"Groovy" flat fuses VS non-groovy

[Eskimo007]

I recently needed to replace a 40amp DC flat fuse between my RV battery and inverter, and had the hardest time trying to insert the spare fuse that the original owner had provided. Upon (very) close inspection, I noticed that the replacement fuse although the exact same size and appearance as the burnt out one had some grooves on each side, whereas my replacement did not. Needless to say, trying to force the replacement in the holder brought no joy.


Does anyone know what the difference is between the 2 types? I'm thinking maybe slo-blow or not? Looking at the transparent casing of the fuses, I can see the inside is different.

[Eskimo007]

So you notice those big grooves on the left one and not the right... I stopped by the local NAPA parts dealer to ask, he had some with grooves and some without but didn't know the difference. I also messaged Littelfuse, maybe they will enlighten us. "That's what I like about standards, there are so many of them!"

[NRALIFR]

Correction, I didn’t recognize the Onedrive link you posted. I actually can see the image if I copy paste it into a browser window. Here it is.



:):)

[NRALIFR]

No, the image location you posted is on your cloud storage site, and it needs to be on a public image hosting site. I don’t use Onedrive, but I suspect it doesn’t allow that type of linking.

If you can email it to me I’ll post it for you. I can also help you figure out how to use the IMGUR link I posted.

:):)

[Eskimo007]

Cant take a pic right now, the RV it's in is out in New Brunswick. I'll forage around my folders, I might have taken one. Can you see the picture from the Onedrive link I posted? Esp the one looking top-down?

[NRALIFR]

Jacques, can you take a picture of the location where that fuse is supposed to plug in?

If you can email me that picture, and the one you just tried to post, I’ll post them both for you.

I’ll PM you my email address.

:):)

[Eskimo007]

I think the grooves are much more obvious if you look at this picture, the fuse on the left, way-non-trivial grooves which no amount of coaxing even with pliers will bring any joy. 1drv.ms/u/s!AlUCXH-477GAipJuc1QtvC3nggC3QQ?e=AfB3RO

[ktmrfs]

NRALIFR wrote:

Eskimo007 wrote:
It's a 40A like the Maxi. Will try to add a picture to my post that clearly shows the grooves above the blades on both sides.




(cant figure out how to post pictures, says link removed)
1drv.ms/u/s!AlUCXH-477GAipJtv8NIRuvampPKpg?e=bT3pNF


1drv.ms/u/s!AlUCXH-477GAipJuc1QtvC3nggC3QQ?e=AfB3RO

I think he’s talking about the areas I’ve circled, guys.

The replacement fuse doesn’t appear to have those same “grooves”, and if the device the fuse is for has a fuse socket shaped to accommodate those grooves, one without the grooves ain’t goin in!

:):)

OK I take back my comments about the groves on the blades where it contacts the socket.

there are lots of mfg of these fuses anymore, and some are of questionable quality. IIRC harbor freight had to recall a bunch for safety issues.

first thing i would do is look at a bussman or littlefuse brand and see what they look like and if they fit.

[NRALIFR]

Eskimo007 wrote:
It's a 40A like the Maxi. Will try to add a picture to my post that clearly shows the grooves above the blades on both sides.




(cant figure out how to post pictures, says link removed)
1drv.ms/u/s!AlUCXH-477GAipJtv8NIRuvampPKpg?e=bT3pNF


1drv.ms/u/s!AlUCXH-477GAipJuc1QtvC3nggC3QQ?e=AfB3RO

I think he’s talking about the areas I’ve circled, guys.

The replacement fuse doesn’t appear to have those same “grooves”, and if the device the fuse is for has a fuse socket shaped to accommodate those grooves, one without the grooves ain’t goin in!

:):)

[D_E_Bishop]

I'm with DrewE's first sentence. Those groves are not significant electricity wise. Just try a little harder to insert the new fuse.

It ain't rocket science.

I am adding to my original post as I was called away without being able to finish.

I have enough life experience(81years)and in the electrical field for 51 years, that I feel safe saying that the really odd ideas about shape of the blades and the plastic is just grasping at some really far away straws.

If it won't fit at all and there are absolutely no manufacturer marks on the original fuse, the solution is to replace the fuse holder or maybe contact the vehicle mfg or the mfg of the part and ask it the fuse is special.

Asking here has not accomplished anything concrete and doesn't seem likely after reading the response that follows mine just a waste of time.

[ktmrfs]

those "groves" in the blades are from the female receptical the fuses goes into. with 40A you MUST have very low contact resistance with the fuse, and the ONLY good contact surface is through the groves and the hopefully high contact force to the back of the receptical.

those Maxi fuses take a lot of force to install.

[Fisherman]

I'm going with what DrewE said, most likely makes for a tight positive contact.

[DrewE]

I don't think the grooves signify anything, nor ought they interfere with the fuse insertion. I think they're just an artefact of the way the prongs are manufactured on the one fuse (they appear to be laminated out of a couple thicknesses of metal on the one, vs. cut from a single thicker piece on the other). I might be wrong, of course, but it seems quite unlikely to me that they are significant.

Perhaps you simply weren't applying enough force to get the fuse into the socket? Sometimes these sorts of things can be really tight and need more persuasion than one would generally expect.

[NRALIFR]

I don’t think I’ve ever noted that difference before, but I see what you mean now. If the device the fuse is for uses those grooves as a “key”, you can only use that style of fuse.

Most of the maxi fuses you can order on Amazon (that have decent pictures) appear to have the grooves, but that doesn’t necessarily mean that’s what you’re going to get.

I guess I would just take your old fuse to an auto parts store and buy one that looks the same.

:):)

[opnspaces]

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