Police officials said the incident happened on Rajauli - Gaya route near Tilaiya village of the district.
The transport vehicle was carrying two brand new 'Haiwa' containers, generally used in carrying stone chips and minerals.
Sirdala Station House Officer (SHO) Ranjan Kumar said "The vehicle came in contact of a high-tension power line and the containers caught fire. The driver's helper tried to disentangle the electricity line and was electrocuted."
The police has sent the body for postmortem.