Megger dcm310320 current clamp meters megger 1000 303 the megger dcm310 digital clamp meter is ideal for use during the installation maintenance and checking of electrical systems and equipment it measures ac current up to 400a with a maximum conductor size of 27mm it also has a max hold feature to automatically store and display the maximum value measured over a period of time supplied with a battery pouch and user guide megger 1000 303 dcm310 current clamp meter