Fire pump controllers, assemblies of electronic and electrical devices, are intended to ensure critical life-safety operation of fire-fighting pump motors in buildings. If the pump motors or the controllers fail to operate, there is significant potential for loss of life and loss of buildings and their contents. Why would anyone write a regulation that could hamper the ability to provide protection against fire?
There is a need for electrical current protection to ensure the controller circuits and the motor do not fail prematurely. The use of fuses only is an installation requirement included in the European Norm 12845 (not a product standard), while similar US requirements ( in NFPA 20 ) prohibit the use of fuses for overcurrent protection of fire pump controllers. (Fuses when used in the right application provide excellent electrical current protection.) Why would fire protection be compromised by using a fuse on the supply to a controller and pump? Because replacement of the fuse in an emergency situation would be difficult if not impossible for firefighters. NFPA 20 recognizes that opening of a single fuse could prevent the flow of water through the sprinkler system.
During the development of IEC 62091 for Fire Pump Controllers, the arguments against fuses were made on a regular basis but the responsible authorities for EN 12845 would not consider a change, even given the safety ramifications. The IEC 62091 standard was developed with strong US participation, was approved by IEC SC17B membership and includes many requirements consistent with those used for US certification, contained in Underwriters Laboratories UL 218. Even the Factory Mutual Global standard FM 1321/1323 makes reference to IEC 62091. Why does the European specification EN 12845 not reference IEC 62091 and eliminate the ill-advised use of fuses in this application?
European authorities need to rethink their requirement. Surely they are as interested in protection of people and buildings as we are in the US. What am I missing?? Maybe there is a reason for continuing to specify the use of fuses in this application but I am certainly more comfortable knowing that the US practice includes resettable protection and product certification for the Fire Pump Controllers used as part of the system to provide water to building fire-protection sprinklers.