Bhavna and Vijayshri, both eight years old, were electrocuted when they stepped on a power cable covered by stagnant rain water in RR Nagar, police said.
Another girl escaped after she jumped on a cement slab. The girls were playing near their home as the schools were closed because of the rains.
Eight officials of the Electricity Board, including an Executive Engineer and an Assistant Engineer, were suspended for not ensuring the power cables did not harm people, Electricity Minister SP Velumani told reporters. He also announced Rs 2 lakh for the families of the electrocuted girls.
He said a wire from an open pillar box had touched the water, leading to the electrocution. A five-member group has been set up in the Electricity Board to ensure that such incidents do not recur, he added.
Mr Velumani said chances of electrocution were less in Chennai because of underground cabling of electric wires, but the accident took place because of the lack of proper upkeep of the pillar box. There are 40,000 such pillar boxes in the city, he added.
Angry residents protested over the deaths. They complained that negligence on the part of the authorities despite their complaints was the reason the girls died.
As rains continued to lash Chennai and suburbs, low-lying areas in Mudichur and Selaiyur near Tambaram were marooned. Varadarajapuram near Mudichur, one of the worst hit areas in the 2015 floods, was severely affected as residents started leaving for safer places.
The weather department has predicted rain or thundershowers at many places in coastal Tamil Nadu and Puducherry as well as interior Tamil Nadu for the next four days. Intermittent heavy rains have been forecast for Chennai and neighbouring Kanchipuram and Tiruvallur districts for tomorrow.
Schools in these districts were closed for the second consecutive day today, and will remain closed tomorrow also.
People complained of overflowing sewage drains in several areas. "It is saakadai (sewage) Chennai. The main sewage line is always stagnant. Whether the sewage pumping stations are working at all is a major question that has been defying an answer for a long time," said Nitya V, a resident of Mylapore in south Chennai.