Automotive Fuse Comparison with a Milli-Ohm Meter

John Educator Ogden, Utah Posted   Latest  

If you thought all automotive fuses were of the same quality, think again! We compare four fuse brands using a Hioki RM3548 milli-ohm meter, the results are unbelievable! See the video and the attached file for the specifications and results. I was very impressed with the Littelfuse and Bussman fuses; not at all impresses with the other "Brands".

After shooting the video I learned that Littelfuse makes their own fuses and supplies fuses to 80% of the world's automotive market. I was told that Bussman no longer makes their own automotive fuses, they are supplied by two other reputable fuse makers; one in Japan (PEC, the fuse supplier for Toyota and Honda) and one in Taiwan (Jenn Feng). There are a lot of good product data sheets and fuse educational information sheets on those websites. I have a crazy schedule, so I may not be able to reply to your comments or questions very quickly. youtu​.​be/nELwmfAOz_I

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Michael Mobile Technician
Clinton, Utah
Michael
 

Hi John, Very good demonstration. I am very curious if you could measure at what current the off-brand fuses blow. Thank you for sharing.

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John Educator
Ogden, Utah
John
 

Thank you! I plan on doing that, but I need to obtain a few more pieces of equipment to accurate control the current. There are specifications of percentage of over-current verses time. I want to try that and then use the frame rate of the camera as the timer.

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Bruce Technician
Spring Hill, Tennessee
Bruce
 

I did a test on some generic fuses. They were performance tool from the parts store, the numbers were not white. Put a 5 amp fuse with a current loop in place of a cooling fan fuse. It peaked over 50 amps and ran the cooling fan. I don't remember what the continuous amperage was. Put in a Bussman 5 amp fuse and it blew at 11 amps when I turned the fan on, cooling fan didn't move.

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Michael Mobile Technician
Clinton, Utah
Michael
 

Bruce, Cool idea for testing.

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James Owner/Technician
Pike, Pennsylvania
James
 

Great info on something most, including myself, might not of ever considered. I will think better next time I restock my fuse bin. Thank you!

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Bruce Technician
Spring Hill, Tennessee
Bruce
 

If you have any generic fuses, I would throw them away. If a 5 amp fuse will run a cooling fan. Will it blow when it needs to? Will a generic 30 amp fuse blow at all?

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Martin Instructor
Burnaby, British Columbia
Martin
 

Great work as usual John. I was already aware of the GM bulletin about the Harbor freight Storehouse brand fuses from long ago and the fact that all fuses are not necessarily "engineered" to the same level. However, I've never bothered or had the time to go to the extent of testing, supported with measurements that you did here. Thank you for this. I do advise my GM ASEP students to beware of

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John Educator
Ogden, Utah
John
 

Thank you Martin. I have seen the same thing just plugging in a fuse in an underhand fuse block with the ignition turned on. It never occurred to me that it was my fuse quality. Thanks for the story and examples.

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Robby Mobile Technician
New Market, Alabama
Robby
 

Hi John, Great demonstration! Thanks for posting this. I almost caught a truck on fire one time by using one of those cheap fuses. The fuse for the DLC was blown, so I stuck in one of those fuses. That circuit was shorted to ground and it melted the plastic body of the fuse instead of "blowing" the fuse. Another issue with a cheap fuse is the size of the blades. On the cheap fuses I've seen…

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