The incident occurred when the bus moved to a side to give pass to another bus coming from the opposite direction near Nepura More, police officials said.
A few members of the marriage party were sitting atop the bus, and they came in contact with the 11,000 volt electric wire passing alongside the road, they said.
The bus was going from Jewri to Bhawani Bigha.
All the six passengers received electric shock and suffered serious burn injuries. They have been admitted to Nawada Sadar Hospital.