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Building Products July 2017

INDUSTRY COMMENT BLOWING THE FUSE ISSUE According to Tony Garlinge-Warren, it is time to consider 415V fuse protection rather than 690V. He argues that a failure to do so is both blinkered and limiting, imposes design constraints, and has cost disadvantages. 6 BUILDING PRODUCTS | JULY 2017 opportunity whereby 415V product can be switched in for existing 690V fuses, provided that the system voltage has been identified as 415V and that local regulations allow it. Too often a ‘like for like’ strategy is employed because approvals and paperwork say that this should be the case when technically there is no issue substituting 415V for 690V once the correct system voltage has been ascertained. Notwithstanding that 415V is the electrical three-phase standard voltage in the UK, there are in addition a whole hosts of benefits that accrue from choosing fuses of this rating. The industry will always talk about cost, and while unit prices of 415V products are likely to be less than comparable 690V products, it is cost in It is said that ‘old habits die hard’ and one need look no further for proof than the electrical industry’s continued preference for specifying 690V fuse links when, in most cases, 415V fuses would be as appropriate, if not more so. How entrenched are those ‘habits’? From the evidence we have, it would appear that they are deeply entrenched. For example, we estimate that in the UK 90% of all electrical commercial and industrial applications would suit 415V fuses yet there appears to be an unswerving loyalty to 690V fuses, that sees them specified in far greater numbers than the applications merit. One could argue that this is no bad thing, that an adherence to the original standard 690V product is the safest thing and that any change in rating might give rise to unnecessary issues. After all who wants to mend something when it is not broken? However, such an attitude is both blinkered and limiting, while also imposing design constraints and unwarranted cost. Suffice to say that continuing to specify 690V fuses when 415V products would be more than adequate in the majority of cases is overengineering, and with the attendant increase in component cost such as cables, is over-paying and ultimately a false economy. Maybe it is time to take a fresh approach and embrace the choice of 415V fuses as the premier rating for electrical circuit protection? After all, as stated above, roughly 90% of applications can be catered with 415V fuses. What should also be considered is the retrofit


Building Products July 2017
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