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

[rhino]

I've got some name brand (think it is Littlefuse) class T holders, and they have cooling fins.

https://www.digikey.com/en/products/detail/littelfuse-inc/LFT304001CS/2670456

 

[Hedges]

Yes, like that. May have only been 2 fins.
Less expensive on eBay.

I was going to add 400A class T coordinated with 200A main breaker for catastrophic shorts, but decided box volume too tight.
So they will go on battery.

 

[12VoltInstalls]

if your system is 12V

The class T dropped about 1% and also got surprisingly hot

Interesting.
Currently I’ve only got 1800W of panels running and none of my ClassT get warm.
But 1.8kW is fairly small.

 

[SupraSPL]

Interesting.
Currently I’ve only got 1800W of panels running and none of my ClassT get warm.
But 1.8kW is fairly small.

The heat will depend only on the current. In my case it was about 200 amps. It may have been as much as 250A but I'm going from memory.

 

[gotbeans]

Do you have any example of Bussman, Littlefuse, other top tier name fuses failing to meet their specifications?

Nope, this is a thread to test them. You want that data, agree to the thread

The heat will depend only on the current. In my case it was about 200 amps. It may have been as much as 250A but I'm going from memory.

Also ambient and also if you have some sort of wind flow going on.
My ambient for some fuses ranges between 30 and 100 degrees which I only assume pretty massive for their ratings

 

[Skypower]

hilarious coincidence he's doing testing of them

meanwhile half the people in this thread:



yea I got one of those nanque too, any breaker from any company can die at any time but the massive amount of testing is always reassuring.

I have to admit that immediately after watching this Louis Rossmann video I ordered the brand that tested best. I recently installed two new fuses blocks in a boat to replace the rats nest of inline fuses. The blade fuses were a collection of cheap assortments from Amazon and auto parts stores over the years and some looked kinda chinsy. There so many in the kit that I can afford to sacrifice a few in each range to verify performance. I’ve got a large selection of 5X20mm glass tube fuses I’ll doom while I’m at it. I’m going to try to use my internal resistance meter to see if there’s any correlation to blow current = non destructive testing = recategorizing. Sorry not going to blow $40 a pop on T class fuses. I do have a 5KVA variac and two turn microwave oven transformer so current isn’t the issue. One thing of curiosity, a littelfuse 300 amp fast blow has higher resistance and more voltage drop than a South Bend 250 amp fast blow when subjected to a 75 amp load. No much, a few milivolts.

 

[Hedges]

I’m going to try to use my internal resistance meter to see if there’s any correlation to blow current = non destructive testing = recategorizing. Sorry not going to blow $40 a pop on T class fuses.

If the fuses increase in resistance as they get hot, positive TCR, you should be able to find different curves for them without destructive testing. I'm sure that's easier to accomplish by first logging the curve for destructive testing. But it could be something like hitting with increasing pulses, using 4-wire resistance to determine element temperature, wait until cooled to same point for each step. Categorize according to current/time required for something like 50% resistance increase.

I did a simple test of automotive fuses to make sure they were marked correctly. The manufacturers did choose to use same element for two ratings, close enough to meet some tolerance spec:

Testing automotive fuses

After watching a video (sorry can’t find it now) showing resistance testing of cheap fuses and name-brand ones, I decided I’d better test the ones I’ve put in our cars. In the video, it was said that previously Harbor Freight sold fuses, but later recalled them and didn’t carry anymore. Fuses...

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