Fuse Bolts

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xguard

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Baton Rouge, LA
I've come across several installations with fuses in the range of 800 to 1200 amps, I believe class L, that have multiple mounting holes for bolts on each end of the fuse. Often there is only one bolt installed on each end. I'm assuming each hole needs a bolt unless this is to account for variations in equipment, seems like it would be standard though. I've looked on various manufactures websites and haven't found instructions for mounting such as; how many bolts, what size, torque (even though I personally haven't seen an electrician with a torque wrench yet). Can anyone clear this up for me. Thanks for any feedback.
 
I would think that if the fuse is correct for the mounting stabs then it would have holes for the proper number of bolts. Are you saying that the fuse has, for example, two holes on each side but only one bolt is installed on each side of the fuse?

Just for the record I torque fuses 100% of the time. (y)
 
infinity said:
I would think that if the fuse is correct for the mounting stabs then it would have holes for the proper number of bolts. Are you saying that the fuse has, for example, two holes on each side but only one bolt is installed on each side of the fuse?

Just for the record I torque fuses 100% of the time. (y)
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Yes there's two holes on each side but only one bolt installed on each side.
 
xguard said:
Yes there's two holes on each side but only one bolt installed on each side.
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IMO there needs to be a bolt in each hole because that's the way the manufacturer designed it. It's like saying you only need to put in 1/2 the bolts when bolting together the bus bars in switchgear. In this photo (ignore the 800 amps fuses as they are just temporary) of a 2000 amp switch it's clearly designed for two bolts in each fuse when the correct fuse type is installed.
Fused Switch001.jpg
 
Not familiar enough with these to know all the details, but thinking you could have a 800 amp fuse or a 2000 amp fuse of same physical dimension it seems possible the 800 might only require use of one bolt (per end) where the the 2000 would require using two? At what point in between you need to change might be dependent on equipment it is mounted to.
 
kwired said:
Not familiar enough with these to know all the details, but thinking you could have a 800 amp fuse or a 2000 amp fuse of same physical dimension it seems possible the 800 might only require use of one bolt (per end) where the the 2000 would require using two? At what point in between you need to change might be dependent on equipment it is mounted to.
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I'd say the number of holes in the fuse blade determines how many bolts should be used.
 
LarryFine said:
I'd say the number of holes in the fuse blade determines how many bolts should be used.
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Maybe also the number of holes in the fuse holder.

Look at image in post 4. Pretty heavy bar link on top side four bolts holding it to the bus one bolt connecting the fuse. May or may not be what the manufacturer intended but still more holding the top side than if there were two bolts in the fuse side.
 
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