Patent ID: 8648688

Claim:
A protection element for protecting a device to be protected, the protection element comprising: an insulation baseboard; a pair of electrodes provided at both ends of a top face of the insulation baseboard; a low-melting metal conductor which is disposed on the insulation baseboard, and which is adapted to be connected to an electric power supply path of the device to be protected, wherein the low-melting metal conductor is adapted to cause a blowout by means of a predetermined abnormal electric power, and the protection element is adapted to allow the low-melting metal conductor to blow out and shut off a current path thereof if the abnormal electric power is supplied to the device to be protected; an insulation cover which is mounted on the baseboard so as to cover the low-melting metal conductor with a predetermined space therebetween; and a flux which is coated onto a surface of the low-melting metal conductor and is positioned in the space, wherein: the insulation cover mounted on the insulation baseboard is formed in a box shape which opens at one side face part; an opening portion comprising a through hole is formed in the insulation cover opposite to the low-melting metal conductor; the opening portion comprises a concentrically circular opening portion of a large diameter which is formed at a center part of the insulation cover and is arranged face-to-face opposite to a center part of the low-melting metal conductor; the opening portion is covered with a transparent film; the opening portion is formed so that a projection position for the insulation baseboard surrounds the center part of the low-melting metal conductor; the flux is arranged to be in contact with a peripheral edge part of the opening portion and is retained at the peripheral edge part due to its wettability and surface tension; and the flux is provided on the low-melting metal conductor so as to be retained at a predetermined position in the space.