It is the homeowner's responsibility to be sure their contractors have permits. The Connecticut State Statutes have penalties for violations including fines up to $1,000 and possible imprisonment. Homeowners can find information on contractor registration and licensing here.
According to the 2015 International Residential code portion of the Connecticut State Building Code, section R109.3: It shall be the duty of the permit holder or their agent to notify the building official that such work is ready for inspection.