[earplay]

Well, I didn't think I was this uninformed, but....

Okay, here goes... I recently ordered an IEC inlet for a project I'm planning. The inlet is a Furutech FI-03 (G). I take that to mean it's Fused Inlet with Gold plating. That's what I wanted.

I just received this thing and I noticed that it is rated for 250v and says to intall a fuse with a 250v rating. I'm in the US. I'm running off ordinary household current. My project is for my home system.

So, my question is, do I use a 250v fuse or should I use a fuse with a 125v rating? 

[srb]

Use a 250V fuse if you can find it.  You are most concerned with the current rating (A) and fuse type (fast-blow or slow-blow) that the circuit requires.
 
The voltage is the maximum the fuse can be used at, so you can always use one with a higher voltage rating.  If you use a 125V fuse, and your line voltage ran high, say to 135V, it might be possible to arc across the terminals even if the fuse is blown.
 
Steve

[Wayner]

Under the UL component recognition program, 250 volt is the lowest voltage rating for devices that run off 120 volt design standard. This in particular, has more concern with insulation rating and arc resistance of the device and is higher then it's operating voltage, to give it a safety margin. The more you do DIY projects, you will notice this rating on lots of 120 volt use components, like switches, outlets and the likes of that.

Have fun.

Wayner 

[earplay]

Thanks guys! Got it. I know electricity can be compared to water flowing. While I don't get the simple relationship between watts, amps, volts, etc., if I really wanted to know, I could find out. I may end up needing to know this info in the long run.

I was concerned that the fuse voltage was double the input operating current of the amp. This higher voltage might allow too much current into the amp before it blew. Now that you've explained it, I can see how the voltage rating of the receptacle would be high to create a safety margin.

Rating the fuse high, though, seems to present a danger to the amp. I know there are spikes and some household voltages run high, but I didn't know if a 250v fuse would provide the protection my amp will need. It's just a little class D amp. It seems delicate compared to my old, heavy and industrial-looking tube amp.

If you say it's okay to use a 250v fuse, I'll do it, but it seems too high to me given how I (mis)conceptualize what's going on.

Thanks again for you comments. The project is on again. 

[Tone Depth]

With 250V fuses, I think you want to pay attention to the fuse amperage rating, to control wattage to your speakers.