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CEAR namely Central Electricity Authority (Measures relating to Safety and Electric Supply) Regulations, 2010 [1] are regulations framed by Central Electricity Authority of India under Indian Electricity Act, 2003, to regulate measures relating to safety and electric supply in India.
CEAR came into effect 20 September 2010, in place of The Indian Electricity Rules, 1956.
The Electricity Act, 2003, was formulated combining the Indian Electricity Act 1910 and Indian Electricity (supply) Act 1948. [2]
Under CEAR, rule 41, there is specific provision of earthing neutral wire of a 3-phase, 4-wire system and the additional third wire of a 2- phase, 3-wire system. Earthing is to be done with two separate connections. Grounding system also to have minimum two or more earth pits (electrode) such that proper grounding takes place. As per the rule 42, installation with load above 5 kW exceeding 250 V shall have suitable Earth leakage protective device to isolate the load in case of earth fault or leakage. [3]
Neutral and earth run separately on overhead line/cables. Separate conductor for overhead lines and armouring of cables are used for earth connection. Additional earth electrodes/pits are installed at user ends for proper earth.
All metal casing or metallic coverings of electric supply line or apparatus to be connected with earth and all such earthling points shall be so joined to make good mechanical and electrical connection in complete system.
Earthing in an underground mine shall be carried out by connection to an earthing system at the surface of the mine as per rule 99.
As per rule 100, protective equipment is to be placed in the mines for automatic disconnection of supply when there is earth fault exceeding 750 milliampere in 250 V to 1000 Volt installations. For open cast mine the limit is 50 ampere in installations of voltage exceeding 1100 V and up to 11 kV. The earth leakage current is to be restricted by placing suitable neutral grounding resistance (NGR) in all the distribution transformers.
Chapters and regulations there in: [4] -
1 Short title and Commencement
2 Definitions
3 Designating person(s) to operate and carry out the work on electrical lines and apparatus
4 Inspection of designated officers and other safety measures
5 Electrical Safety Officer
6 Safety measures for operation and maintenance of electric plants
7 Safety measures for operation and maintenance of transmission, distribution systems
8 Keeping of records and inspection there of
9 Deposit of maps
10 Deposit of printed copies
11 Plan for area of supply to be made and kept open for inspection
12 General safety requirements, pertaining to construction, installation, protection, operation and maintenance of electric supply lines apparatus
13 Service lines and apparatus on consumer’s premises
14 Switchgear on consumer’s premises
15 Identification of earthed and earthed neutral conductors and position of switches and switchgear therein
16 Earthed terminal on consumer’s premises
17 Accessibility of bare conductors
18 Danger Notices
19 Handling of electric supply lines and apparatus
20 Supply to vehicles and cranes
21 Cables for portable or transportable apparatus
22 Cables protected by bituminous materials
23 Street boxes
24 Distinction of different circuits
25 Distinction of the installations having more than one feed
26 Accidental charging
27 Provisions applicable to protective equipment
28 Display of instructions for resuscitation of persons suffering from electric shock
29 Precautions to be adopted by consumers, owners, occupiers, electrical contractors, electrical workmen and suppliers
30 Periodical inspection and-testing of Installations
31 Testing of consumer's installation
32 Installation and testing of generating units
Chapter - IV General conditions relating to supply and use of electricity
33 Precautions against leakage before connection
34 Leakage on consumer's premises
35 Supply and use of electricity
36 Provisions for supply and use of electricity in multi-storied building more than 15 meters in height
37 Conditions applicable to installations of voltage exceeding 250 Volts
38 Appeal to Electrical Inspector in regard to defects
39 Precautions against failure of supply and notice of failures
40 Test for resistance of insulation
41 Connection with earth
42 Earth leakage protective device
Chapter - VI Safety Provisions for Electrical Installations and apparatus of voltage exceeding 650 volts
43 Approval by Electrical Inspector
44 Use of electricity at voltage exceeding 650 Volts
45 Inter-locks and protection for use of electricity at voltage exceeding 650 Volts
46 Testing, Operation and Maintenance
47 Precautions to be taken against excess leakage in case of metal sheathed electric supply lines
48 Connection with earth for apparatus exceeding 650 V
49 General conditions as to transformation and control of electricity
50 Pole type sub-stations
51 Condensers
52 Supply to luminous tube sign installations of voltage exceeding 650 Volts but not exceeding 33 kV
53 Supply to electrode boilers of voltage exceeding 650 Volt but not exceeding 33 kV
54 Supply to X-ray and high frequency installations
55 Material and strength
56 Joints
57 Maximum stresses and factors of safety
58 Clearance above ground of the lowest conductor of overhead lines
59 Clearance between conductors and trolley wires
60 Clearance from buildings of lines of voltage and service lines not exceeding 650 Volts
61 Clearances from buildings of lines of voltage exceeding 650 V
62 Conductors at different voltages on same supports
63 Erection or alteration of buildings, structures, flood banks and elevation of roads
64 Transporting and storing of material near overhead lines
65 General clearances
66 Routes proximity to aerodromes
67 Maximum interval between supports
68 Conditions to apply where telecommunication lines and power lines are carried on same supports
69 Lines crossing or approaching each other and lines crossing street and road
70 Guarding
71 Service lines from overhead lines
72 Earthing
73 Safety and protective devices
74 Protection against lightning
75 Unused overhead lines
76 Laying of cables
77 Protection against electromagnetic interference
78 Application of chapter
79 Voltage of supply to vehicle
80 Insulation of lines
81 Insulation of returns
82 Proximity to metallic pipes
83 Difference of potential on return
84 Leakage on conduit system
85 Leakage on system other than conduit system
86 Passengers not to have access to electric circuit
87 Isolation of sections
88 Minimum size and strength of trolley wire
89 Height of trolley wire and length of span
90 Earthing of guard wires
91 Proximity to magnetic observatories and laboratories
92 Records
93 Application of chapter
94 Responsibility for observance
95 Notices
An electrical insulator is a material in which the electron does not flow freely or the atom of the insulator have tightly bound electrons whose internal electric charges do not flow freely; very little electric current will flow through it under the influence of an electric field. This contrasts with other materials, semiconductors and conductors, which conduct an electric current more easily. The property that distinguishes an insulator is its resistivity; insulators have higher resistivity than semiconductors or conductors. The most common examples are non-metals.
In electrical engineering, ground or earth is the reference point in an electrical circuit from which voltages are measured, a common return path for electric current, or a direct physical connection to the earth.
Electric power distribution is the final stage in the delivery of electric power; it carries electricity from the transmission system to individual consumers. Distribution substations connect to the transmission system and lower the transmission voltage to medium voltage ranging between 2 kV and 35 kV with the use of transformers. Primary distribution lines carry this medium voltage power to distribution transformers located near the customer's premises. Distribution transformers again lower the voltage to the utilization voltage used by lighting, industrial equipment and household appliances. Often several customers are supplied from one transformer through secondary distribution lines. Commercial and residential customers are connected to the secondary distribution lines through service drops. Customers demanding a much larger amount of power may be connected directly to the primary distribution level or the subtransmission level.
A residual-current device (RCD), or residual-current circuit breaker (RCCB), is a device that quickly breaks an electrical circuit to prevent serious harm from an ongoing electric shock. Injury may still occur in some cases, for example if a human falls after receiving a shock, or if the person touches both conductors at the same time.
An Earth-leakage circuit breaker (ELCB) is a safety device used in electrical installations with high Earth impedance to prevent shock. It detects small stray voltages on the metal enclosures of electrical equipment, and interrupts the circuit if a dangerous voltage is detected. Once widely used, more recent installations instead use residual-current devices which instead detect leakage current directly.
The National Electrical Code (NEC), or NFPA 70, is a regionally adoptable standard for the safe installation of electrical wiring and equipment in the United States. It is part of the National Fire Code series published by the National Fire Protection Association (NFPA), a private trade association. Despite the use of the term "national", it is not a federal law. It is typically adopted by states and municipalities in an effort to standardize their enforcement of safe electrical practices. In some cases, the NEC is amended, altered and may even be rejected in lieu of regional regulations as voted on by local governing bodies.
In the electrical appliance manufacturing industry, the following IEC protection classes are defined in IEC 61140 and used to differentiate between the protective-earth connection requirements of devices.
As the neutral point of an electrical supply system is often connected to earth ground, ground and neutral are closely related. Under certain conditions, a conductor used to connect to a system neutral is also used for grounding (earthing) of equipment and structures. Current carried on a grounding conductor can result in objectionable or dangerous voltages appearing on equipment enclosures, so the installation of grounding conductors and neutral conductors is carefully defined in electrical regulations. Where a neutral conductor is used also to connect equipment enclosures to earth, care must be taken that the neutral conductor never rises to a high voltage with respect to local ground.
Electrical wiring is an electrical installation of cabling and associated devices such as switches, distribution boards, sockets, and light fittings in a structure.
Electrical wiring in the United Kingdom is commonly understood to be an electrical installation for operation by end users within domestic, commercial, industrial, and other buildings, and also in special installations and locations, such as marinas or caravan parks. It does not normally cover the transmission or distribution of electricity to them.
High voltage electricity refers to electric potential large enough to cause injury or damage. In certain industries, high voltage refers to voltage above a certain threshold. Equipment and conductors that carry high voltage warrant special safety requirements and procedures.
An overhead power line is a structure used in electric power transmission and distribution to transmit electrical energy across large distances. It consists of one or more uninsulated electrical cables suspended by towers or poles.
A traction network or traction power network is an electricity grid for the supply of electrified rail networks. The installation of a separate traction network generally is done only if the railway in question uses alternating current (AC) with a frequency lower than that of the national grid, such as in Germany, Austria and Switzerland.
An earthing system or grounding system (US) connects specific parts of an electric power system with the ground, typically the Earth's conductive surface, for safety and functional purposes. The choice of earthing system can affect the safety and electromagnetic compatibility of the installation. Regulations for earthing systems vary considerably among countries, though most follow the recommendations of the International Electrotechnical Commission. Regulations may identify special cases for earthing in mines, in patient care areas, or in hazardous areas of industrial plants.
Extra-low voltage (ELV) is an electricity supply voltage in a range which carries a low risk of dangerous electrical shock. There are various standards that define extra-low voltage. The International Electrotechnical Commission member organizations and the UK IET define an ELV device or circuit as one in which the electrical potential between conductor or electrical conductor and earth (ground) does not exceed 50 V a.c. or 120 V d.c..
In electrical engineering, earth potential rise (EPR) also called ground potential rise (GPR) occurs when a large current flows to earth through an earth grid impedance. The potential relative to a distant point on the Earth is highest at the point where current enters the ground, and declines with distance from the source. Ground potential rise is a concern in the design of electrical substations because the high potential may be a hazard to people or equipment.
Portable appliance testing is the name of a process in the United Kingdom, the Republic of Ireland, New Zealand and Australia by which electrical appliances are routinely checked for safety. The formal term for the process is "in-service inspection & testing of electrical equipment". Testing involves a visual inspection of the equipment and any flexible cables for good condition, and also where required, verification of earthing (grounding) continuity, and a test of the soundness of insulation between the current carrying parts, and any exposed metal that may be touched. The formal limits for pass/fail of these electrical tests vary somewhat depending on the category of equipment being tested.
Stray voltage is the occurrence of electrical potential between two objects that ideally should not have any voltage difference between them. Small voltages often exist between two grounded objects in separate locations, due to normal current flow in the power system. Large voltages can appear on the enclosures of electrical equipment due to a fault in the electrical power system, such as a failure of insulation.
Electrical safety testing is essential to ensure safe operating standards for any product or establishment that uses electricity. Various governments and agencies have developed stringent requirements for electrical products that are sold world-wide. In most markets it is mandatory for a product to conform to safety standards promulgated by safety and standard agencies such as UL, VDE, CSA, BSI and so on. To conform to such standards, the product must pass safety tests such as the high voltage test, Insulation Resistance Test, Ground (Earth) Bond and Ground Continuity Test and Leakage Current Test. These tests are described in IEC 60335, IEC 61010 and many other national and international standards.