Transient voltage surge suppression module with ultrafast fusing

A transient voltage surge suppressor for use on a single or poly-phase power distribution network to protect equipment supplied power from the network from damage caused by line surges or transients comprising:

• a plurality of surge suppression assemblies each of which includes a plurality of semiconductors connected in parallel and a fuse wire connected in series with each semiconductor, each surge suppression assembly being mounted on a separate circuit board, and a surge suppression assembly being connected between the "phases";
• fault detection means including means for sensing when a semiconductor in one of the surge suppression assemblies fails, or when a fuse wire in one of the assemblies blows, and means for providing a visual indication thereof, said fault detection means being mounted on a circuit board separate from the other said circuit boards,
• a module in which the respective circuit boards are installed, the circuit boards on which said surge suppression assemblies are mounted being installed parallel with each other, and the circuit board on which said fault detection means is mounted being installed at an angle thereto;
• and,
• plasma suppression means for preventing spread of a plasma produced when a semiconductor fails or a fuse wire clears, said plasma suppression means including a sand with which the module is filled thereby to substantially completely fill the spaces between the circuit boards on which the surge suppression means are mounted, and an epoxy material with which any remaining space in the module is filled alter the sand is poured into the spaces between said circuit boards and after said circuit board on which said fault detection means is mounted is installed in the module.