What good is an 601a. fuse?

Meant to 601a in the Subject line :0

[This message has been edited by George Little (edited 12-05-2005).]

A question I have asked myself more than once.

I hope an answer is presented.

The only other reference I see is in 430.52ex2(d) and the necessity of 601a doesn't really make sense.

Are they really saying I could use a 601a time delay Type L fuse at up to 300% of FLA vs 175% for 600a or less? (when the rest of 430.52 Ex1 & Ex2 is met)

I don't know and I have never seen a 125 HP motor

AFAIK, the 601A fuse is used when you want to fuse an 800A disconnect at 600A.

Essentially, a 600A fuse in the 800A package.

We have an IAEI Seminar 12/8 & 9 and the Bussman rep is scheduled to be there. I'll bounce it off him and bring back the info.

I have been told that the after 600 amps, the physical size of fuses changes. If you have equipment that willonly accept fuses greater tahn 600 amps, but you want 600 amp protection, you use a 601 amp fuse.

Ryan that makes sense but why do we not have 101, 201, 401, 801 amp fuses as well for the same reason?

because they make adapters for the smaller sizes?

???

...from the ECN Archives ...
(Dan Neeser is from Bussmann)
https://www.electrical-contractor.net/ubb/Forum1/HTML/001080.html

[This message has been edited by Bill Addiss (edited 12-08-2005).]

Earlydean:
I had the same thought as you, but thought it out again.

Not having a Bussman Catalog handy, does not a 601 amp fit an 800 amp disco, and the 801 fits the 1200 amp disco I'm familiar with the adaptors for 30-60-100-200 sizes, and never seen anything larger.

'601' is referenced within 240-6 (A) but '801' is not.

Now that I said all of that......still??????

jOHN

Here's the deal per the Bussman rep. The contractor could install a 800a. or 1200a. Safety Switch with conductors that were only adequate for 600a. Now if the customer decides to expands his capacity to 800 or 1200 amps all he needs to do is change the conductors and the fuse and not have to change the switch. This is apparently is a significant cost saving measure. From what Bussman is telling me, it's the only "Listed" way of doing this sort of thing. Works for me.

I have seen this done with 400a equipment and 225a fuses. It bothered me so much I have a proposal in the 1999 ROP.
CMP10 said nobody would be dumb enough to shove a 300 or 400a fuse in there without upsizing the conductors so it wasn't a problem. I guess they never saw a "maintenance man"/electrician.

Has CMP 10 never seen pennys in the fusebox? Or copper pipe in the fuse holder? Or even #12 copper wire jammed into the fuse holder or meter socket?