Ranjan took charge of the country's largest paramilitary force after incumbent Pranay Sahay retired from service and the government did not announce a new Director General for the force.
He is expected to visit the Central Reserve Police Force (CRPF) headquarters tomorrow for formal interaction with officers.
The Union Home Ministry is expected to announce a new chief for the three lakh personnel strong force soon as a panel of senior IPS officers has already been prepared and sent to the Appointment Committee of Cabinet headed by Prime Minister Manmohan Singh for approval, official sources said.