fuses - the $39 ones or the 85 cent ones

Agreed that a fuse 'should never fail to fail'.
I wonder what the truth of certification (UL, SA, etc) is?

A REACH: I suspect it costs a Bundle to get a certification.
YOU, the manufacturer pay for the tests and must supply all the samples. In the automotive world, that is how it is for motor oil. There is some non-certified oil out there which is also very good. A few types of Amsoil used to be like this.

Now, manufacturing can also be certified. The company I work for, in semicondutor processing, undergoes periodic Independent Audits. We are also ISO certified. If the HiFi-Tuning fuse folk are so certified, I would not hesitate to purchase there stuff....Of course, I still think that 39$ for a fuse of only anecdotal help is ridiculous. But, if they have undergone independent audits OR are ISO certified, than I believe the fuse would indeed act like a fuse.

It would than be up to the Lawyers to decide....in the event of some kind of failure causing damage to life or property.

As for being 'manufactured under some sort of oversight by an independenty agency' ?? I hope you Do Not mean Government? If those guys made cookies, we'd all be dead.

Magfan, not to pick on you again. But ISO does not guarantee that a fuse will work like a fuse. It is a process certification, not a product certification.

Very true about ISO.....and good catch!
ISO basically says that you 'say what you do' and 'do what you say'....In other words, you follow your own internal specifications and documents.
They could care less if it actually works!

I don't know how costly it is to have UL listed or any other certification, but during my search all 2.5A and 4A fuses have UL and SA certification, except of course for HiFi-Tuning fuses. For instance, the Isoclean fuses have UL SA PSE and CE certifications, the Littel Fuse fuses have UL, SA and CE certifications, and Buss fuses have UL and SA.

It seems to me that they pursue the certification in the market in which they will be distributed. I don't know the certification story of HiFi-Tuning, but if they have it, it is odd that they don't post it like everybody else.

Couple 'o thoughts.
I would suspect you are right: get the certs of the market you intend.
Small companies, even those making, say, 10,000%, probably can not afford such certs.
If, BIG IF, HiFi-Tuning is small, like 3 or 4 employees who would usually all be relatives and owned by 1 guy, than I would expect no certs, now or in the near future. This, in and of itself is meaningless. When's the last time somebody Sued UL for a product fault?

I don't know how to do the numbers here, but if HiFi-Tuning could make more fuses and drop the price, his profit could actually increase. Of course, the market for 20$ fuses is probably not double that for 39$ fuses, so he may lose and end up with a garage full of un-sellable fuses.

Many other approaches, too. Like getting a couple OEM contracts......make fuses for BigTime players. Of course they'd hammer him to death for a low price, but his name would be out there in wider distribution.

Happy Listening.....