Circuit breaker limits are dynamic, they change with time!!! Dont know the exact mechanism but the levels are different if Circuit is hit before 1 PM or after 1 PM...etc. etc.
When is trading halted
Trading will be halted if index drops 15 per cent.
According to data on the BSE website, "In case of a 10 per cent movement of either index, there would be a 1-hour market halt if the movement takes place before 1:00 p.m.
In case the movement takes place at or after 1 p.m. but before 2:30 p.m. there will be a trading halt for half an hour. In case the movement takes place at or after 2:30 p.m. there will be no trading halt at the 10 per cent level and the market will continue trading.
"In case of a 15 per cent movement of either index, there will be a 2-hour market halt if the movement takes place before 1:00 p.m. If the 15 per cent trigger is reached on or after 1:00 p.m. but before 2 p.m., there will be 1-hour halt. If the 15 per cent trigger is reached on or after 2:00 p.m. the trading will halt for the remainder of the day.
"In case of a 20 per cent movement of the either index, the trading will be halted for the rest of the day."
(rediff.com)
regards
rkpahwa