Products certifications, safety requirements (and creepage distance)

VT67 · 17th March 2005, 08:57 PM

For those still looking for the fuse!

Peter Daniel · 17th March 2005, 09:33 PM

There are few reasons I opted for soldered fuse:

While using 3 x 2 tubing, there is not enough space for fuse socket underneath.

From the standpoint of reliability, soldered connection is always better than tiny clamps of a fuse holder.

While the fuse I'm using in a picture, is not particularly suited for direct soldering, it still worked well for the last year I've been using it like that in another circuit. Digi Key has few pages of fuses that are made specificaly for direct soldering to the board.

And lastly, a properly designed device, shouldn't require fuse change in its lifetime, so why would you need a socket for?

peranders · 18th March 2005, 07:18 AM

Ok, I found the fuse but isn't many fuses soldered inside? Do the manage soldering without any problems?

I see also (correct me if I'm wrong) that your creepage distances are way too narrow, at least for 230 volt countries.

You must have 8 mm between any mains parts to any touchable metal part and in your case it will be your whole stereo.

Hanzwillem · 18th March 2005, 08:01 AM

There is nothing teflon tape wont insulate

Vikash · 18th March 2005, 08:44 AM

If you look at the PCB's and the case it looks like there is space to fit a taller, fused IEC conenctor. This will satisfy the safety/creepage issue - why all the fuss.

Vikash · 18th March 2005, 09:26 AM

ooops. I see why the fused IEC isn't an obvious option now. I saw the connectors were exiting at around mid height of the case, so there appeared to be some space available to fit a taller IEC socket. But now I've noticed that it isnt the same PCB in the case.

Vikash · 18th March 2005, 09:41 AM

Had a look on Farnell; fused pcb iec sockets are about 8mm taller compared to their non-fused counterparts.

pinkmouse · 18th March 2005, 09:46 AM

When I buy one of these kits, I am going to just make the enclosure slightly longer, and mount a fused IEC, or IEC and separate fusefolder off the pcb.

Peter Daniel · 18th March 2005, 01:58 PM

Quote:

Originally posted by peranders
Ok, I found the fuse but isn't many fuses soldered inside? Do the manage soldering without any problems?

I see also (correct me if I'm wrong) that your creepage distances are way too narrow, at least for 230 volt countries.

You must have 8 mm between any mains parts to any touchable metal part and in your case it will be your whole stereo.

There may not be many fuses soldered inside, but this one is. This was an intentional choice. There is a lot of talk about mains connection quality, higher grade receptacles and all those "special" power cords. I simply didn't want to compromize the AC interface by choosing "convenience" over quality. The fuse attachment pads are oversized, so basically any type of fuse can be used here and I still have to experiment what works best. I'm also of opinion that the type of fuse will affect the sound, so the choice is not merely picking sub-mimiature type from D-K catalog. The practicality was never the intention of this product, the best example is the way some caps are mounted.

As to the creepage distance, it is only dictated by the standoffs height. In case of .25" it's about 6mm and with .375 we are well over 8mm. Additionally, the enclosure surface directly under the AC traces and the fuse, can be insulated with special plates.

Peter Daniel · 18th March 2005, 02:10 PM

I just had a quick look through D-K catalog, and this fuse seems like an interesting choice: http://rocky.digikey.com/WebLib/Belf...%20Data/MQ.pdf

17th March 2005, 09:33 PM	#2
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	There are few reasons I opted for soldered fuse: While using 3 x 2 tubing, there is not enough space for fuse socket underneath. From the standpoint of reliability, soldered connection is always better than tiny clamps of a fuse holder. While the fuse I'm using in a picture, is not particularly suited for direct soldering, it still worked well for the last year I've been using it like that in another circuit. Digi Key has few pages of fuses that are made specificaly for direct soldering to the board. And lastly, a properly designed device, shouldn't require fuse change in its lifetime, so why would you need a socket for? __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

18th March 2005, 07:18 AM	#3
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	Ok, I found the fuse but isn't many fuses soldered inside? Do the manage soldering without any problems? I see also (correct me if I'm wrong) that your creepage distances are way too narrow, at least for 230 volt countries. You must have 8 mm between any mains parts to any touchable metal part and in your case it will be your whole stereo. __________________ /Per-Anders (my first name) or P-A as my friends call me

18th March 2005, 08:44 AM	#5
Vikash diyAudio Moderator Emeritus Join Date: May 2003 Location: UK	If you look at the PCB's and the case it looks like there is space to fit a taller, fused IEC conenctor. This will satisfy the safety/creepage issue - why all the fuss. __________________ "The human mind is so constituted that it colours with its own previous conceptions any new notion that presents itself for acceptance." - J. Wilhelm. (But I still think mine sounds better than yours.)

18th March 2005, 09:26 AM	#6
Vikash diyAudio Moderator Emeritus Join Date: May 2003 Location: UK	ooops. I see why the fused IEC isn't an obvious option now. I saw the connectors were exiting at around mid height of the case, so there appeared to be some space available to fit a taller IEC socket. But now I've noticed that it isnt the same PCB in the case. __________________ "The human mind is so constituted that it colours with its own previous conceptions any new notion that presents itself for acceptance." - J. Wilhelm. (But I still think mine sounds better than yours.)

18th March 2005, 09:41 AM	#7
Vikash diyAudio Moderator Emeritus Join Date: May 2003 Location: UK	Had a look on Farnell; fused pcb iec sockets are about 8mm taller compared to their non-fused counterparts. __________________ "The human mind is so constituted that it colours with its own previous conceptions any new notion that presents itself for acceptance." - J. Wilhelm. (But I still think mine sounds better than yours.)


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18th March 2005, 08:01 AM	#4
Hanzwillem diyAudio Member Join Date: Nov 2002 Location: Hengelo, The Netherlands	There is nothing teflon tape wont insulate

18th March 2005, 09:46 AM	#8
pinkmouse diyAudio Moderator Join Date: Apr 2002 Location: Chatham, England	When I buy one of these kits, I am going to just make the enclosure slightly longer, and mount a fused IEC, or IEC and separate fusefolder off the pcb. __________________ Al I conceive of nothing, in religion, science or philosophy, that is more than the proper thing to wear, for a while. Charles Fort

18th March 2005, 02:10 PM	#10
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	I just had a quick look through D-K catalog, and this fuse seems like an interesting choice: http://rocky.digikey.com/WebLib/Belf...%20Data/MQ.pdf __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

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