A TFD fuse holder includes a GMT fuse, to allow for alarm circuitry activation in the Telect power panel. The GMT fuse is not part of, nor should it be used for equipment protection. The GMT fuse is only for activating the alarm circuitry and uses a 0.18A rated GMT fuse. Normal operation for the TFD fuse holder is once the TPS or TLS fuse blows the line current goes thru the GMT fuse, which will cause it to blow instantaneously and have the GMT flag activate the alarm circuitry. At this point the panel is no longer using line current, but the alarm board current. The line current has been interrupted by the blown main fuse and the blown GMT fuse. For this reason Telect strongly recommends that no equipment is powered by the Telect panel, until a TPS or TLS fuse is installed into the TFD fuse holder. Also, Telect strongly recommends no GMT fuse rated higher than 0.18A is installed into the TFD fuse holder. This is industry standard practice for TFD fuse holders, and is not a Telect specific design.
Operating the Telect panel with a GMT fuse rated higher than 0.18A may void the panel warranty.