Well, yes they might clear, eventually. Then again, they may not.
I know you’re capable of doing the work so bear with me, I’ll do the exercise for the benefit of the new players. Let’s apply a fusible resistor to a typical Arduino battery powered project. Let’s say we have a 3.6v 4 Ah battery and assume the average current consumption is 100 milliamps. Here is the resistor datasheet:
https://www.yageo.com/upload/media/product/products/datasheet/lr/Yageo_LR_FKN_1.pdf
The first question to wrestle with is “how much power do I want to waste in my resistor”? Remember, it’s a resistor first, a fuse second. So, you say of course I want the lowest power loss possible so I’ll go with the lowest value I can buy, which is 0.1 ohms. Okay, that makes a nice shunt value to measure current consumption.
Ohms law says we’re only wasting 1 mW and dropping 10mV. That’s great you say and I agree. But, now as a fuse, what does it take to open it? The clearing time spec is “less than 60 seconds at 36X rated power”, noting this is power, not current. The lowest power part you can buy at DigiKey at 0.1 ohms is 2W.
That means you need 72 watts and up to 60 seconds to open the fuse. Since power is I^2R, we can see we need 26.8 amps for 60 seconds to open the fuse. Now, look at that from the batteries ability to deliver that kind of power. You’re asking for a reserve capacity of 1600 Ah from a 4 Ah battery. That’s 400X. What are chances the battery can do that? That looks like a complete fail to me.
Some will say what I picked was actually the worst case. Yes, it was and I can be annoying that way but I was making a point. What looks to be the best selection will not work in the most numerous and common applications. Okay, let’s check another value. Let’s say we can source 2 ohm 1/2 watt parts. What do we see there?
Now we have 200 mV of drop and 20mW of loss. Clearing time on 2 ohms does go down to 25X rated power with the same time of 60 seconds. So now we need 12.5 watts. Now it’s a more sane 2.5 amps for 60 seconds. That’s doable, right? Well, yes, it works but does it have any advantages?
No, it does not. Only disadvantages. First of all, it’s a resistor. It’s wasting power in battery application. It adds voltage drop, lowering the operation time of the processor. Worst of all, it’s a soldered onto the board solution. There are no quick change resistors in holders or sockets.
The application is to protect wires and a battery in a short circuit condition. That is an application for a fuse. A fuse can be easily installed inline in the wire with a readily available available fuse holder. You can buy the fuse and holder just about anywhere.
If someone still thinks a fusible resistor is a good idea, here’s the selection criteria: It must be selected carefully so it clears, albeit very slowly. You can only buy them at electronics distributors and you have to figure out some way of connecting it inline your my circuit. Oh, yeah, I could use a two pole terminal block. But, I’ve got to make sure I mount it away from my wires because it could melt the insulation as it heats up to get the point it opens.
Yup. Sure. Sounds like something I’ll never do. My entire point here is why select a special order part when the available everywhere stuff is the better choice? Why use a resistor when a fuse will do?
BTW, the primary application for fusible resistors is in AC mains side of switchmode power supplies where a failure can cause standard resistors to explode and or turn into fireballs themselves or preventing other components in the circuit from ignition. Any place where you need a resistor and have very high potential energy that can be released and cause secondary damage that could result explosive forces and or ignition.
But, hey, whatever. Everyone is free to make their own decisions guided by random people on the Internet typing random stuff about topics that they may or may not have even a cursory understanding of but they certainly have an opinion which they share as though it was based on solid, rigorous scientific research. It is nothing short of amazing to watch some of these threads give life to some of the worst ideas ever that achieve a level of validation only through the power of consensus.
Attempting to use something that is not designed for the purpose makes no sense whatsoever.