Harbor Freight Fuses

[jos51700]

Harbor Freight fuses...

The second from left on the bottom row got hot enough the plastic melted completely off (and melted the fuse block too), and the fuse was still intact and carrying enough current to melt a bunch of wires! (It was a 10Amp circuit, but it had a 15 amp fuse, carrying a 20Amp load). You can still see the blade of the fuse in the holder, and a blue gob of plastic at the bottom of the fuse block.

The yellow fuse you can see is all puffed out and melted, too, and it's the proper fuse for its' circuit. It melted, blew a big plastic bubble, and it's not blown, either!

Saving a buck on fuses (exacerbated by shoddy wiring practice for accessories) nearly cost this guy a full-custom Kawasaki Mean Streak, and will cost him a $300 wire harness for sure!

I know that our old Mopars don't use many of these fuses, but you can get all kinds at HF, and a lot guys run modern wiring. This is one HF item to skip!

 

[roadrunnerh]

Not trying to defend HF but the wiring could have been the major problem....

 

[67Dart273]

I agree. This could go either way, and it's possible that the fuse was out of spec BUT............

When a fuse has a problem, IE an internal loose connection, usually the fuse just blows because of self--generated heat

If the fuse was "out of spec" then nothing much should have happened, unless the circuit overloaded, so I guess that's possible.

My first "jump" is that there's a bad connection at the fuse connector, and or the circuit is severely overloaded.

 

[jos51700]

Not trying to defend HF but the wiring could have been the major problem....

I agree. This could go either way, and it's possible that the fuse was out of spec BUT............

When a fuse has a problem, IE an internal loose connection, usually the fuse just blows because of self--generated heat

If the fuse was "out of spec" then nothing much should have happened, unless the circuit overloaded, so I guess that's possible.

My first "jump" is that there's a bad connection at the fuse connector, and or the circuit is severely overloaded.

Yes, the circuits were overloaded. Hence the statement:

(It was a 10Amp circuit, carrying a 20Amp load).

However, the fuses are supposed to blow on an overloaded circuit (That's what a short does - overload the circuit) to protect the wire/circuit/vehicle.
The HF fuses are not blowing (well, the guy paying the $400 repair bill can tell you that they certainly blow, just not as the manufacturer intended) and the fact that they're not popping means bad **** is taking place. In this case, about 6 feet of wire melted so bad it shorted with other wires in the harness and started overloading those circuits as well.

 

[RedFish]

I've mentioned this before. My brothers job is field failure analysis on anti lock brake processors and more for Bosch. Those components are powered by 30 amp fuses in any application. Through testing they have found little or no consistency fuses.
30 amp fuses will conduct 50+ amps for X milliseconds before opening.
Nature of the beast no matter who made it.

 

[jos51700]

I've mentioned this before. My brothers job is field failure analysis on anti lock brake processors and more for Bosch. Those components are powered by 30 amp fuses in any application. Through testing they have found little or no consistency fuses.
30 amp fuses will conduct 50+ amps for X milliseconds before opening.
Nature of the beast no matter who made it.

I agree, every fuse has a blow time, or time of overload prior to failure. Hence: Slow-blow fuses.

This isn't X milliseconds. This is months (well, the total elapsed time of circuit overload was technically infinity since the plastic had melted/burned away and the "fuse" was still going strong) of wire-harness melting and wires arcing.

"No matter who made it"...I disagree.

 

[69MOPE]

HF fuses were recalled. I remember reading about this a few years back.

 

[67Dart273]

HF fuses were recalled. I remember reading about this a few years back.

No kiddin'............

http://images.harborfreight.com/cpi/recalls/fuse_sets.html

 

[magnumdust]

why would one buy HF fuses??

I mean i like HF for specialty tools, but i'd never use them for something crucial.

 

[hemitheus]

why would one buy HF fuses??

I mean i like HF for specialty tools, but i'd never use them for something crucial.

eeeeeeeeyup

 

[Oklacarcollecto]

(It was a 10Amp circuit, but it had a 15 amp fuse, carrying a 20Amp load).

Would you not expect problems to start with by using a 15 amp fuse in a 10 amp circuit? Are you sure the owner didn't wrap a wire around a blown fuse? I would never use HF fuses anyway but this seems like it was likely the owners fault too.

The picture isn't clear enough for me to see the actual blades of the fuse and any connectors that may be present.

 

[jos51700]

Would you not expect problems to start with by using a 15 amp fuse in a 10 amp circuit? Are you sure the owner didn't wrap a wire around a blown fuse? I would never use HF fuses anyway but this seems like it was likely the owners fault too.

The picture isn't clear enough for me to see the actual blades of the fuse and any connectors that may be present.

Owner purchased the vehicle this way. The PO had NO right to be in there wiring anything.

Yes, I expect the wire to go too, no way around it, but with a 20 amp load on a 15 amp fuse and a dead short on the other circuit, they should have popped.

 

[/6 Matt]

Would you not expect problems to start with by using a 15 amp fuse in a 10 amp circuit? Are you sure the owner didn't wrap a wire around a blown fuse? I would never use HF fuses anyway but this seems like it was likely the owners fault too.

The picture isn't clear enough for me to see the actual blades of the fuse and any connectors that may be present.

Isn't the fuse supposed to be rated 33% above what the current will be and 33% under what the wiring will handle or something like that?

 

[craigerlitz]

I've mentioned this before. My brothers job is field failure analysis on anti lock brake processors and more for Bosch. Those components are powered by 30 amp fuses in any application. Through testing they have found little or no consistency fuses.
30 amp fuses will conduct 50+ amps for X milliseconds before opening.
Nature of the beast no matter who made it.

I agree, every fuse has a blow time, or time of overload prior to failure. Hence: Slow-blow fuses.

This isn't X milliseconds. This is months (well, the total elapsed time of circuit overload was technically infinity since the plastic had melted/burned away and the "fuse" was still going strong) of wire-harness melting and wires arcing.

"No matter who made it"...I disagree.

I am not trying to defend Harbor Freight either. I attached a part of a fuse spec of a UL listed fuse from Littelfuse, a well known fuse manufacturer. It shows that the max time that a fuse operating at 135% of the fuse rating could last until blowing is 600 seconds or 10 minutes. The 20 amp load on the 15 amp fuse would be 133% of the rating. If by chance the fuse took that long to blow along with the previous owner not using the proper sized fuse (10 amps), I could see this issue happening.

Craig