IRC 32:1969 is the Indian Standard (IRC) for standards for vertical and horizontal clearances of overhead electric power and telecommunication lines as related to roads. IRC 32:1969 is the Indian standard for clearance between roads and overhead electric power / telecom lines. It addresses a perennial and often-overlooked infrastructure coordination problem — where road centre-line and power line routes intersect. The Indian electrical grid's 11 kV through 765 kV transmission corridors cross thousands of roads annually. Each crossing must satisfy vertical clearance (typically 7.5 m for 33 kV, 13 m for 220 kV, 17 m for 765 kV) and horizontal setback (2.5-8.5 m depending on voltage). Road authorities verify against IRC 32 during DPR stage; utility companies are bound to maintain clearances during conductor sag or re-sag. The code is old (1969) but actively cited in every road project NIT; updating work has been ongoing since 2015 but no new edition yet published. Familiarity with IRC 32 prevents the frustration of road projects being delayed by utility relocation.
Specifies minimum vertical and horizontal clearances between road centreline / carriageway surface and overhead electric power lines, telecommunication wires, and other suspended services. Applies to road design, power line installation, and highway expansion projects.
- Status
- Current
- Usage level
- Frequently Used
- Domain
- Transportation — Road Design and Safety
- Type
- Standard
- Amendments
- Amendment No. 1 (2015) — clarified 765 kV clearance requirements for Indian transmission expansion
Also on InfraLens for IRC 32
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! The 5.5 m vertical clearance is a road-design baseline, but transmission lines above 11 kV require much more — always use the voltage-specific value from Table 1.
! Sag allowance — conductors droop further in summer heat (maximum sag at 75-80°C). Clearances should be verified at maximum sag, not just at stringing temperature.
! Wind-induced swing can shift conductors horizontally by 1-2 m under 40-60 m/s wind. Horizontal clearance calculation should include wind swing allowance per IS 5613.
! Road widening from 2-lane to 6-lane often violates IRC 32 clearances — existing transmission lines need either taller towers or longer conductors to compensate. Typical utility relocation cost: ₹50 lakh to ₹5 crore per km.
! Transmission line right-of-way is typically wider than IRC 32 minimum — 30 m ROW for 220 kV, 50 m for 400 kV, 65 m for 765 kV — to ensure clearances under all conditions.
! State electricity boards and transmission companies (PGCIL, state transmission utilities) have internal standards often stricter than IRC 32 — verify before design freeze.
! Pedestrian overbridges near transmission lines — the added height from bridge deck makes clearance critical. Many urban overbridges near substations have had clearance issues; design carefully.
! Ground-level LT lines (low-tension, 230/400 V) at road crossings commonly use wood poles at 7-8 m height. When widening roads, verify still above 5.5 m clearance.
! Underground cables are preferred in dense urban areas partly to avoid IRC 32 complications — but underground cost is 5-10× overhead at transmission voltages.
! Overhead signs, gantries, cantilever signal arms — these also require clearance from adjacent utility lines; often overlooked during design.
! Crane operations near roads: telescopic mobile crane boom can reach 30-50 m height. Construction of buildings near roads with overhead lines requires crane movement analysis.
! Temporary road diversions during construction — ensure diverted route doesn't reduce clearance to existing overhead lines. Many road construction accidents trace to temporary road under live lines.
! Fire risk — vegetation growth near transmission lines can grow into clearance envelope. Clearing ROW maintenance is the utility company's responsibility but road authorities should monitor.
! Railway overhead contact wire (25 kV) crossings — separate higher-stringency clearance per Railway Electrification standards.
! The IRC 32 revision since 2015 intends to add explicit provisions for wind farm and solar farm power collection lines which cross rural roads — draft still under review.
! For any new road project, the design team must map all existing and planned transmission lines in the corridor. PGCIL and state transmission utilities provide this information.
! Clearance violations found during inspection require immediate mitigation — utility company bears cost if line was pre-existing and road raised; road authority bears cost if line installed after road.
! Climate change has increased ice loading in Himalayan regions — traditional ACSR conductor ice allowance may be inadequate for 500 kV transmission lines in high-altitude Himalayan road crossings.
! Power line crossing over highway median — allowed if clearances are met; commonly used for transmission on existing road corridors.
! Telecommunication clearance (5 m vertical, 3 m horizontal) is minimum; many modern fiber optic aerial runs prefer 7-10 m vertical for reliability.