Electrical safety in construction
- 2. INTRODUCTION Electrical safety is highly important Ratio of fatalities to injuries is higher for electrical accidents compared to other categories of injury. Electricity constitutes a hidden danger which cannot be seen. Devastating accidents cause due to fire or electrocution. Hence, it should be used in construction industry with utmost care.
- 3. ELECTRICAL HAZARDS Electrical hazards are of mainly 2 types. 1. Persons or livestock accidentally or due to negligence come in contact with live parts of an installation and get shocks or electrocuted. 2. Heat is generated due to loose contacts, improper installation, or improper use of electrical equipment resulting in breaking of fire. Preventive measures against such hazards lie in proper design of electrical installation.
- 4. ELECTRIC FACILITIES - DESIGN Electric facilities design must provide 1. Protection against both direct and indirect contact. 2. Protection against thermal effects in normal service. 3. Protection against both over currents or under currents. 4. Protection against over voltage. Protection can be effected by means of proper insulation, proper clearances, effective earthing, sensitive relaying and judicious operation and maintenance.
- 5. REGULATIONS AND STANDARDS All cabling and installation must comply with statutory rules and regulations. Some of the statutory standards which cover the rules and regulations related to electrical safety are: Indian electricity act, 1910 Electricity (supply) act, 1948 Indian Electricity Rules, 1956 National Electric Code, 1985 Other relevant rules of generating and supply authorities.
- 6. NATIONAL ELECTRICAL CODE BIS formulated NEC. It provides procedure and guidelines for selection of equipment to meet certain requirements. According to Indian Electricity rules, all installation work should be carried out in accordance with the National Electrical Code and various codes of practices issued by the BIS. The rules establish safety in a organization.
- 7. TEN COMMANDMENTS Confederation of Indian Industry has formulated 10 commandments for electrical safety. 1. Study the network carefully, and formulate the electric safety plan. 2. Check that your diagram book is up-to-date. 3. Do not assume any thing related to the things related to network or safety. 4. Before carrying out any work, check with the control room for any last minute alteration. 5. Remember, live and dead bars look exactly alike.
- 8. TEN COMMANDMENTS 6. Do not touch a conductor line unless it is earthed. 7. Do not earth a conductor unless it is proved to be dead by live line detector or any other suitable gadgets. 8. Have your own check points. 9. Plug all your feedback points; while working on bus keep it shortened and earthed with shorting clips. 10. Check and recheck any activity related to electricity.
- 9. SAFETY GUIDELINES Temporary electrical cables should be protected from damage by effectively covering. Reinforcing steel bars or metallic parts of structure should not be used for supporting electrical wires and cables, earthing etc. Buried cables should be protected and de-energized before taking up any excavation activity. Power supply cables other than illumination should be switched off beyond the working hours. While working near circuits, safe distance should be maintained. Before taking up any maintenance works, circuits should be de-energized.
- 10. Protection against direct and indirect contact with electricity should be provided by suitable means such as: Enclosure Insulation Extra low voltage where ever possible Safety isolation Earthing of neutral Earthing of normally dead parts Insulation control devices Isolated neutral
- 11. Employees working on electrical installation/equipment should be trained in fire fighting, first aid and rescue techniques. IS:1416 – safety transformers IS: 5216 – recommendation on safety procedures and practices in electrical work. Part I – General Part II – life saving techniques SP 31 – Treatment for electric shock All above are safety related codes issued by BIS.