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Which support for overhead transmission line has the least life
Wooden poles
Fabricated steel structure
RCC poles
Steel poles
Wooden poles
Wooden poles have the least service life among overhead transmission line supports, typically ranging from 10 to 20 years. Their longevity is limited primarily by natural decay, fungal attacks, and termite infestation, which degrade the structural integrity of the timber over time.
Wooden poles have the least service life among overhead transmission line supports, typically ranging from 10 to 20 years. Their longevity is limited primarily by natural decay, fungal attacks, and termite infestation, which degrade the structural integrity of the timber over time.
LlifeтАЛтИЭPtreatmentтАЛ тАФ where LlifeтАЛ is the operational life and PtreatmentтАЛ represents the effectiveness of chemical wood preservation.
The decay mechanism is driven by moisture absorption and exposure to environmental elements, which facilitate the growth of wood-rotting fungi. Even with chemical preservation treatments like creosoting, the porous nature of wood makes it susceptible to biological degradation when buried in soil, leading to rot at the ground-line interface.
Wooden poles are generally used for lower distribution voltages (up to 22 kV).
They are lightweight and offer excellent insulation properties, but lack the mechanical strength of steel or RCC.
Ground-line rot is the most common cause of failure for wooden supports.
Steel and RCC structures are preferred for higher voltage transmission due to longer lifespan and better durability.
Low initial installation cost
High dielectric strength (good insulation)
Lightweight and easy to transport to remote areas
Short service life (10-20 years)
High maintenance requirement
Prone to fire and termite damage
Limited mechanical strength compared to steel/RCC
Rural electrification networks
Temporary overhead power lines
Low-voltage distribution feeders
| Feature | Wooden Poles | Steel/RCC Poles |
|---|---|---|
Typical Service Life | 10-20 Years | 50+ Years |
Fabricated steel structures and RCC poles have significantly longer lives (often 50-70 years) due to their resistance to biological and environmental decay.
Option B (Fabricated steel) is chosen for long-span high-voltage lines.
Option C (RCC poles) is favored for its zero maintenance compared to steel or wood.
Option D (Steel poles) are used in urban areas where space is limited.
A is correct тАФ Wooden poles have the shortest service life due to natural biological degradation and susceptibility to environmental elements.
When comparing line supports in exams, remember: Wood = Shortest life, RCC = Longest life/Low maintenance, Steel = Best strength for long spans.