JOIN USThe high-tension line was dangerously close. But oblivious to this risky proximity, Gauri Shankar stood glued to his phone on the balcony. On that night of December 14, as Shankar collapsed in shock and died in his friend’s Madiwala house, the HT line had taken another deadly, fatal turn.
Towering above the City, these HT lines are the backbone of Bengaluru’s power distribution network. But the rapid, unregulated urban sprawl has thrown to the winds the vertical and horizontal distance mandated for safety from these power lines. Result: A dramatic spike in electrocutions.
In revenue layouts across the City, multistoried structures have mushroomed within touching distance of the once distant HT lines.
Risks of accidental human contact with the wires have risen alarmingly. Does the Karnataka Power Transmission Corporation Ltd (KPTCL) now have a choice? Can BBMP hasten a course-correction to stop this unbridled expansion of risky human settlements?
KPTCL dilemma
KPTCL is caught in a dilemma. Even when its existing lines are trapped inside highly congested residential zones, it faces a dire space constraint in capacity upgrade.
“This is an enormous problem. We are unable to draw new lines to increase capacity,” says its Managing Director Jawaid Akhtar.
One option is to take the lines underground. But as Akhtar points out, the task is prohibitively expensive. “Going underground is almost 15 times costlier. However, in areas where the Right of Way is a problem, we do go underground, as in areas such as Koramangala. But we need to minimize expenditure too.”
Bangalore Electricity Supply Company (Bescom) officials feel underground is the safest option in congested inner city areas, even if it is expensive. “Existing overhead HT lines in areas such as Indiranagar and Jayanagar could be taken underground. The project could be financed through Asian Development Bank (ADB) loans,” says Bescom Director, Technical, H Nagesh.
KPTCL uses its 11 KV High Tension (HT) lines to transfer power to Bescom. This energy is then stepped down through transformers and distributed to residential and commercial outlets through a network of overhead and underground HT 440V and Low Tension 220V lines.
Safety in distance
BBMP’s building bye-laws of 2003 mandate a vertical clearance of 3.7 metres and horizontal clearance of 1.2 metres from high voltage lines upto and including 11 KV.
For high voltage lines beyond 11 KV, the horizontal clearance required is 2 metres. In the Electronic City Industrial Township Area, the rules are even more stringent. The horizontal clearance is 6 metres and vertical clearance 3.7 metres for lines with voltages ranging from 11 KV upto 33 KV.
However, building structures seldom stick to these rules, particularly, in the BBMP areas. Bescom officials blame BBMP for not enforcing the rules strictly. But Bescom personnel themselves don’t always observe the violations due to pressure of work, as Nagesh admits.
Dangerous tree-falls
Besides building violations, BBMP has another key task to prevent electrocutions: Maintenance of roadside trees. Many of these are softwood trees, which cannot withstand strong winds and fall on electric poles.
Bescom is in talks with BBMP to identify decaying trees in the City so that damage to electric wires and electrocution danger could be minimised.
Despite the high costs, Bescom had taken the underground option in areas with dense tree cover. Till March last year, the power utility had shifted 5,558 metres of HT line and 16,227 metres of LT cables underground. Over time, this could emerge as the standard, at least in the Central Business District (CBD), where several roads are now being upgraded under TenderSURE.
Simply put, the safest alternative to those overhead cables looming dangerously close to human settlements could be this: A network of dedicated underground HT and LT power ducts, laid under the pavement with cover options for regular maintenance and repair. Of course, provided someone foots the bill.