Think about what the CT stands for. Current transformer. At 500:1 you would expect 500A in the primary to produce 1A in the secondary - provided it has somewhere to go. Ammeters are usually quite low impedance so not much voltage would be developed across its terminals. As others have pointed out, the voltage depends on what is connected to the CT secondary.What is the expected voltage on the secondary side of a CT? Installed on a 480 volt circuit with CT ratio 500:1