What do HRC, reaking capacity and ime current curve mean?
‘HRC’ and ‘breaking capacity’ mean ‘high rupturing current’ or more commonly, ‘high breaking capacity’. This is a fuse link, the body of which is usually made from a high-grade ceramic or composite material and an interior filled completely with sand, which has been tested to safely interrupt very high fault or short circuit levels of current. An IS: 13703 fuse link is tested to 80kA (80,000 amps) without it physically exploding or suffering external damage. The fuse link will clear the fault and be left open circuit afterwards. This is said to be a ‘HRC’ or ‘high breaking capacity’ fuse link. Consequently, most small dimension glass fuses are ‘LBC’ or ‘low breaking’ capacity. ‘Time Current Curve’ is the data used to check if a given fuse link will cope with, for example, starting a motor. The data can also be used to check discrimination between fuse links. The vertical axis of the graph displays time (in seconds), the horizontal axis displays current (in amps). The curved line depict
