I need to replace an AH 10A 250 V glass type fuse and the closest I have is an AGC 10A 32V fuse. They are the same physically, but are they the same electrically? The actual fuse element inside the 32V fuse looks thicker than the 250V fuse.
You can substitute a higher voltage rating for a lower one, but not the "other way" around. The 250 volt rating means the fuse will safely open a 250 volt circuit without "exploding" or developing an interal arc which could maintain current flow longer than would be safe.
Keep looking...
Jeff
If the voltage the fuse is controlling is 32V or less, it will be fine. If it is a 115V appliance - not so.
Bob
Others have already answered the question of using a lower voltage-rated fuse in a higher voltage application as a definite no.
As far as the apparent visible size of the element from one fuse to another, that's a design consideration related to the material composition, fuse response time, etc. Since dissipated power is I^2 * R, the current to melt the fusible link is dependent on R which is obviously intimately related to the material, etc.
Thanks for all of your inputs. I look for the right fuse.
Is this for a microwave, proper replacement fuses are available at many stores.
The 32 volt fuse may not interupt the fault without blowing up.
32V one is most likely for DC circuit use.
A simple fuse doesn't care if it's AC or DC, and there are low-voltage AC circuits that need fuses. What does matter is the voltage rating.
Zero crossings may be used by AC fuses to help extinguish the arc. Some fuses are AC only, some have lower voltage ratings on DC.
Swithes have AC-DC limits also. Quiet switches we commonly use break the circuit slowly and use the AC zero crossings to help extinguish the arc. Quiet switches are probably all AC-only. DC requires a fast snap action.
-- bud--
replying to Bud--, Chris Harmon wrote: Most others will say I am crazy to say otherwise but you could probably use a
32v with some changes to the amperage. The reason the 32v fuse looks thicker is because efficiency goes down with DC 32v vs AC 120/240v. I don?t have the means to properly test this but I would imagine if you needed a 10A 125v fuse you could probably use a 32v 3A as an equivalent. My reasoning is the CNC milling machine I have that blew a 250v 10A fuse is actually rated for 115VAC input and outputs 90VDC with a motor that?s rated for 8 amps yet it blew my 10A fuse quite easily(barely any load or heat from variable controller) so in reality it was likely closer to a 3.5-5 amp fuse at the voltages of 115 and 90. My guess is that a 32v 3 amp would probably be close to a 11-12 amp 250v fuse which is close enough IMO.
Your IMO is totally wrong.
A fuse is made to blow at a certain current. The voltage rating will have no effect.
Where the voltage comes in is the ability of the fuse to interrupt the flow of electricity. If the voltage rating is too low, it may be possiable for the fuse to arc over and still pass current.
If you stick a 3 amp 32 volt fuse in a 240 volt circuit that needs 5 amps or over, it will blow almost like an old time flash bulb.
It may even arc over and not even stop the current flow.
Many of the old car fuses that are rated for 32 volts were different sizes depending on the current rating to keep people from putting the wrong fuse in the holder.
amps yet it blew my
Another way of looking at that is that a fuse is essentially a low ohm resistor that gets hot based on how much current is flowing through it. The power generating the heat is I2R, which is not voltage dependent. When it gets to the rated current it gets hot enough to melt and open the circuit. Like you say the voltage rating is related to other factors. I'd add another factor is what kind of holder it's designed to go in, the insulation rating, contact ratings, listing, etc. for it too, not just the fuse. They are designed together.
What he said. Sounds like what I know.
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