Types of Fuses, Fuseholders Used in DIY & Household

Thomas Edison has patent on fuse. Fuse provides overcurrent protection to a circuit using basic theory. Thomas Edison never discovered incandescent bulb but he discovered the Edison screw mount and modified filament. Thomas Edison has not discovered fuse too. Who discovered fuse that is not known, he added a standard and Louis Breguet recommended such thing in mid 1850. There is another similar thing named circuit breaker. Circuit breakers commonly used now in apartments, households which essentially looks like a switch and automatically cuts off the power supply to circuit upon short circuit, overload. Thomas Edison mentioned circuit breaker too in his patents. There are similar things like fuse named thermal cutoff, resettable fuse etc. Resettable fuses are not the thing one may imagine from name – it is not the type with fuse wire. Thermal cutoffs are commonly found at the bottom of household things which has motors like food processor, washing machine, mixer grinder – a red coloured plastic rod becomes elongated upon overload. Cars also have fuses. Obviously anything on this earth related to electrical can be divided in to :

1. For AC supply
2. For DC supply

And :

1. One time use
2. Resettable

We commonly see “one time use” fuse, there is no actual with no AC, DC matter – they are simply a wire which follows the I square T equation and gets blown away upon crossing a given load. There are complicated fuses in electronics and electrical like used inside the refrigerators.  In this article we will only discuss about the types of fuses, fuseholders used in DIY & household electrical and electronics. In other words, we will not discuss about circuit breaker, thermal cutoff, resettable fuse, automotive fuses and rarely which types someone unlikely to face for DIY and household – we are towards the fuses which follows I square T equation. There are lot of complicated standards and confusions with fuses in industrial usage. Fuse, fuse holder, fuse wire have these parameters written –

1. Ampere rating
2. Voltage rating
3. Time-current characteristic (fuse speed)
4. Interrupting rating (Breaking capacity)
5. Approvals,  standards (if any)

Types of Fuses, Fuseholders Used in DIY & Household

After our so much filtering of types, remaining is ceramic fuses which are officially named semi-enclosed rewirable fuse (SERF). They are usually made of ceramic with metal contacts and uses fuse wire. Obviously they are cheap at long run, convenient, heavy duty. But their form factor prevents to use them inside smaller compact panels where typically cartridge fuses are used. Cartridge fuses typically a fuse wire enclosed inside a glass/plastic tube. Axial fuses are type of cartridge fuses. There are other types of fuses like SMD fuses, axial fuses, thermal Fuses, HRC fuse etc.

Filtering more, for DIY works, you need to know only about the cartridge fuses, axial fuses and their fuseholders. Fuseholders for cartridge fuses can be inline fuse holder, fuse clips, panel mount fuse holder. We commonly see panel mount fuse holders on many electrical supply – they hold cartridge fuses inside a cylinder like enclosure and a top can be screwed with fingers to secure them in place.

How To Select Fuse in DIY Electronics

Supply from mains is easy to use fuse – they are standard household fuses. Glass cartridge fuse with panel mount fuse holders are practical. There are fuse holders for breadboards. But for ignorance, breadboard cartridge fuse and breadboard fuse holders are rare to ever see. There are companies who manufactures them but none ever think to add old good fuse with USB cable. We dissected USB cable for the sake of a guide. To be perfect, there should be inline fuse in USB cable for both for positive and GND. We are forced to depend on the circuit, circuit’s voltage control and cut off system. A MacBook Pro can blow away with a cheap China Arduino clone (Apple has extra protection but it will cost a huge to repair). Most of us are not educated like Thomas Edison to use special USB cables for power supply purpose or power-data combo USB cables a special category with inline fuse. Yes, USB cables with fuse exists.

Selecting and using a fuse for 3.3V, 5V, 6V, 9V, 12V DC supply is not easy. It is obvious that since the job of a fuse is to protect the wire by melting itself instead of the wire melting, using a fuse intended for 250V household supply will server too basic purpose. Voltage is not so big matter for the fuse wire over
the wire size gauge or rather Amperage. Such low voltage fuse needs quality checking by applying higher load.

Thankfully there are glass cartridge fuses for cars with Ampere values of 0.2A, 0.5A, 1A, 2A, and higher. Fuse rating = (watts/volts) x 1.25. After current value is determined, the fuse to be used it’s rating should be selected as to be 135% of the calculated. Amps (A) is equal to the voltage V in volts (V) divided by the resistance R in Ohms. Total resistance in series can be calculated with the equation R = R1 + R2 + R3 + … + n. Total resistance in series can be calculated with the equation R = R1 + R2 + R3 + … + n. Total resistance in parallel is 1 / R = 1 / R1 + 1 / R2 + 1 / R3 + … + n. Multimeter is shortcut to hard work. There is also clamp multimeter.

Arduino sucks 35 mA on USB. Original Arduino has onboard SMD fuse. 50mA cartridge fuse exists. These are 5 x 20 mm glass cartridge fuses and fuse holders should be for 5 x 20 mm glass cartridge fuse. There are PCB fuse holders. Most fuse holders are not breadboard friendly. If they are breadboard friendly, that will be written. They will cost higher. To prevent that exploit, you can buy any 5x20mm PCB fuse holder and solder male jumper crimp pin. You can search with “PCB fuse holder case with cover for 5x20mm fuse” for good looking Made in China fuse holders. Actually soldering male jumper crimp pins to glass cartridge fuse ends make breadboard fuse!