Ferraz Shawmut Welder Protectors are special purpose limiters used to provide isolation of faulted welding equipment and protection for the cable drop supplying the welder. Welder Protectors have a high thermal capacity and are less affected by high ambient temperatures and extended weld times than similar size Class J, K, or R fuses*. Welder Protectors should only be applied for isolation of short circuited welding circuits. Overload protection must be provided for by other means.