Fuse retention clips

[wrobotronic]

This could probably go to the NEC section also. But my question is when are fuse retention clips required? My AHJ cites 240.60B for this. While I might have the name wrong, these clips are basically a screw that keeps the fuse in place so it doesn't move. But I read that section differently and really don't understand why these are required per this section. As always, thank you.

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[iwire]

This could probably go to the NEC section also. But my question is when are fuse retention clips required? My AHJ cites 240.60B for this. While I might have the name wrong, these clips are basically a screw that keeps the fuse in place so it doesn't move.

240.60(B) has nothing to do with screws that hold the fuse in place.

That has to do with different mounting to prohibit putting the wrong fuse in place.

 

[wrobotronic]

That's my interpretation also.

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[kwired]

I think I know what clips you are talking about. I don't think they are required to be used at all, but rather are an item that can buy you some time before you need to replace the fuse holder (or more likely the entire assembly) in cases where the fuse holder has lost some of it's spring tension that is supposed to otherwise be sufficient to maintain a good connection between the fuse and fuse holder.

 

[infinity]

240.60(B) has nothing to do with screws that hold the fuse in place.

That has to do with different mounting to prohibit putting the wrong fuse in place.

I agree. I'm not sure why the AHJ in the OP would think otherwise.

 

[jim dungar]

I think I know what clips you are talking about. I don't think they are required to be used at all, but rather are an item that can buy you some time before you need to replace the fuse holder (or more likely the entire assembly) in cases where the fuse holder has lost some of it's spring tension that is supposed to otherwise be sufficient to maintain a good connection between the fuse and fuse holder.

Most manufacturers say these screws are to keep fuses from vibrating out of the fuse clips, these devices are not intended to compensated for clips with poor contact strength.
Have you ever seen instructions providing proper torque values?

 

[kwired]

Most manufacturers say these screws are to keep fuses from vibrating out of the fuse clips, these devices are not intended to compensated for clips with poor contact strength.
Have you ever seen instructions providing proper torque values?

Never saw the instructions for the ones I have seen. They have what looks to be a handle intended to be tightened with your hand - but we all know how much torque we are providing when using just our hand to tighten something don't we?

Or are we not talking about the same item?

Here is link to what I was talking about

http://www.cooperindustries.com/content/public/en/bussmann/electrical/products/accessories/tron_clip-clamps.html

Not much information there on installation or intended use other then the mentioning of "Provide tight contacts between fuse holder clips and fuse ferrules/blades"

 

[jim dungar]

Not much information there on installation or intended use other then the mentioning of "Provide tight contacts between fuse holder clips and fuse ferrules/blades"

It must be my age.

I see Mersen also says:
"This helps prevent loss of spring tension due to annealing from overheating"