A. 100-300 meters
B. 40-50 meters
C. 50-80 meters
D. 80-100 meters
Answer: B. 40-50 meters
Explanation:
Indian electricity rules:
All-electric supply lines and apparatus shall be sufficient in power and size of sufficient mechanical strength for the work they may be required to do, and, so far as is shall be constructed, installed, protected, worked, and maintained under the standards of the Indian Standards Institution to prevent danger.
For carrying the overhead line, wooden poles, concrete poles, steel poles, and rail electric poles are used.
Which poles are to be used, depends on the importance of load, location, and place, the cost-effectiveness of such construction, including maintenance cost, keeping its profit element in mind.
Wooden poles:
In the earlier period, wooden poles are used for 400 volts and 230 volts L.T. line and II.K.V.H.T. line in a massive way.
In some casess wooden poles are used for33 kV line.
The cost-effectiveness of a wooden pole is much less in comparison to other electric poles and the expenditure incurred for its foundation is also comparatively very less.
If proper maintenance and treatment are done on the wood, the wooden pole is lost for a long period.
The recommended span in the case of wooden poles is 40 – 50 meters.
The breakdown force is between 450 kg / cm2 and / above 850 kg / cm2.
As per the Indian Electricity rule in overhead systems, the recommended span of various support poles is given below
| Line-support | Recommended span |
| Wooden pole | 40-50 meters |
| RCC pole | 80 - 100 meters |
| Steel pole | 50 to 80 meters |
| Steel tower | 300 meters or above |
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