125v Fuse with a 250v One?

I was looking everywhere in the UK for a 1.25A 125V fuse and nowhere sold them. I was told in Maplins I could use a 1.6A 250V fuse.

I am replacing the fuse in my MPC 60, the one at F1. Would this work, or could this damage the MPC if more than 110V went through the MPC?

I have a converter that outputs 110V (UK->US power converter) and it works with devices up to 50/60Watts (with the MPC 60 being 35 Watts).

Does the above sound good?

You can use a fuse rated at 250V. Try to match up the current as best you can. The fuse has the ampere rating for a reason. You should be able to find one as 1.25 is not uncommon.

Remember that spark you saw?
You saw that thanks to the 125v fuse a 250v would have given you smoke, damaged components etc when the wrong input voltage was supplied.
If the step down fails, gets a surge or anything along those lines you will regret having the 250v fuse in there.

Use it to get up and running but understand the risk of incorrectly rated fuses and just order the correct ones.

I got the MPC working with the 250V fuse. A few people of said such a slight change in the amps won't make a difference with appliances/computers and such like.

I've also been informed about 10 minutes ago that a fuse does not blow because of the volts, it blows because of the amps.

But, to be safe I have ordered a 125v 1.2a fuse from online. Just to be safe

No components burn up because of volts, the fuse is to prevent the the problem from getting to and damaging components.
It's a safety factor that you want to be correctly in place.

Glad you got the 60 working.

I feel your pain James, but three threads on the same thing?

Different chapter, same story.

Keep it all together in one thread next time.

Glad you got it sorted in the end!

Clint

Never use a fuse other than the one specified. If you get one greater or lesser than 125 then you'll short out your machine even a meltdown.

Ill-Green wrote:Never use a fuse other than the one specified. If you get one greater or lesser than 125 then you'll short out your machine even a meltdown.

No. This is a very common misconception.

For fuses, the voltage rating does not matter as much. Technically a 250V fuse is more sensitive than a 125V one.

It is very important to match the current rating when replacing a fuse.

Current is a measurement of the flow of electricity. The fuse is there to protect the circuit when the current flow is too great. The fuses blew in the unit because it was drawing greater current due to the wrong voltage which was likely shorting out the internal transformer.

No the misconception is people don't understand the effects of voltage, current and power within a given circuit.
The wrong voltage causes problems just like wrong current, they just have a different affect on the circuit.

Remember that fundamental formula they taught you when you first went to engineering class P = I × V?
If you change I or V you will affect the circuit as well as P.

Sovereign wrote:No the misconception is people don't understand the effects of voltage, current and power within a given circuit.
The wrong voltage causes problems just like wrong current, they just have a different affect on the circuit.

Yes, P = I x V. .

But you are confusing the voltage rating of a fuse with a operating rating. They are not the same thing.

Sovereign wrote:Remember that spark you saw?
You saw that thanks to the 125v fuse a 250v would have given you smoke, damaged components etc when the wrong input voltage was supplied.

If the step down fails, gets a surge or anything along those lines you will regret having the 250v fuse in there.

Use it to get up and running but understand the risk of incorrectly rated fuses and just order the correct ones.

As the voltage and/or current move closer to infinity the fuse will trip. Any event of a short or surge is many orders of magnitudes greater than the regulated voltage or current. You would be lucky to gain even an extra microsecond of protection.

As long as the current rating for the fuse matches what is being replaced, there will not be any damage to the circuit.

If you sleep better at night using 125V in place, then by all means do so. But it's certainly not going to hurt anything if the OP uses a 240V fuse in its place.

Interesting stuff.

I was never any good at electronics.

thanks for the info - I had to replace some fuses in a 60 yesterday - radio shack only had 250v ones, but the correct current rating - I figured they'd be ok.