Voltage output not allowed to shortcut to ground. Although this device has overload and short circuit protection, we recommend that the users should work under the rated power value, in order to ensure the long-term stable operation of the device (voltage output should not short-circuit while the current cannot be open circuit). You CANNOT touch the voltage output terminal of the device by hand, to protect from electric shock. If there is something wrong with the device, please notify us of the maintenance, anyone without professional training is Not Allowed to disassemble the device. The power input terminal of the device can only use the standard 5A/250V fuse. When using this device, please keep the device grounding in order to ensure personal safety. There is grounding bolt behind the equipment which can be used for safety grounding. And you can also ensure the center line of the three-pronged power cable is reliable access to the earth loop already.