The North American fuse industry has developed a number of Classes or Standards for fuses with voltage ratings of 600 volts or less. These classes include basic physical specifications and performance requirements.
|Class CC||600V; up to 30A; 200kA Cylindrical contact, 10 x 38mm with rejection feature.|
|Class G||300V; up to 60A; 100kA Cylindrical contact, 10mm diameter|
|Class H||250 and 600V; up to 600A; 10kA NEC* dimensions.|
|Class J||600V; up to 600A; 200kA Non interchangeable dimensions|
|Class K||250 and 600V; up to 600A; 50, 100 or 200kA NEC* dimensions.|
|Class L||600V; 601 to 6,000A; 200kA Bolted connections.|
|Class R||250 and 600V; up to 600A; 200kA. NEC* dimensions; rejection feature.|
|Class T||300 and 600V; up top 600A; 200kA Compact dimensions, fast acting.|
* NEC dimensions — National Electric Code dimensions, often referred to as Code Dimensions.