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#136315 - 03/25/03 10:55 PM I'll just "fix" this fuse
C-H Offline

Member

Registered: 09/17/02
Posts: 1508
Loc: Stockholm, Sweden
Here's a photo I found on the Polish forum ( in this thread )



As I understand it, someone had 'repaired' a fuse with a bit of wire. I know nothing more about it, I just thought the photo was a good illustration of the result of overfusing.

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#136316 - 03/26/03 11:14 AM Re: I'll just "fix" this fuse
Bjarney Offline
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Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
C-H, are those diazed fuses common in some areas of Europe? Diazed fuses have been periodically discussed in this “Non-US…” E-C.net forum.

{For the benefit of US electricians, they are somewhat like local edison-based fuses, but are rated 1-63 amperes. They are closer in design to the US "type-S" fuse, in that you can't cheat by putting a bypassing penny in the shell base.}

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#136317 - 03/27/03 06:44 AM Re: I'll just "fix" this fuse
C-H Offline

Member

Registered: 09/17/02
Posts: 1508
Loc: Stockholm, Sweden
Yes, these look like Diazed II (medium size) fuses, although the panel(s) doesn't look like the ones I'm used to.

The Diazed is a pre war design, which means that its spread needn't be limited by the iron curtain. I know that they are used in Germany, Scandinavia, Ireland, Switzerland, Austria and I think also in former Yugoslavia. And Poland it seems. It is very likely that they are used in many more countries.

[This message has been edited by C-H (edited 03-27-2003).]

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#136318 - 03/27/03 07:34 AM Re: I'll just "fix" this fuse
Texas_Ranger Offline
Member

Registered: 12/17/01
Posts: 2343
Loc: Vienna, Austria
Strange. It looks as though they're grouped, sometimes 3 in a group, sometimes 4. i also can't guess what has been in the empty space between the fuse blocks. Meter(s)?
A real pity I don't understand polish. Jacek, maybe you can help us here? I'd like to know more about that incident.
Maybe I'll try to ask a polish-speaking classmate of mine tomorrow.
Guess than panel already looked quite bad before burning down.

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#136319 - 03/27/03 11:55 PM Re: I'll just "fix" this fuse
Texas_Ranger Offline
Member

Registered: 12/17/01
Posts: 2343
Loc: Vienna, Austria
I was told that the original post is more or less the following: This is an old style panel. Its bottom part is severely burnt. There's no meter.
And there's something with 0.75 mm2, my classmate couldn't really translate it since she doesn't know all the technical slang, neither polish nor german.
The post seems basically to state the obvious.

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#136320 - 03/28/03 05:19 AM Re: I'll just "fix" this fuse
djk Offline
Member

Registered: 12/26/02
Posts: 1269
Loc: Ireland
In Ireland Diazed is only acceptable in old installations, the fuses are still widely available and that panel looks "fairly" familiar. I've seen fuses grouped like that before. Older panels wern't necessarily one single unit either, you might have 2 or 3 small panels feeding socket radials and light radials and single fuse panels serving the cooker and heaters. Although i've also seen huge Diazed panels with upwards of 100 fuses on them in old buildings, particularly former institutions. They were feeding radial Schuko or BS546 (15amp) usually.

There was a concerted effort to remove the oldest generation of diazed panels here in the 1970s I think the very old ones were a potential shock hazard as you could contact the live terminal of the fuse receptical very easily while changing the fuse particularly in the dark. The old "NDZ" fuses were very large. There are still plenty of "DZ" and more modern Neozed panels around though.

Neozed is still an acceptable alternative to MCBs as long as RCD is fitted and that the fuses arn't too slow blowing. Although I can see no reason why they'd be used when good MCBs are now available. I think during the 1960s and 70s the reliability of MCBs wasn't really established.
Did older MCBs jam?

The regs here still require one 63 amp Neozed fuse on the board. I guess as it's non-mechanical it can't jam and would prevent a fire if a large breaker didn't trip.

The more modern meters also include a double pole isolating switch on the bottom. On installation you wire the terminals on the bottom of the meter, sign the paperwork and have it sealed. The idea was that the ESB wanted to provide 100% reliable isolation from the mains on the customer side to eliminate any risk of shock you can fully isloate the entire customer installation.

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#136321 - 04/03/03 01:45 AM Re: I'll just "fix" this fuse
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8540
Loc: SI,New Zealand
C-H,
It must be worrying, replacing one of them
fuses, are they High Rupturing Capacity?.
Have you ever heard of anyone beng injured when replacing these fuses, with a serious fault on the circuit?.
BTW, that panel has been REALLY hot during the fire, you can tell by the white discolouration at the bottom of the picture,
I'd say 4-500 deg C, at a guess.
There's a FEW people that I would love to show this pic to!.
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin

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#136322 - 04/04/03 03:41 AM Re: I'll just "fix" this fuse
C-H Offline

Member

Registered: 09/17/02
Posts: 1508
Loc: Stockholm, Sweden
The smallest and very rare Diazed I fuses are a PITA to replace, because of poor mechanical design.

The bigger versions are easy and safe to remove and insert. 500V rating and IIRC a 50kA breaking capacity.

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#136323 - 04/04/03 08:10 AM Re: I'll just "fix" this fuse
Texas_Ranger Offline
Member

Registered: 12/17/01
Posts: 2343
Loc: Vienna, Austria
It only becomes a bit scary when the glass on the screw cap is missing and there might be a short in the line. This gives the possibility of a nice arc shooting out of the back of the screw cap. Otherwise I don't have any problems changing Diazed fuses. They're even legal for new installations, though rarely used.

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#136324 - 04/09/03 01:55 AM Re: I'll just "fix" this fuse
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8540
Loc: SI,New Zealand
Does anyone know where I can see some pictures of these two types of Fuses?
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin

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