My local supply house sold me a 0-75 amp meter, and 75-5 amp donut transformer.
Check the meter carefully. Did they actually sell you a 0-75A meter, or a 0-5A meter with a 0-75A scale? You need a 5A meter for use with the CT.
Other than that, check the orientation/centering of the conductor in the CT window, and make sure all the secondary CT wiring is OK. Insert another ammeter in the CT loop, and verify how much current is being developed on the 5A side.
