1. Connection between FG and -V

Connecting the FG terminal to the output −V terminal does not cause any operational issues for the power supply. However, doing so will result in failing to meet the withstand voltage specifications between the secondary side and FG, as well as between the primary and secondary sides. In addition, this connection reduces the insulation between the primary and secondary sides to basic insulation only, which does not comply with safety standards.

2. Adverse Effects of Eliminating the Secondary Grounding Capacitor

In general, removing the secondary-side grounding capacitor may cause the secondary potential (output voltage) to become unstable and may increase the level of output common-mode noise. If you use a product in which the secondary grounding capacitor has been removed, please ensure that sufficient evaluation is conducted beforehand.