In the field of Electrical Engineering Safety, engineers and other professionals get exposed to electricity indirectly during generation, transportation, installation and usage. Such conditions might cause hazards if accurate safety measures aren't taken.
To promote the security and therefore the right usage of kit, there are certain rules and regulations formulated by the Bureau of Indian Standards (BIS). BIS follows the following five principles −
• Safety
• Ease of use and adaptability
• Simple technology
• Value for money products
• Energy efficiency and environment
BIS has published the following code for public safety standards in order to promote the right to information, transparency and accountability.
ESSENTIALS REQUIREMENTS FOR ELECTRICAL WORK
1. Personnel (both Company employees and Contractors) shall be competent to carry out electrical work and shall possess approved government authorized competency certificate for work at working voltage levels.
2. Employees/contractors working on/near electrical equipment shall be trained in emergency response/first aid.
3. Prior to carrying out any activity related to operation, maintenance or testing of electrical equipment, it shall be ensured that there is an appropriate Job Safety Analysis (JSA) supported with Hazard Identification and Risk assessment (HIRA) done and recorded.
4. Fire and explosion hazards associated with electrical equipment shall be assessed and managed.
5. Permit to Work (PTW) and Lock Out Tag Out (LOTO) Procedures to be followed.
6. All electrical work shall be done in compliance to Standard Operating Procedure (SOP)/ Standard Maintenance Procedure (SMP).
7. Checklist should be made available and filled up copies recorded.
8. Isolation and subsequent confirmation test shall be carried out to verify absence of voltage.
9. Authorized Work Area cordoning off by barricading tape/Hard barricades shall be done prior to maintenance/testing.
10. Proper illumination shall be provided if the work has to be continued during dark hours. If any hand lamp is to be used it should be of voltage level equal to or less than 24V AC
11. Hazard/flashing lights shall be installed if the work involves HV testing at 1 kV and above.
12.The room in which work is being carried out should have adequate ventilation system and emergency exit points. Adequate communication systems should be made available.
13. While working in the vicinity of live equipment the Engineer to whom PTW has been issued shall give proper information and instructions to Staff carrying out work.
14. Appropriate PPE and adequate safety apparel like arc suits shall be worn.
15. Certified and insulated tools shall be used while performing electrical work.
16. After completion of work the Removed material shall be stored / shipped to safe location.
17. After completion of work Permit Issuer shall physically check and ensure that the following are cleared before closing of PTW.
A) Grounds
B) Tools
C) Spares
D) Personnel
E) Debris
F) Scrap
18. All Electrical equipment, spares and tools should be inspected and maintained at regular intervals as per proper approved schedule.
COMPLIANCE TO WORK PROCEDURES
Persons who work near electrical equipment and are potentially exposed to electrical hazards, shall be made fully aware of the hazards and should be suitably trained on how to work safely. All the work procedures should aim at minimizing exposure to electrical hazards to an acceptable level on the basis of HIRA.
Energy isolation shall be done before carrying out work on electrical equipment as per Lock out Tag out (LOTO) procedure.
WORKING ON OR NEAR ELECTRICALLY ENERGIZED EQUIPMENT
1. Work on or near any live conductor shall be carried out only in case of exceptions, after a thorough HIRA has been carried out.
2. When working on or near energized electrical equipment it shall be ensured that no other work should be performed within the prohibited approach boundary. (Work in switchyard, multi circuit tower with other lines charged).
3. Permission to work on such locations requires authorization from a senior authorized person/Engineer in charge (as per company standard/procedure) regardless of the PPE used or design of equipment. Appropriate control measures and suitable precautions (including the provision of suitable PPE) have been taken.
4. Energized Equipment may include working on both Extra Low Voltage (ELV) systems (<50 AC or < 120 DC) and non ELV systems.
5.Testing which calls for Voltage injection is allowed within the prohibited approach boundary provided proper test equipments and PPE are used and the personnel are competent and qualified.
Recommended PPE: Helmet, voltage rated hand gloves, safety shoes, safety goggle with face shield, FR (Flame Resistant) coat, gas mask, acid resistant aprons.
General Electrical Safety Requirements Standards
- IS:900 Installation and maintenance of Induction motors
- IS:1271 Classification of insulating materials for electrical machinery
- IS:1646 Fire safety of buildings (general) electrical installation
- IS:1882 Outdoor installation of Public Address System (PAS)
- IS:1886 Installation and maintenance of Transformers
- IS:1913 General and safety requirements of electric lighting fittings
- IS:2032 Graphical symbols related to electrical technology
- IS:2274 Electrical wiring installations where system voltage is more than 658 volts
- IS:3034 Fire safety of industrial buildings (Electrical generation and distribution stations)
- IS:3072 (part-1) Installation and maintenance of switchgear where system voltage is less than 1000 volts
- IS:3106 Selection, installation and maintenance of fuse where system voltage is less than 650 volts
- IS:3638 Guide for gas operated relays
- IS:3646 Practice for interior illumination
- IS:3716 Guide for insulation coordination
- IS:3842 Guide for electrical relays for AC system
- IS:4004 Guide for lightening arrestors (non-linear ) for AC system
- IS:4146 Guide for voltage transformers
- IS:4201 Guide for current transformers
- IS:5571 Selection of electrical equipment in hazardous area
- IS:5572 Types of hazardous areas for electrical installations
- IS:5780 Intrinsically safe electrical apparatus and circuit
- IS:5908 Measurement of electrical installations in buildings
Switchgear Related Electrical Safety Standards.
- IS:375 Making and arrangement for switchgear bus-bars, main connections and auxiliary winding
- IS:694(part-1) PVC insulating cables with copper conductors (where voltage is up to 100v)
- IS:1248 Direct acting electrical indicating instruments
- IS:2147 Degrees of protections for enclosures for switchgear and control gear (low voltage)
- IS:2208 Guide for HRC fuse (up to 650v)
- IS:3202 Guide for climate proofing of electrical equipment
- IS:3231 Guide for electrical relays of power system protection
- IS:4047 Guide for heavy duty air break switches and fuses for voltage less than 1000v
- IS:4237 Requirements for switchgears and control gears for voltage up to 1000v
- IS:5987 Selection of switches where voltage is up to 1000v
- IS:335 Insulating oil for transformers and switch gear
- IS:2516(part-1,sec-2) AC circuit breakers (Tests for the voltage range 1000v to 11000v)
- IS:3427 Metal enclosed switch gear and control gear for voltage within 1000v to 11000v
- IS:722 AC electricity meters for 415 volts
- IS:1951 PVC sleeving for electrical works
- IS:2516(part-1sec-1 & part-2sec2) AC circuit breaker (Tests for voltage within 1000v)
- IS:2419 Guide for dimension of electrical indicating instruments
Motor Control Centre (MCC) related Electrical Safety Standards
- IS:1554(part-1) PVC insulated heavy duty electric cables for the voltage up to 1100v
- IS:1822 AC motor starters of voltage less than 1000v
- IS:2959 AC contactors of voltage less than 1000v
- IS:3961(part-2) Recommended current ratings for PVC insulated and PVC sheathed cables
- IS:5124 Installation and maintenance of AC induction motor starters within 1000v
- IS:2959 Guide for AC contactors of voltage less than 1000v
Transformers related Electrical Safety Standards
- IS:335 Insulating oil for transformer and switch gear
- IS:2026 Power transformers
- IS:2099 High voltage porcelain bushings
- IS:3637 Gas operated relays
- IS:3639 Fitting and accessories for power transformers
- Motors related Electrical Safety Standards
- IS:325 3-ph induction motors
- IS:4691 Degrees of protection provided by enclosures for rotating machinery
- IS:4722 Guide for rotating electrical machines
Cables related Electrical Safety Standards
- IS:1753 Aluminum conductors for insulated cables
- IS:3961(part-2) Guide for current ratings for cable
- IS:3975 Guide for mild steel wires, strips and tapes for armoring cables
- IS:5819 Guide for short circuit ratings of high voltage cables
- IS:5831 Guide for PVC insulation and sheath of electric cables
Alternators related Electrical Safety Standards
- IS:7132 Guide for testing synchronous machines
- IS:5422 Guide for turbine type generators
- IS:7306 Methods for determining synchronous machine quantities
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