National Electrical Installation Standards

Standards as High as Your Own

Monday, September 2, 2019


I recently attended an Arc Flash training class and the instructor spent a lot of time giving his personal opinion rather than delivering information. The issue of fuse reducers came up and he said they were illegal since the 2006 code or some such nonsense... he never could tell me why and got really agitated when I asked for more information. I have looked them up on the manufacturers site and they are UL listed and I cant find anything in the code telling me they have been banned. Do you have any information?

Travis Crockett


Hey Travis thanks for your question. There are some electrical trainers that maybe shouldn't be, just as there are many who do, or try to do, electrical work that are not qualified. There is a 2005 NEC and a 2008 NEC but no 2006 so maybe they are referring to a different code, a company or design specification, or maybe they heard it from someone who heard it from someone who made it up.

Fuse reducers are not prohibited by the NEC nor are they specifically addressed. The guide information for Fittings for Fuseholders, IZZR at indicates that "Consideration should be given to spacings when fuseholders are used within enclosures." Listed fuse reducers are available and as always the manufacturers instructions must be followed as stated in 110.3(B). If any fuse manufacturer or testing laboratory representative has more information please send it in and we will publish it.

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