The deceased were identified as Josna Begum, 35, wife of Alim Morol, and their son Al Amin, 18.
Mohammad Abu Sayeed, officer-in-charge of Keshabpur Police Station, said Al Amin went to a water body in the village to repair a motor for pumping water.
As he was not returning home, his mother went to the Pashim beel and found her son lying beside the motor.
When she touched him, she also got electrocuted and died on the spot.
On information, police visited the spot.