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IS 12559:1988 is the Indian Standard (BIS) for selection, installation and maintenance of electrical equipment for building construction sites. This code provides guidelines for the selection, installation, and maintenance of temporary electrical systems on building construction sites. It emphasizes personnel safety from electrical hazards, covering supply systems, circuit protection, equipment installation, earthing, inspection, and maintenance procedures.
Provides recommendations for safety related to electrical installations, selection, installation, and maintenance of electrical equipment on construction sites.
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
Direct international equivalent covering temporary electrical installations on construction and demolition sites.
Requirements for Electrical Installations, IET Wiring Regulations (Section 704: Construction and demolition site installations)
The UK's national wiring code, with a specific section that aligns very closely with the scope of IS 12559.
AS/NZS 3012:2019Standards Australia / Standards New Zealand, Australia/New Zealand
HighCurrent
Electrical installations - Construction and demolition sites
A dedicated standard for construction sites, covering similar principles of temporary power, distribution, and safety.
NFPA 70:2023 (Article 590)National Fire Protection Association (NFPA), USA
MediumCurrent
National Electrical Code (NEC) (Article 590: Temporary Installations)
Covers temporary electrical installations, but with different voltage standards, terminology, and system philosophies.
Key Differences
≠IS 12559:1988 is advisory on the use of Residual Current Devices (RCDs/RCCBs), recommending them 'wherever practicable'. Modern standards like IEC 60364-7-704 mandate 30 mA RCD protection for almost all final circuits and socket outlets.
≠While IS 12559 recommends reduced voltage systems (e.g., 110V) for safety, UK practice (BS 7671) is far more prescriptive, strongly favoring a 110V centre-tapped-to-earth (CTE) system, providing a maximum of 55V to earth under fault conditions.
≠Modern international standards specify stringent periodic inspection and testing regimes (e.g., 3-monthly tests for portable equipment under AS/NZS 3012). IS 12559 only calls for 'regular inspection' without defining specific intervals or tests.
≠IEC 60364-7-704 and BS 7671 mandate minimum ingress protection ratings for enclosures (e.g., IP44 for distribution assemblies), whereas IS 12559 uses general terms like 'robustly constructed' and 'weatherproof' without specifying IP codes.
Key Similarities
≈All standards emphasize the fundamental requirement of protecting persons from electric shock through measures like earthing, bonding, and automatic disconnection of supply.
≈There is a common principle across all standards that temporary wiring and cables must be adequately protected from mechanical damage, either by their construction (e.g., armoured) or by their installation method (e.g., routing, containment).
≈All the compared standards require the provision of clearly marked and readily accessible means for emergency switching of the installation or parts thereof.
≈A core similarity is the mandatory use of a separate protective conductor (earth wire) run to all equipment and distribution points to ensure an effective fault path, aligning with the TN-S system recommended by IS 12559.
Parameter Comparison
Parameter
IS Value
International
Source
Shock Protection for Socket Outlets
Use of Earth Leakage Circuit Breakers (RCCB) is recommended 'wherever practicable'. No trip rating is mandated.
Mandatory protection by a 30 mA RCD for all socket-outlets with rated current up to 32 A.
IEC 60364-7-704:2017
Reduced Voltage System for Hand Tools
Use of a reduced voltage system (e.g. 110 V or 24 V) is recommended for safety.
Use of a 110 V centre-tapped to earth (55 V to earth) system is the preferred method for portable tools.
BS 7671 (Section 704)
Minimum Protection for Distribution Boards
Enclosures shall be 'robustly constructed' and 'weather-proof'.
Assemblies for distribution (ASs) shall have a degree of protection of at least IP44.
IEC 60364-7-704:2017
Periodic Inspection Interval
A system of 'regular inspection and maintenance' shall be carried out. (Frequency not specified).
Transportable equipment must be inspected and tested at least every 6 months. Hand-held equipment every 3 months.
AS/NZS 3012:2019
Separation of Neutral & Protective Conductor
Recommends a 5-wire system from the source, implying separate Neutral and Protective conductors (TN-S).
On the construction site, the protective conductor and the neutral conductor shall be separate (TN-S system).
IEC 60364-7-704:2017
Minimum Conductor Size (Flexible Cords)
For portable and transportable apparatus, not less than 1.5 mm² copper.
Flexible cables for general use shall have a minimum cross-sectional area of 1.5 mm² copper.
BS 7671 (Section 704)
⚠ Verify details from original standards before use
Key Values6
Quick Reference Values
Maximum voltage for portable hand lamps24 V
Maximum voltage for portable tools240 V (with ELCB/RCCB protection)
Recommended sensitivity for ELCB/RCCB30 mA
Minimum clearance of lowest conductor (overhead line) from ground across a street5.8 m
Minimum clearance of lowest conductor (overhead line) along a street5.5 m
Minimum depth for underground cables (direct buried)0.6 m
Tables & Referenced Sections
Key Tables
Table 1 - Recommended Minimum Clearances for Overhead Lines
What is the maximum permissible voltage for a portable hand lamp on a construction site?+
24V, to ensure safety in potentially damp, confined, or rough environments (Clause 7.4.2.2).
Are Earth Leakage Circuit Breakers (ELCBs/RCCBs) required for temporary installations?+
Yes, their use is strongly recommended for all socket outlets to provide protection against direct and indirect contact shocks (Clause 6.3).
How should electrical cables be run across a site?+
Cables should be run overhead with adequate clearance or be buried/placed in protected channels to prevent mechanical damage from site traffic and activities (Clause 7.1).
What is the minimum clearance for an overhead power line on a construction site?+
For lines crossing a street, the minimum clearance is 5.8 meters from the ground to the lowest conductor (Table 1).