Abstract: An adapter having a middle shell; a plug shell and an upper shell are provided respectively at a front end and a rear end of the middle shell; a rear end of the upper shell is provided with a wire; a rear end of the wire is connected with a plug element; a left side of the middle shell is provided with insulating plate; a left side of the insulating plate is provided with cooling fins; a right side of the middle shell is provided with a printed circuit board assembly (PCBA). The middle shell, the upper shell and the plug shell are all made of PC fireproof materials. The wire is made of PVC fireproof materials. The cooling fins are made of brass. The insulating plate is a PC insulating plate. The PCBA is made of glass fiber. The plug element is made of stainless steel.