Backward Fuses

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kbowman

Member
Does anyone know if it is a code violation to install fuses backward?

It seems like it should be.

The 'C' shaped stabs on the fuses are designed to go in one way.

Also, if they are backward, you can't read any of the data.

I looked through 240 and 110, but I could not find anything on it.
 

Jomaul

Senior Member
Location
Ocala, Fl
What we have done in the past is install 1 fuse 1 way and the other fuse backward so you can see what was on the front and back of the fuse without removing them. We never had a problem with it
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
The C shaped cut in one end of the fuse is a rejection feature to keep you from installing the wrong type fuses in the disconnect. If the fuses fit in either way then the rejection feature isn't present. Those fuses can go in either way. Since you should be opening the switch when it's de-energized you could pull the fuse out to see the label. I always install them label out. I like to think about the next guy.:wink:
 

royta

Senior Member
infinity said:
Since you should be opening the switch when it's de-energized you could pull the fuse out to see the label.

Good call. Nobody opens a disconnect without first throwing the switch. Never, ever, never. :)
 

mikeames

Senior Member
Location
Germantown MD
Occupation
Teacher - Master Electrician - 2017 NEC
This makes me think back. A few months back we were working on a FPE swith gear. We opened a bucket switch and pulled out the fuse with the disco off. The whole inside of the switch crumbled "Old bakelite plastic".....This overheating problem was the reason we were there..... Any way when we did that the fuse touched the line side bus inside.... It was now hanging there live and there wasn't much we could do since the restaurant was in service we couldn't shut down the switch gear to repair it. We carefully put scotch pads around it so it wouldn't fall and blow up the gear and take out the 1600 480v disco feeding the gear. The next day we went back and fixed it.

This forum helped me find a good resource to find replacement FPE bucket switches.
 

certir

New member
Location
NJ
royta said:
Good call. Nobody opens a disconnect without first throwing the switch. Never, ever, never. :)
Infrared inspections always require us to open disco's while energized. Of course we have all opened them while troubleshooting, thats why they put that little interlock defeat there in the first place.
 

Bea

Senior Member
Some fuse bolt in for inspection purpose I would be inclined to install fuse to display CIR, class of fuse, voltage and ampacity
 
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