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IS 7293:1974 is the Indian Standard (BIS) for electrical safety in construction. This code of practice outlines the safety requirements for temporary electrical installations on construction and building sites. It covers aspects like temporary wiring, earthing, protection devices, and the use of portable electrical equipment to prevent electric shock and fire hazards. Note: This standard has been withdrawn.
Lays down safety requirements for electrical installations, equipment, and practices to prevent electrical hazards in construction.
! This standard is withdrawn. For current practice, refer to the National Building Code of India (NBC), particularly Part 8, Section 2, and the Central Electricity Authority (CEA) (Measures relating to Safety and Electric Supply) Regulations.
! The core principles, such as mandatory use of Earth Leakage Circuit Breakers (ELCBs) or Residual Current Circuit Breakers (RCCBs) for all temporary power outlets, remain critically important.
! Ensure all power tools are either double-insulated (Class II) or properly earthed (Class I), and that all extension cords are heavy-duty and inspected regularly for damage.
IEC 60364-7-704:2017International Electrotechnical Commission (IEC), International
HighCurrent
Low-voltage electrical installations - Part 7-704: Requirements for special installations or locations - Construction and demolition site installations
Directly addresses temporary electrical installations on construction sites, matching the electrical safety aspect.
OSHA 29 CFR 1926 Subpart KOccupational Safety and Health Administration (OSHA), USA
MediumCurrent
Safety and Health Regulations for Construction - Electrical
Provides mandatory U.S. federal regulations for all aspects of electrical safety during construction work.
BS 7375:2010British Standards Institution (BSI), UK
HighCurrent
Code of practice for distribution of electricity on construction and demolition sites
Provides UK-specific recommendations that largely align with IEC 60364-7-704.
ISO 20474-1:2017International Organization for Standardization (ISO), International
MediumCurrent
Earth-moving machinery — Safety — Part 1: General requirements
Covers safety of construction machinery, which is the primary scope of IS 7293, including basic electrical system safety.
Key Differences
≠IS 7293:1974 is a prescriptive code of practice, while modern standards like IEC 60364-7-704 are performance-based and emphasize formal risk assessment.
≠International standards (e.g., BS 7375, IEC 60364) strongly promote or mandate the use of Reduced Low Voltage (RLV) systems, such as 110V centre-tapped to earth (CTE), for portable tools. IS 7293 focuses on standard 230V with earthing and does not have a similar emphasis on RLV.
≠The requirement for Residual Current Device (RCD) / Ground Fault Circuit Interrupter (GFCI) protection is far more stringent and widespread in modern international codes than in the 1974 Indian Standard, which gives more general guidance on earth leakage protection.
≠IS 7293 combines safety for construction machinery (mechanical) with general electrical safety. Modern international practice separates these concerns into distinct standard families (e.g., ISO for machinery, IEC for electrical installations).
Key Similarities
≈All standards mandate the fundamental principle of grounding/earthing for all equipment and metallic structures to provide a safe path for fault currents.
≈The core concept of protection against direct contact with live parts through methods like insulation, barriers, and enclosures is a common requirement across all codes.
≈Both IS 7293 and its international counterparts universally require that electrical work, including installation and maintenance, be carried out only by competent, qualified, and authorized personnel.
≈The principle of isolating equipment from power sources and implementing lockout/tagout procedures before commencing maintenance or repair is a key safety measure shared by all standards.
≈Regular inspection and maintenance of electrical installations and portable equipment are stipulated in both the Indian standard and international equivalents to ensure ongoing safety.
Parameter Comparison
Parameter
IS Value
International
Source
Protection for socket-outlets (up to 32A)
Recommends use of Earth Leakage Circuit Breakers (ELCBs) where applicable.
Mandatory use of a Residual Current Device (RCD) with a sensitivity ≤ 30 mA.
IEC 60364-7-704:2017
Recommended voltage for portable hand tools
Permits 230V tools with proper earthing and ELCB protection.
Strongly recommends or requires a reduced voltage system (e.g., 110V CTE) or Safety Extra-Low Voltage (SELV).
BS 7375:2010
Minimum Ingress Protection (IP) for site distribution boards
Specifies equipment should be 'weather-proof' without defining a specific IP rating.
Requires a minimum of IP44 for assemblies for construction sites (ACS).
IEC 60364-7-704:2017
Voltage for temporary lighting
Recommends a reduced voltage of not more than 110V for temporary lighting.
Requires protection by SELV or by electrical separation for lighting circuits, unless placed out of arm's reach.
IEC 60364-7-704:2017
Testing of portable appliances
Advises 'regular' inspection and testing, without specifying intervals.
Requires a documented program of regular inspection and testing (e.g., Assured Equipment Grounding Conductor Program).
OSHA 29 CFR 1926.404(b)(1)(iii)
Emergency Switching
Requires provision of main switches for shutting off power to installations.
Each distribution assembly on site must have a device for emergency switching that is readily accessible.
IEC 60364-7-704:2017
⚠ Verify details from original standards before use
Key Values4
Quick Reference Values
Maximum voltage for portable hand lamps in confined/damp locations24 V
Minimum insulation resistance between conductors1 MΩ
Minimum insulation resistance between any conductor and earth1 MΩ
Typical voltage for temporary site distribution415 V (3-phase) or 240 V (1-phase)
No, IS 7293:1974 has been officially withdrawn by BIS. Its provisions have been superseded by the National Building Code (NBC) and CEA Safety Regulations.
What is the main safety device recommended for construction sites?+
The use of Earth Leakage Circuit Breakers (ELCBs) or Residual Current Circuit Breakers (RCCBs) for protection against electric shock is a fundamental requirement.
What does this code say about portable tools?+
It mandates that portable and transportable apparatus must be robust, properly earthed or double-insulated, and operated at reduced voltage (e.g., 110V or 24V) in hazardous locations.
What is the requirement for temporary wiring?+
Cables should be protected from mechanical damage, routed away from traffic, and should not be laid directly on the ground in wet areas. All connections must be made in suitable enclosures.