Use a fuse - and wear safety glasses... This could have been very bad.

mrzed001 said:

Maybe you should focus on that video too ... because the fuse did what it supposed to do.
Did not catch fire, no plasma explosion ... nothing.
It did work as it should.


No. It is a JLLN 200 Class T fuse and that has melamine body.
I more like the NT - NH fuses. Ceramic body, bigger, cheaper, better. But that Class T is fine too.



In that case the fuse is too weak, so the installer did not know what he is doing.
The fuse has an interrupt capacity. And it has to interrupt bellow that. Engineers designed and then quality control tested it.
Also it is always wise to oversize V and interrupt capacity ... only Amps stay.


Until you hit it with a hammer or drag it in the road ... that fuse will be fine.
And waaaay better than ANL or MEGA fuse in any fuseholder


The sand is inside the fuse body. Pressed. No need for any fuse holder for it to do its work.



Or maybe you do not want to hear any other arguments than yours.

What are you debating about?
Did the fuse work? Yes.
Without holder? Yes.
Better in a holder? Off course. But even without a holder light years better than anything most people use here.

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I am trying to understand your mission on this forum.

a member asked what benefit or harm COULD happen without a holder… I gave a admittedly worst case scenario… one I have seen a great many times…

you come on and claim the holder’s one and only purpose is to mount the fuse.

Seriously… why are you arguing about these points?

Sure, the fuse in the video didn’t fail or melt down or anything of the sort… it was an EXTREMELY brief short. It could have been far worse.

HRTKD said:

The incident in the video of the original post got me to thinking about my Blue Sea switch. Yep, the 3/8" studs on the back are exposed. Even a piece of electrical tape over the studs would be better than nothing. A cap would be nice, but it might stick out too far, which would make the switch difficult to mount.

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I have a can of this onboard
Seems to be good stuff
Comes in black and red

Supervstech said:

I am trying to understand your mission on this forum.

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To teach and to combat inaccuracies.

I am also translating my summary doc (to post or pdf ... donno yet) where I show (almost) all inverter usage possibilities like grid-tie (central inverter, microinverter, with and without limiter, Balkonkraftwerk), off-grid, off-grid with grid support (with inner limiter and with double conversion), hybrid systems like DC coupled, AC coupled (with auto transfer switch), single unit hybrid, grid-tie + UPS hybrid ... and all its benefits pros and cons with connection diagrams.
To have a common ground when someone writes grid-tie or hybrid.
To show users the possibilities to expand there system (even DIY in many scenario).
First I made this a hybrid study ... because every other day a different user came and asked that : "I have solar in my roof (GT) and still sitting in a dark in a blackout" (GT is used a lot here, OG is almost not known)

And what is your agenda?

Supervstech said:

a member asked what benefit or harm COULD happen without a holder… I gave a admittedly worst case scenario… one I have seen a great many times…

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I am all about safety. But you misunderstanding the FUNCTION of the fuseholder.

Like you could say that Do not use extension cables ... because in a worst case they can go up in flames.
Yes, they can, seen it. And we still use them because 99.99999% of the time they don't.

Supervstech said:

you come on and claim the holder’s one and only purpose is to mount the fuse.

Seriously… why are you arguing about these points?

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Because it is the fuseholder sole purpose. And to make easier to replace the fuse. There are cable fuses where you have to replace a piece of the cable with the fuse. It was a user made variant of that.

Most fuse holders are open. Do not have any plexy on the user side (sometimes the cabinet has that the fuseholder is placed but that is only for touch protection).
Really only 2 contactor. And, I showed you them, put in pics.
Have a backplate ... only to be a single unit. Like in first pic only a little backplate. And that is for a strong 160-400A NH1 fuse I think !

Supervstech said:

Sure, the fuse in the video didn’t fail or melt down or anything of the sort… it was an EXTREMELY brief short. It could have been far worse.

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It was a brief short BECAUSE the fuse blow.

See, here are some NH1 fuses I use too. This is a solar power plant. Also there is a dissection in the end.

personally I’ve never seen a T-class fuse blow before..


this person shared their oops

personally, I think it’s inadvisable to leave out the holder because stresses from big cable could warp or compromise the thin shell of the T-class fuse.

not doubting that molten slag can come out, perhaps it’s something people with 25kWh+ banks and stuff need to worry about

curiouscarbon said:

personally I’ve never seen a T-class fuse blow before..

this person shared their oops

personally, I think it’s inadvisable to leave out the holder because stresses from big cable could warp or compromise the thin shell of the T-class fuse.

not doubting that molten slag can come out, perhaps it’s something people with 25kWh+ banks and stuff need to worry about

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If there is a mechanical stress on the fuse then yes a holder is absolutely needed.
If not then not. Or you can even DIY one, it is just a plastic and 2-4 screws. Have seen worst.
That is not a thin shell. At least 2-3 mm

Teaching moment ?
You know why there is sand in it? Not only because sand directly blocks the arch.
The main problem with sandless fuses (like a glass fuse) are that the melted metal can evaporate in a blow and make a plating in the glass inner.
And that plating is conductive so again an arch happens. Many times sandless fuses (even it should have sand in it like faulty or cheap clone) explode because of it. So the sand catches the blown metal.

If you watch the dissection video you can see the 4 connection points inside the fuse. There are weakened, the soft points the connection needs to break.
And the connecting parts (conductors) all 4 are intact.
So ... this fuse easily blocked the short circuit with little stress. If it were a high stress to the fuse then the connecting parts were melted.
(and now I am gone to holiday )

Edited a few posts that were getting out of line, please be respectful of your fellow members.
If I missed anything you thought particularly offensive please click the report button on it so it can be reviewed.

svetz said:

Edited a few posts that were getting out of line, please be respectful of your fellow members.
If I missed anything you thought particularly offensive please click the report button on it so it can be reviewed.

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Thank you for the correction, perfect. Was a bit on hurry. Sorry

I hope she still has that fuse. It's in perfect condition. If you look at 36:50, the shorted terminal is the same one her battery wire is on, so she had a dead short with no protection at all. Reflexes to pull the thing off are all that saved her.

TorC said:

I hope she still has that fuse. It's in perfect condition. If you look at 36:50, the shorted terminal is the same one her battery wire is on, so she had a dead short with no protection at all. Reflexes to pull the thing off are all that saved her.

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Looks to me like a dead short from positive to negative. Her positive terminal is at the other side of the box, red wire with fuse in the middle, and then the switch - that's all main positive. Then shorting to the main negative pole on the battery (right side of the cell with all the blue wires coming out). I believe she also confirmed the fuse to be dead in a later video.

Oh, whoops. Looks like I misunderstood where the fuse was. Hadn't paid proper attention to the bulge in the red cable and only noticed the device in her hand.

TorC said:

Oh, whoops. Looks like I misunderstood where the fuse was. Hadn't paid proper attention to the bulge in the red cable and only noticed the device in her hand.

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No, that was just a switch she was holding.

By the way, welcome to the forum!

"It won't happen to me" is often true.... but when it isn't you will be glad you played the long game.

It’s because of her video (I saw it a while back) that I made sure to buy a spare fuse for my class T holder.

If you'd just looked around, you would probably have found you had spare class T fuses already.

Hedges said:

If you'd just looked around, you would probably have found you had spare class T fuses already.

View attachment 79626

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Reminds me of the Lucas Electric Guide for Fuse Replacement: https://mgb1967.com/lucas-guide-to-fuse-replacement/lucas-fuse-replacement-chart/

svsagres said:

Reminds me of the Lucas Electric Guide for Fuse Replacement: https://mgb1967.com/lucas-guide-to-fuse-replacement/lucas-fuse-replacement-chart/

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Please be easy on this adventurous individual. This can happen to anybody.
Learning curves are more common for we who learn the hard way. Thanks

queenpictoria said:

Please be easy on this adventurous individual. This can happen to anybody.
Learning curves are more common for we who learn the hard way. Thanks

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I've actually really enjoyed her videos, and learned a lot from them. Some things I agree with, others less so, but it's been excellent to see someone actually working with and experimenting with the kit that I will soon be playing with.

Edit: and she has good taste in scotch.

queenpictoria said:

Please be easy on this adventurous individual. This can happen to anybody.
Learning curves are more common for we who learn the hard way. Thanks

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She can handle it, or she wouldn't have left it in the video. Pretty sure she has a good sense of humor as well.

svsagres said:

and she has good taste in scotch.

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Agreed!

upnorthandpersonal said:

She can handle it, or she wouldn't have left it in the video. Pretty sure she has a good sense of humor as well.



Agreed!

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She looks a little Irish. After a few of those youll get a black eye, then the cops come...

HRTKD said:

The incident in the video of the original post got me to thinking about my Blue Sea switch. Yep, the 3/8" studs on the back are exposed. Even a piece of electrical tape over the studs would be better than nothing. A cap would be nice, but it might stick out too far, which would make the switch difficult to mount.

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I have one of those I put inline on a charger cable... Posts/bolts are stupid long Cut the bolts on back as short as possible, used the enclosure it came with, wrapped the whole thing with tape anyway. The bolts are copper.

I've just viewed some of her newer videos --looks like she hasn't learned a thing about building batteries safely -- Studs and Terminals all exposed under a workbench full of metal tools --makes me cringe just looking at that -- not to mention always having some kind of drink right there ready to be knocked over -- nothing like a little Scotch to cloud the mind when fooling with 20000 + amps of battery -- JMTC

BigGun said:

I've just viewed some of her newer videos --looks like she hasn't learned a thing about building batteries safely -- Studs and Terminals all exposed under a workbench full of metal tools --makes me cringe just looking at that -- not to mention always having some kind of drink right there ready to be knocked over -- nothing like a little Scotch to cloud the mind when fooling with 20000 + amps of battery -- JMTC

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Seriously if its not high voltage just keep a few fire extinguishers handy, be ready to run and have your phone in your pocket to call 911. Doesnt hurt to keep welding gloves nearby either.
When Ive had a number of surplus laptop battery packs to tear apart, and anyone whose done that knows how common mishaps can be, I usually keep a large soaking wet towel and a bucket of water nearby. The towel keeps the flames from getting out of hand so you can just rip the shorting cell off the assembly. Worst case you just dunk the whole thing in the bucket.
Ruins the pack but saves the house.
Mishaps do not turn into emergencies if you expect them and plan accordingly.
Ive got to be the sloppiest worker when it comes to paint, jb weld, liquid nails, any other adhesive, fiberglas resin ... I dont start the job without having my clean up materials ready first cuz Im gonna have epoxy all over my hands or Im gonna kick over that one gallon can of oil based kilz. If Im ready for it nobody has to know later.

I've shorted a VTC6 in a 60v pack before -- That is nothing compared to when I shorted my wedding band on some CALB cells -- in a nano second it was glowing red on my finger --- From that day on my tools are wrapped and I cover the terminals I'm not fooling with (Kapton Tape is Cheap)
As far as taking apart 18650 packs --- Outside is the only way to go

BigGun said:

A little Tape over the terminals goes a long way --- I learned my lesson with my wedding band

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when I was a apprentice as a electrician - it was drilled into me - never to wear a ring to work.

we had some high voltage rooms, where we didn't even where allowed to wear jeans with the metal rivets and buttons. Head to wear special clothing's and shoes with no metal whatsoever.