Can someone test the t class fuses? For littlefuse (blue sea) and south bend?

[gotbeans]

I and many other people are interested in the south bend components fuses but there's not much info and zero tests on it
I was thinking of a way to test these fuses. I think putting some cheap lead acid batteries in series to 48 volt and putting a higher rated fuse or multiple in series and then the lesser rated fuse to be tested would be easy enough.
At lower amps we have bench power supplies but at higher we don't really.

Also interested in seeing the littlefuse "blue sea" being tested.

There are several other people that seem like they'd be interested in doing this. It'd not be the most expensive video.
Seems like a test for the youtuber styropyro but he's not here & doesn't really test equipment either.

This appears to be the only good test done with "higher" amp fuses, but it doesn't have t class ones:
here we see that the victron fuses are terrible and pretty dangerous vs their ratings. Which makes me curious about the other ones.

@KITROBASKIN

T-fuse. Are they always required?

I see T-fuses being mentioned in other threads and even in my own listed below. I understand a T-fuse is a quick acting fuse inside a sand filled cartridge and that it prevents arcing after being blown. I don't understand why I would need a T-fuse for a 12V DC system with 100A output LFP...

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@eemarty

Class T vs ANL fuse

you mean the cigarettes with ‘micronite’ asbestos filters? Ah Canadianisms... I quit smoking 20 years ago, but I must confess I do like a certain brands of American cigarettes. Unless you have some Turkish cigarettes... and Cuban Cigars. And Northeastern Yankee wiskeys.... ( proper wiskey...

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@Skypower

400A 160VDC T-Class Fuse Holder Melted

Make sure you write a review and include your pictures. Did that and got a reply from seller offering full refund. We'll see if they come through with that.

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EG4-Lifepower4 Battery Bank Fuse Size?

Hello All! I have four EG4-Lifepower4 48v 100A batteries coming to me soon and I would love some advice on fuse sizing. I have done some research already and have found some are saying I will need a fuse, some say don't bother. If I don't need a fuse, great, I'll skip this step! But if I do, I...

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@undercrust

MRBF Fuse brands (Canada edition)

Looking for the collective wisdom of the forum here. I ordered both the Blue Sea MRBF fuse and block, as well as the South Bend MRBF fuse and block, since everyone seems to know Blue Sea's reputation, but I couldn't find an opinion on South Bend. From what I could find online, I believe South...

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Sorry to tag anyone that isn't interested, but you all seem pretty interested in this subject and there has never been a conclusion. I have read a few years worth of threads and every mention of it.

 

[12VoltInstalls]

At ~$40/each and much more there’s a bit of a price barrier to just blow fuses without sponsorship. No matter if I’m in feast or famine mode I don’t toss wads of $20bills in the campfire just to watch them burn.

 

[gotbeans]

At ~$40/each and much more there’s a bit of a price barrier to just blow fuses without sponsorship. No matter if I’m in feast or famine mode I don’t toss wads of $20bills in the campfire just to watch them burn.

probably a low-average video for testing equipment. Some videos cost thousands, but depends on how many views someone is expecting.
I'd easily pitch into a pool to have this tested. I think many others would too.

 

[12VoltInstalls]

probably a low-average video for testing equipment

I buy/bought UL listed Class T fuses.
They’ve already passed muster imho

 

[gotbeans]

I buy/bought UL listed Class T fuses.
They’ve already passed muster imho

victron ones have like 4 pages of certificates and ratings
They blow 50 amps higher than rated.
Pretty bad

 

[Mattb4]

I got to test a 125a ANL fuse a couple of months back. Being distracted I was using one of my 3kW AIO's to use excess solar to heat water in the hot water tank. This pulls 2000w. While doing this I lost track and decided I was going to grab a lunch. I preceded to nuke a hot dog in the 1000w microwave that pulls 1700w. 2000w plus 1700w equals 3700w/25vDC=148a or above 125a fuse I had to my battery. It went pop very nicely and the AIO transferred to grid with a loss of battery fault.

In terms of circuit protection I would say it did exactly what it was supposed to do.

 

[DIYrich]

I got to test a 125a ANL fuse a couple of months back. Being distracted I was using one of my 3kW AIO's to use excess solar to heat water in the hot water tank. This pulls 2000w. While doing this I lost track and decided I was going to grab a lunch. I preceded to nuke a hot dog in the 1000w microwave that pulls 1700w. 2000w plus 1700w equals 3700w/25vDC=148a or above 125a fuse I had to my battery. It went pop very nicely and the AIO transferred to grid with a loss of battery fault.

In terms of circuit protection I would say it did exactly what it was supposed to do.

I belive the reason for Class T is if you have a short that draws thousands of amps. Can the ANL or Southbend break the circuit.

 

[12VoltInstalls]

In terms of circuit protection I would say it did exactly what it was supposed to do

Yup. Even though it was an OHSE and not an actual fault. (Operator Head Soace Error)
I used the Class T 125A fuses on the 12V/100A BMS batteries because of the minute risk of sustaining an arc from LiFePo4 discharge in an actual fault. Shared power potential is 300A to the busbar but each 1AWG battery cable circuit is protected and “something bad” downstream would (should?) get shut down faster than a fire can start.
Like an insurance policy that prevents a loss versus a real insurance policy that costs more annually than the fuses but allows a payout only after you lose everything.

Not criticizing your ANL usage, just saying what I did.

 

[DIYrich]

As a USA company, the likelihood of South Bend using cheap knockoffs is low. They would be sued out of business by now.

South Bend Components - Quality OEM Components Manufacturer

At South Bend Components we supply a broad array of high-quality components for the leading original equipment manufacturers ("OEMs") of leisure marine and recreational vehicles, and the related aftermarkets of those industries.

www.southbendcomponents.com

 

[Mattb4]

I belive the reason for Class T is if you have a short that draws thousands of amps. Can the ANL or Southbend break the circuit.

It is a good question. Class T is definitely a good choice for the large 48vDc setups. A dead short I suppose is a remote possibility though I imagine the 160a MCCB I have in the circuit ought to take care of it.

There is also the fuse in the AIO and the BMS amp limit.

BTW, If my memory of the incident is any good (at my age of 64 it is not always) the fuse held for about 10seconds of the microwave operating.

 

[Hedges]

victron ones have like 4 pages of certificates and ratings
They blow 50 amps higher than rated.
Pretty bad

Fuses and breakers have a wide range of trip/blow current. Depends on time and ambient temperature + cooling effects of installation.
I think magnetic-hydraulic breakers should be more tightly controlled.
But thermal protection responding to ambient temperature isn't entirely a bad thing.

These curves show a single line per fuse amp rating, but it is really a range from "guaranteed not to blow" to "guaranteed to blow"

https://www.eaton.com/content/dam/eaton/products/electrical-circuit-protection/fuses/bussmann-series-branch-circuit-fuses/class-t/bus-ele-ds-1025-jjn.pdf

DC testing is more difficult, hard to set desired current. Difference in performance is how arc is extinguished.
Midnight wrote a paper about testing polarized breakers in wrong orientation. They used a string of car batteries.

AC testing, easy to dial in desired current, at least for testing at reduced voltage. This won't be representative of arc extinguishing, but makes time/current easy.
What I did was I connected a transformer primary in series with electric radiator(s), and paralleled a Variac with another electric radiator. That lets me switch heating elements and dial in exactly the current I want.
Secondary has stepped down voltage, stepped up current. You can cascade another transformer for another multiple of current.

Testing Magnetic-Hydraulic circuit breakers

I've built myself a circuit breaker tester. I assembled three transformers into a 3-phase wye auto-transformer, and by means of a breaker and cord/plug it can be repurposed into a current multiplier. A breaker connects X1 to H2 and H3, providing 4.7x current boost on X2 paralleled with X3...

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(The breaker curves shown there do have min/max)

I had three toroids I wired together, slow-tripped 100A breakers and fast-tripped 20A. Would need more watts of heater to get 1000A+ and fast-trip 200A breaker.

Using non-UL insulation

A while back I bragged about creative use of heater hose as tough, large size insulation for electrical terminals: https://diysolarforum.com/threads/fire-never-cover-lifepo4-with-wood.19373/page-12#post-238207 It seemed like a good idea at the time. More recently, I was wiring up...

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It is a good question. Class T is definitely a good choice for the large 48vDc setups. A dead short I suppose is a remote possibility though I imagine the 150a MCCB I have in the circuit ought to take care of it.

What are it's AIC ratings at 60V or above?

 

[Q-Dog]

The fuses should be tested in their correct fuse holders. Yes, it matters. Oversizing the cables can also make them take longer to blow. Follow the manufacturers directions if they suggest cable sizes.

 

[Mattb4]

...




What are it's AIC ratings at 60V or above?

Here is their spec listing for this class of breakers.

 

[Hedges]

I would say undersizing cables and bad connections makes fuses blow faster.
The cable will serve as a heatsink for moderate overloads. High current where blowing is expected in seconds to a minute, shouldn't matter as much with a large thermal gradient along fuse element.

Wires get a hit of thermal stress when OCP blows. I've read the ampacity is designed for about 100 such events. A 50% overload takes maybe 15 minutes, and that current is 2x temperature rise (given enough time). For 14awg through 10 awg, allowed OCP is significantly lower than ampacity. These circuits are often used for multiple outlets, where homeowner is free to overload them and trip repeatedly. The higher ampacity should protect against damage.

 

[rhino]

As @Hedges mentioned you can't simply test fuses amp to amp without indicating the trip curve at least. It would be a bad design if you put in a fast blow fuse like in that video that tripped at exactly 100A. It would provide no ability for a surge like a motor to turn on.

 

[Hedges]

Here is their spec listing for this class of breakers.

Not sure from the table if 25kA to 50kA is for multiple poles in parallel.
I often see voltage vs. poles in series.

Impulse 8000V

Are these ratings for AC, or for DC? At what voltage?
If the 25kA rating is for DC at your battery voltage, that's great.

 

[Mattb4]

Not sure from the table if 25kA to 50kA is for multiple poles in parallel.
I often see voltage vs. poles in series.

Impulse 8000V

Are these ratings for AC, or for DC? At what voltage?
If the 25kA rating is for DC at your battery voltage, that's great.

It is a DC breaker so I would imagine the ratings are DC based. As to the poles I would guess parallel would give the double rating factor. In series they should not gain anything.

I missed in the screen shot the voltage part of the specs. Here it is.

 

[Hedges]

25k AIC at 250VDC is pretty good. Maybe even higher at your battery voltage although not documented.
That should cover a modest size lithium bank. I would use one pole per string if multiple batteries.

 

[time2roll]

victron ones have like 4 pages of certificates and ratings
They blow 50 amps higher than rated.
Pretty bad

Class T will pass 200% rating for close to a minute according to the Blue Sea graph.
I would keep these a bit tight as they are short circuit protection more than for slight overload conditions.

 

[gotbeans]

Class T will pass 200% rating for close to a minute according to the Blue Sea graph.
I would keep these a bit tight as they are short circuit protection more than for slight overload conditions.

https://www.littelfuse.com/media?resourcetype=datasheets&itemid=2925cc6d-2278-44e0-8fdd-106f087f707e&filename=jlls-fuse-datasheet

What's their rating then if all of them pop at double the amps their number says?
& Yea I typically use a fuse for short circuit and breaker for overcurrent

It is a DC breaker so I would imagine the ratings are DC based. As to the poles I would guess parallel would give the double rating factor. In series they should not gain anything.

I missed in the screen shot the voltage part of the specs. Here it is.

what is this mystery breaker?