IS 9537:1983 Part 3 is the Indian Standard (BIS) for conduits for electrical installations - part 3: rigid steel conduits. This standard specifies the material, dimensional, constructional, and mechanical requirements for rigid steel conduits intended for the protection of electrical wiring. It covers two classes of conduits (Class A and Class B) and various levels of corrosion protection, ensuring safety and durability in electrical installations.
Specifies requirements for rigid steel conduits used for the protection of electrical wiring installations.
Overview
- Status
- Current
- Usage level
- Frequently Used
- Domain
- MEP — Electrical Installations
- Type
- Specification
- Amendments
- Amendment 1 (August 1986); Amendment 2 (December 1993)
Also on InfraLens for IS 9537
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! Always use a proper pipe bender to avoid kinking the conduit, which compromises its integrity and makes wire pulling difficult.
! For outdoor or corrosive environments, specify conduits with Class 4 (Heavy) zinc coating for long-term rust prevention.
! Ensure threads are cleanly cut and burrs are removed to maintain good electrical continuity for earthing through the conduit system.
Frequently referenced clauses
Updates & Amendments2 amendments
Amendment 1 (August 1986)
Amendment 2 (December 1993)
Consolidated list per BIS. For the text of each amendment, refer to the BIS portal link above.
steelgalvanized steelconduit
International Equivalents
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International Comparison — Coming Soon
We're adding equivalent international standards for this code.
Key Values6
Quick Reference Values
Standard supplied length3.0 m (±10 mm)
External diameter of 25mm conduit25.0 mm (+0, -0.3 mm)
Minimum wall thickness for 25mm Class B conduit1.40 mm
Thread type for screwable conduitsMetric screw threads as per IS 1367 series
Minimum compression force resistance (Heavy Duty)1250 N over 200 mm
Minimum impact resistance at -5°C (Heavy Duty)2 kg from 100 mm height
Tables & Referenced Sections
Key Tables
Table 1: Dimensions of Rigid Steel Conduits
Table 2: Test Requirements for Mechanical Properties
Key Clauses
Clause 6: Dimensions
Clause 7: Construction
Clause 8: Mechanical Properties
Clause 10: Marking
Clause 11: Tests
Frequently Asked Questions4
What are the common nominal sizes for rigid steel conduits?+
Common sizes include 16, 20, 25, 32, 40, 50, and 63 mm (Table 1).
What is the difference between Class A and Class B conduits?+
Class B conduits have a thicker wall than Class A for the same nominal size, providing greater mechanical strength and protection (Table 1).
What is the standard length of a steel conduit?+
The standard length is 3 metres with a tolerance of ±10 mm. Other lengths can be supplied by agreement (Clause 6.3).
How are conduits marked?+
Conduits are marked with the manufacturer's name/trademark and may be color-coded for classification (e.g., Heavy Protection). The BIS certification mark may also be present (Clause 10).
QA/QC Inspection Templates
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QA/QC templates coming soon for this code.