Fuse problem notification.

[itsmoked]

A buddy recently told me about a great little fuse kit for automotive type fuses. Specifically the ATO and ATO mini blade type found in all new vehicles.

See:

http://photo.manufacturer.globalsou...e/product_id-1003030100/action-GetProduct.htm

I use them in a lot of my low voltage designs as they are easy for customers to change,(if ever needed!!).

I have a bit of a problem finding all the values I need so when he told me Harbor Freight(HF) has a kit for a mere $5 I checked it out. Sure enough their STOREHOUSE kit had 120 fuses in a nice divided case with equal parts of 5,10,15,20,25,30A fuses.

Wow! I picked up one case of the larger ones and two cases of the the smaller mini ones. I have used a few and shipped a prototype with some.

So now 3 months later I get a safety recall from HF. "Some may not work correctly".

Groan..

So me thinks, "How bad can these really be"? I could test them all but that would be like testing for being a witch. If it blows it was a good one,(I could've used), if it doesn't blow then it's bad,(one I can't use).

I also figure yeah so a few people had a bad experience.. If I test a few and they work perfectly I can decide on a statistical sample.

So I grab a 5A device and I hook it to my 200W lab supply. I set the current limit to about 2A and set the voltage to a couple of volts. I then turn up the limit until I hit 5A. I wait about a minute. Then I crank it up to 6A and wait a bit. My "typical" test leads start to get warm. I add another set in parallel. I wait. Then I turn it up to 8A. I wait about 30 seconds then turn it up to 9A. Now the two sets of leads are starting to slowly sag as they are getting pretty warm. The supply is humming threateningly, I can feel the vibration in the leads I'm holding. After about 2 minutes of this I can't take it anymore. I abort the test, figuring my PS is going to take a dump working 9A into <1V load.

So based on my statistical study.. 100% of them are bad because I'm not going to bother testing anymore.

Unless, any of you have special requests...


Of course further study shows: MADE IN CHINA on the front.

http://money.cnn.com/2007/09/05/autos/fuse_recall/index.htm?postversion=2007090516

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[zeitghost]

Ah yes.

The Chinese fuse thing...

"What BS number do you want printed on the side of this chunk of 6 inch nail in a ceramic carrier?"

Or variations on that theme.

Though I seem to remember that there's a I*t (or I squared t) curve for a fuse that you might find it useful to look up.

 

[DaveScott]

Reminds me of my apprenticeship days in the steel works: I noticed that to isolate an un-identifiable cable one dubious practice was to short it out, and rely on the fuse or circuit breaker to trip. That was until one 6 inch nail which had been hammered into the cable started glowing bright red and everything started smoking...must have been a chinese nail.

 

[mcgyvr]

a typical time curve for ATO fuses is
110% of the rated load (should blow in 100 hours max)
135% of the rated load (should blow in 600 seconds max)
200% of the rated load (should blow in 5 seconds max)

Here at my work if it says "made in china" we immediately try to find a cross made in a country with a better/any reputation for quality.

 

[itsmoked]

Thanks mcgyvr. I was curious about that.

So 9A thru a 5A fuse shouldn't have lasted a couple minutes huh? Ha!

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[jimkirk]

Clarification:

The 110% rating time is a MINIMUM time to open. There is no maximum time.

At 600% of rating, there is a maximum time to open, but no minimum.

Between these two there are specified ranges of opening time based on the percent of current rating.

Check the spec here for an example:

http://www.littelfuse.com/cgi-bin/r.cgi/en/prod_series.html?SeriesID=147&LFSESSION=1ZlgLFVlSK

 

[stevenal]

http://www.littelfuse.com/data/en/Time_Curve/257.tc.pdf

 

[IRstuff]

While the Chinese are undoubtly deserving of being slammed, they are hardly alone in screwing things up:

http://www.cpsc.gov/cpscpub/prerel/prhtml06/06231.html

TTFN

FAQ731-376

 

[VEBill]

257-series are "Fast-Acting Type" fuses.

I think that Quality Assurance would be a very good career choice in China right about now. Nowhere to go but up.

 

[peebee]

IRStuff -- a quote from the site you linked to:

"printed on the batteries: 'Made in Japan,' 'Made in China,' or 'Battery Cell Made in Japan Assembled in China.'"

Hardly alone? Maybe... but you could have picked a better reference than that to prove your point...

 

[itsmoked]

Hey jimkirk; Thanks for that clarification. And the link. Looks like that fuse should go in about 0.6 seconds @ 9A.

VE1BLL; You are soooo right!

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[IRstuff]

It was the cells manufactured in Japan that caused the problem:

http://www.sony.net/SonyInfo/News/Press_Archive/200002/00-0229/

TTFN

FAQ731-376

 

[TurboXS]

Keith,

Thanks for sharing this with us as it was quite interesting. I have passed it on to other engineers here.

regards
Peter

 

[itsmoked]

Sure Turbo!

I guess it's kind of a case of, "You get(deserve) what you pay for."

I was paying $5 for 3 or 4 of them and then along came a $5 for 120 of them. I didn't even think about it as being Chinese junk and a safety device.

Reminds me of someone's tale where they were at a Chinese trade show and saw some Molded Case Breakers that were insanely cheap but saw they were not UL. On mentioning that to the vendor the vendor said "No problem we can mold that onto the case!", missing the entire point.

I guess I need to, "just say NO", at this time to anything Chinese that is a last line of defense, safety device.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[TurboXS]

I did a search on this "wonderful" Storehouse brand and came across this review/test;

http://toolmonger.com/2007/02/16/test-to-destruction-crimp-terminals/#more-3745

As you say you get what you pay for..........however in the long run saving the cents cost you dollars when you look at the overall cost in recalling the product and the additional damage a faulty part can cause.

 

[VEBill]

On the subject of cheap knock-offs...

My kids have Nintendo DS portable game systems. The systems came with 'approved-by-everyone' AC Adapters that were designed only for 100 to 120 volts AC input (not usable with 240 volts AC). We were going to Asia for a vacation and needed some AC Adapters that could also accept 240 volts AC, so I bought some on-line from an outfit in HK. Very cheap. Free shipping. They were not approved by anyone.

On the outside, the two types of adapters (approved vice unapproved) were nearly identical (except for the approval markings, not present on the unapproved unit). I peeked inside both types and what a difference!

The approved unit had nice sliding contacts for the rotating swing-away AC plug. It was a barrier design where the HV was kept away from the 5 volts. It appeared to be top quality in all respects.

The unapproved unit had twisting wires for the swing-away plug. There was no barrier on the circuit card. The card and components looked cheap. Many unmarked components.

To quote my coworker: "Things are cheap for a reason."

Oh, for the trip, I eventually found an approved adapter that would accept 100 to 240 volts AC.

 

[itsmoked]

Thx Turbo.

I didn't even realize that HF had "Storehouse" as a brand. I will steer far away from it now on. Must be some guys sitting in a room asking,"How cheap can we make this but have it look like the real thing?"

May the fleas of a thousand camels infest their nasal passages.

Good on you VE1BLL for taking the initiative. I'd be nasty holding an exploding Nintendo with 240 reaching it.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com