He will swap jobs with Pol Lt Gen Suthep Detraksa, commander of the Provincial Police Region 5.
The EC decided on Wednesday that as a caretaker, the government has limited powers under Section 181 of the charter and government official transfers could be done only when it is necessary, the source said.
It noted that the transfer was made outside the annual reshuffling seasons.
Besides, Pol Lt Gen Khamronwit has only four months remaining before retirement.
Some commissioners also raised the possibility that Police Division 5, which covers the North, is a stronghold of a political party.
It therefore asked the police chief to explain the reasons for the transfer on May 20.
Pol Lt Gen Khamronwit, a staunch supporter of Thaksin Shinawatra, is a target of strong criticism by the People's Democratic Reform Committee for throwing full support behind former prime minister Yingluck Shinawatra.
The reshuffling of police officers is the prerogative of the Police Commission.
The decisions of a caretaker cabinet have to be approved by the EC to prevent the ruling parties from using state resources to their advantage ahead of the election.