size of an Earthing Electrode (2/3 meters), trouble-free and painless process to install, occupies lesser leg room and can be mounted in less than an hour. • Earthing Electrode is bound with exceedingly conductive soil to ensure the dissipation of charge from the electrode is extremely high and the current mass/ solidity across the electrode is exceptionally low resulting into soaring fault current that is sufficient and adequate enough to trip the fault relays. Compound Earthing - Electrode

In the last three decades the transmission and distribution of electricity has been taken over by extensive use of Alluminium conductors and cables. It is a delibrate decision of Government of India To conserve the scarce resources of copper. It is the modern practice today to opt for chemical/compound electrode earthing Which is more efficient and long lasting and easy to install. USED OF GALVANISED - IRON

The overall requirements to ensure safety are : 1. Any installation, use and maintenance of equipment must reflect specific safety requirements with regard to adverse conditions i.e. weather conditions, exposure to corrosive or flammable environments, operation in adjusty atmosphere etc. 2. Recommended clearances and creepage distances in accordance with the system voltage should be maintained. 3. Connections should always be suitable and adequate for the purpose for which they are being used. The use of electrical tape alone for connections is forbidden. 4. It must be ensured that any protection for electrical installations and equipment e.g. fuses and earth leakage circuit breakers (ELCBs), are suitably rated, sufficient and within safe working limits. In the case of ECLBs the test trip button should be operated regularly to check its healthiness. 5. Protective devices for under voltage, over current, short circuit, earth fault etc. should be incorporated in accordance with regulations and recommended codes of practice. CONCLUSIONS AND RECOMMENDATIONS

6. Portable electrical tools should either be all insulated or of double insulation construction where possible. Where portable equipment with earthed metalwork is used, it is recommended that portable or fixed earth leakage protection be used. This is particularly important in harsh environments. 7. All electrical installations and equipment must have adequate means to enable them to be isolated from the electric supply in order to prevent danger. 8. All isolator switches should be easily accessible and passageways to them kept clear at all times. 9. All switches and fuse ways must be clearly labeled as to indicate the circuit or function controlled and all switches and distribution covers must be kept closed at all times unless being worked on by a competent authorized person. 10. Whereever possible, suitable interlocks should be provided to ensure correct switching sequence and fail-safe disconnection. 11. Adequate working space i.e. access and lighting must be provided to all electrical equipment on which or near which work is being carried out which may give rise to danger. CONCLUSIONS AND RECOMMENDATIONS

12. There should be adequate arrangements to ensure that electrical equipment that has been made ‘dead’, whilst work is being carried out on or near such equipment, cannot be electrically charged if this would then present danger. This can be physically achieved by ensuring that a ‘lock-out’ system is used, i.e. the isolator controlling equipment is physically locked in the ‘off’ position. Where a ‘lock-out’ system cannot be used then there should be a procedure for ensuring that fuses are removed and held by the authorized person carrying out the work. Any work being undertaken on an electrical installation or equipment should be subject to a safe system of work and the Permit-to-Work Procedure. 13. Where work on electrical equipment is being undertaken by ‘in-house’ competent persons then suitable protective equipment must be provided. Examples of such equipment may be goggles, gloves, insulating mats, insulated tools and test probes. CONCLUSIONS AND RECOMMENDATIONS

14. Notices giving details of emergency resuscitation procedures in the event of electrick shock should be displayed at those locations where the risk of electric shock is greater e.g. sub-stations and electrical test areas. 15. Only competent authorized persons, i.e. those with sufficient experience and training, should be engaged in any work on an electrical installation or equipment. CONCLUSIONS AND RECOMMENDATIONS