What causes water to drip from the AC duct work in basements?
The is quite simple, your duct work is not insulated somewhere. What is happening is the really cold air is blowing through the duct work and where it is not insulated, its causing condensation to form. It then builds up and starts dripping. You can either go to a hardware store and ask them for duct wrap or just buy a roll of fiberglass insulation and wrap it around and secure with duct tape.