Necschott sfr series sefuse thermal cutoffs axial nec schott sf70r1 a 73c thermal fuse that uses an organic thermosensitive pellet inside a metal case features a large rated current of up to 15a 250v ac the device contains a sliding contact springs and a thermal pellet inside a metal case when the spring is compressed firm contact between one lead and the sliding contact occurs at normal temperatures current flows from the lead to the sliding contact and then through the metal cas