100HP MCC Used for a 100 Amp Disconnect

[Mushroomman]

At my work our electrical contractor repurposed and converted a new 100HP FVNR starter (MCC mounted) to a 100 amp disconnect. The 100HP starter has 200 amp fuse clips (actually set screw compression clamps). So, to make it work for the 100 amp fuses, the lower fuse clips had to me moved up to accommodate the shorter fuses. No holes were needed to be drilled as this MCC starter had multiple factory mounting holes. So it was not modified, per se'.

Is there any issue with code on this?


Back ground - Reliability had an IR call on this "disconnect" for a hot spot on the A phase line side fuse clip and said it was because of the wrong size fuse clips. I said the "Larger" fuse clips would actually be better but I would need to find out if it against code.

 

[petersonra]

At my work our electrical contractor repurposed and converted a new 100HP FVNR starter (MCC mounted) to a 100 amp disconnect. The 100HP starter has 200 amp fuse clips (actually set screw compression clamps). So, to make it work for the 100 amp fuses, the lower fuse clips had to me moved up to accommodate the shorter fuses. No holes were needed to be drilled as this MCC starter had multiple factory mounting holes. So it was not modified, per se'.

Is there any issue with code on this?


Back ground - Reliability had an IR call on this "disconnect" for a hot spot on the A phase line side fuse clip and said it was because of the wrong size fuse clips. I said the "Larger" fuse clips would actually be better but I would need to find out if it against code.

I don't know if you can use the same fuse clips or not. I would check on that first. It should not be real hard to check.

In general I don't have an issue with removing the motor starter and replacing fuses/fuse blocks to repurpose the bucket.

 

[Mushroomman]

I don't know if you can use the same fuse clips or not. I would check on that first. It should not be real hard to check.

The original 200 amp fuse clips can accommodate the 100 amp fuses. They are the same design but slightly larger, i.e. more mating surface on the originals. The problem is I can not find anything in the 2017 code that states this can not be done. Here at work, I have to show facts, and having a code section to quote is what I need.

I have the new code book in pdf and can search for specific words and nothing come up. I have even read page for page in the sections I would think that would pertain to this and still nothing.:happysad:

 

[don_resqcapt19]

Why would you modify the equipment when you can just buy fuse reducers designed for the purpose? I believe that the blade on a 200 amp fuse is thicker than the one on the 100 amp fuse, so that could reduce the contact pressure and increase heating at the point of connection.

 

[petersonra]

I don't know if you can use the same fuse clips or not. I would check on that first. It should not be real hard to check.

The original 200 amp fuse clips can accommodate the 100 amp fuses. They are the same design but slightly larger, i.e. more mating surface on the originals. The problem is I can not find anything in the 2017 code that states this can not be done. Here at work, I have to show facts, and having a code section to quote is what I need.

I have the new code book in pdf and can search for specific words and nothing come up. I have even read page for page in the sections I would think that would pertain to this and still nothing.:happysad:

I don't think you are in a position to pass judgement on the appropriateness of using the fuse clips for something other than what they were designed for. That is the job of UL.

You are not going to find a general rule that prohibits one from making modifications to equipment.