While conducting a pull test for the coiled tubing connector . The pull test plate was rigged up and the dimple clamp was applied to be pull tested at 30,000lbs against the injector head riser above the CTU BOP stack. While conducting the pull test, the CTU operator pulled to approximately 24,000lbs, when the pull test plate clamp disengaged and the test plate dropped to the rig floor with the connector.