I've not had that unhappy experience, however, one of our guys was badly injured when a Cooper Bussmann fuse base blew up in his hand. I'm relaying this story so others can learn from this.
Our electrician had replaced a blown 30 amp 480 volt fuse in this three phase fuse pull out. See the attached pdf of this fuse holder. He was installing the fuse back into the base when it shorted and blew up in his hand. His right hand and forearm were burned (second degree). Fortunately, his face was not burned.
Why did the fuse base short out? I don't know for sure, but have ideas. I believe the contacts inside the body of the fuse holder connected before the barriers between the connections were fully seated. That would allow any spark to propagate to the next phase. I believe that is what happened here.
One problem I found was the actual warning label on the fuse holder. In this case, the warning language was written behind the handle. Further, it was written in about 6 point font. The small font was difficult for me to see and hard to read. The warning said something like "do not remove under load". That may not be the exact wording, but it's close. I thought the language was odd.
During the deposition, their attorney asked me why our electrician did not shut the power off? I explained that in our world, meaning an electrician's world, if you've removed a pull out or fuse holder, it is off.
Please have a look at the attached pdf. I'd also urge you to let your crews know that if and when dealing with this particular fuse holder, that power MUST be turned off before removing or installing the fuse holder.
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File comment: Obsoleted fuse base
SHEET SHOWING THE FUSE BLOCKS ARE OBSOLETE.pdf [50.69 KiB]
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