Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The Downfall of Amazon: Top Ranking Electrical Fuses Show Dangerous Results [video]

youtube.com

Post reply on HN
Print view View original

41–50 of 64 posts

Re: The Downfall of Amazon: Top Ranking Electrical Fuses Show Dangerous Results [video]

#41

Post by blagie »

postpawl wrote: post #21
blagie wrote: post #15

For the record: Some of these are a bit over-the-top, and Amazon is trash for anything safety-related, but for the record, virtually all fuses have a pretty significant margin before they blow. The risk here is very limited: - A 2A fuse needs to conduct 2A, no matter ambient temperature, manufacturing variation, age, etc. - 95+% of the time, what you're protecting from isn't a minor overload condition but a short. Th…

I saw an example of this recently during the test of some large DC fuses for solar: https://youtu.be/6o9tbhgtws4?feature=shared Some are slow burn fuses and don’t pop until you exceed the rated amperage for a long time and by a lot of amperage. Not really what I expected. Some of the fuses do work like you’d expect and pop when they exceed the amperage by a minor amount.

When I was a student, my lab professors had a saying: "Sometimes a fuse will blow to protect the circuit, and sometimes the circuit will blow to protect the fuse."

One problem is that fuses are thermal devices. They break due to overheating. They take a while to warm up and blow. If a fuse overheats at 2A at 100ms, it will get that same amount of energy at at 20A over 1ms, which is an eternity by the standards of transistors.

Most silicon devices can destroy themselves in milliseconds or microseconds.

Re: The Downfall of Amazon: Top Ranking Electrical Fuses Show Dangerous Results [video]

#42

Post by doodlebugging »

Amazon sells so much crap. All those companies with nonsense names selling the exact same products with the the same verbage and photo spreads and only a few dollars different in price should tell you all you need to know.

Quality issues apparently have become so bad for them that they no longer want the defective item to be returned. It is yours to dispose of in any way you see acceptable. They will refund your money or ship a new product but they don't want the failed item. This has been true for me with garden planters, electrical components like pliers, crimpers, and lugs, automobile parts, and solar installation components. Every item that has failed or been found to be unfit for the purpose yielded a refund and a note that it is not necessary to return the failed item.

I review many of the products that I buy and give honest reviews. I also answer customer questions about items I have bought even if the answer they need is in the product description. I think so many people have lost trust in Amazon that they need to know whether descriptions are accurate or hype. It is impossible to tell just from reading reviews and when Amazon shows multiple Amazon is broken and I am trying to get my wife to quit buying so much shit from them. I buy most auto parts, hand tools, etc from their manufacturer sites. I can trust things to be fit for purpose and durable.

Re: The Downfall of Amazon: Top Ranking Electrical Fuses Show Dangerous Results [video]

#43

Post by rightbyte »

blagie wrote: post #15

For the record: Some of these are a bit over-the-top, and Amazon is trash for anything safety-related, but for the record, virtually all fuses have a pretty significant margin before they blow. The risk here is very limited: - A 2A fuse needs to conduct 2A, no matter ambient temperature, manufacturing variation, age, etc. - 95+% of the time, what you're protecting from isn't a minor overload condition but a short. Th…

No.

https://www.nilight.com/products/nilight-272pcs-standard-min...

These are not slow burning fuses or whatever. In their product video 6A blows a 5A fuse in like subseconds. However 6/5 rated current should probably blow slower, like days, or not at all? The 2A fuse is probably just made faulty.

Edit: Of course, the Amazon seller could be a counterfeit of "Nilight", which might be a proper brand?

Re: The Downfall of Amazon: Top Ranking Electrical Fuses Show Dangerous Results [video]

#44

Post by blagie »

lnsru wrote: post #28
blagie wrote: post #15

For the record: Some of these are a bit over-the-top, and Amazon is trash for anything safety-related, but for the record, virtually all fuses have a pretty significant margin before they blow. The risk here is very limited: - A 2A fuse needs to conduct 2A, no matter ambient temperature, manufacturing variation, age, etc. - 95+% of the time, what you're protecting from isn't a minor overload condition but a short. Th…

In addition to other things I am certified electrician in Germany. Your claims are wildly oversimplified. Every fuse has a type, rating and trip current. I pick them by planned application, installation type and cable length. Copper cables cost money, the safety margin is THE fuse. Otherwise cable insulation gets too hot and wears too fast.

Is English your native language? You might be confusing fuses with breakers.

Fuses aren't typically used to protect copper runs; breakers are. Fuses are used inside of electronics. Breakers are rated as you describe, to protect copper runs.

For fuses, this is a data sheet of a random fuse (first one on Digikey search; I didn't pick anything special):

https://www.vishay.com/docs/28747/mfuserie.pdf

Re: The Downfall of Amazon: Top Ranking Electrical Fuses Show Dangerous Results [video]

#45

Post by FireBeyond »

blagie wrote: post #15

For the record: Some of these are a bit over-the-top, and Amazon is trash for anything safety-related, but for the record, virtually all fuses have a pretty significant margin before they blow. The risk here is very limited: - A 2A fuse needs to conduct 2A, no matter ambient temperature, manufacturing variation, age, etc. - 95+% of the time, what you're protecting from isn't a minor overload condition but a short. Th…

> Everything carrying current typically has a ton of safety margin built in, so even 2x isn't really a big deal.

Unless of course you _also_ bought it from Amazon, in which case, who knows?

Re: The Downfall of Amazon: Top Ranking Electrical Fuses Show Dangerous Results [video]

#46

Post by rightbyte »

blagie wrote: post #44
lnsru wrote: post #28

Earlier quoted context omitted.

In addition to other things I am certified electrician in Germany. Your claims are wildly oversimplified. Every fuse has a type, rating and trip current. I pick them by planned application, installation type and cable length. Copper cables cost money, the safety margin is THE fuse. Otherwise cable insulation gets too hot and wears too fast.

Is English your native language? You might be confusing fuses with breakers. Fuses aren't typically used to protect copper runs; breakers are. Fuses are used inside of electronics. Breakers are rated as you describe, to protect copper runs. For fuses, this is a data sheet of a random fuse (first one on Digikey search; I didn't pick anything special): https://www.vishay.com/docs/28747/mfuserie.pdf

In many houses porcelain fuses are still in use instead of breakers.

Re: The Downfall of Amazon: Top Ranking Electrical Fuses Show Dangerous Results [video]

#47

Post by blagie »

rightbyte wrote: post #43
blagie wrote: post #15

For the record: Some of these are a bit over-the-top, and Amazon is trash for anything safety-related, but for the record, virtually all fuses have a pretty significant margin before they blow. The risk here is very limited: - A 2A fuse needs to conduct 2A, no matter ambient temperature, manufacturing variation, age, etc. - 95+% of the time, what you're protecting from isn't a minor overload condition but a short. Th…

No. https://www.nilight.com/products/nilight-272pcs-standard-min... These are not slow burning fuses or whatever. In their product video 6A blows a 5A fuse in like subseconds. However 6/5 rated current should probably blow slower, like days, or not at all? The 2A fuse is probably just made faulty. Edit: Of course, the Amazon seller could be a counterfeit of "Nilight", which might be a proper brand?

Proper brands are not "Nilight" but companies like Vishay, Littelfuse, Eaton, Bel, Bourns, and similar.

Those brands can be found on sites engineers shop on, like Digikey, Mouser, Newark, and similar (which also lets you price / order by the thousands, and feed into manufacturing channels, rather than by boxes of random parts). They will have datasheets, rather than Youtube videos. Better datasheets will often show:

* Typical and worst-case behavior

* I²t, which is used to compute how long it will conduct a given current

* Impact on ambient temperature on rated current

... and similar

Here's a few random fuse data sheets from Mouser:

https://www.mouser.com/datasheet/2/54/SF_1206HH_R-3304051.pd...

https://www.vishay.com/docs/28747/mfuserie.pdf

https://www.eaton.com/content/dam/eaton/products/electronic-...

Some of these are more complete, and some less. That's a fact of life. I can buy a fancy fuse which specs and tests everything for a bit more $$$ for a medical or military application, or one which doesn't for $ for e.g. a toy. If all I'm worried about is a short, that's good enough.

A Youtube video which shows a 5A fuse blowing at 6A means either:

1. The video was baked for Youtube.

2. The fuse will blow at 4A on a hot summer day, running in an even hotter enclosure, and you've bought a bad fuse.

My bet is on #1.

Re: The Downfall of Amazon: Top Ranking Electrical Fuses Show Dangerous Results [video]

#48

Post by BenFranklin100 »

Amazon should reverse the changes it made to the reviews and let people respond to individual reviews again. Self-policing will improve the value of reviews as fake and biased reviews will be more easily identified by the community. When Amazon got rid of that feature (for cost savings presumably), it marked the beginning of the downfall of Amazon as a source for reliable product information and quality.

Re: The Downfall of Amazon: Top Ranking Electrical Fuses Show Dangerous Results [video]

#50

Post by fleventynine »

alangibson wrote: post #18
wmidwestranger wrote: post #11

Earlier quoted context omitted.

So true. I just had two Meanwell PSUs from Amazon delivered and the package was indistinguishable from the usual AliExpress job.

Are you saying they were fake? I've started getting all power electronics from Digikey, Mouser, RS, Pollin etc. because of paranoia over a crap power supply or SSR.

Likewise. A friend was almost killed a few years back by a counterfeit SSR purchased on Amazon. I would love to see them take some legal responsibility for the lethal garbage they let onto their platform.
Post reply on HN