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#139313 11/02/03 06:35 AM
Joined: Dec 2001
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Oh, now I know what you mean. Completely overlooked that one. Yeah, that definitely isn't the most elegant of solutions.
That brass thing is the neutral connector block. A single phase circuit would have a second Diazed fuse instead of that block. In this type of fuse box there's no neutral bus bar, the neutral is a bus just like the phases, and depending on whether it's a 1ph or 3ph circuit there's a fuse or such a block in that position. The 2 3ph circuits in the bigger panel also have them.

#139314 11/02/03 09:05 AM
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why was the neutral fused?? is this just for extra safety or are there other reasons?

#139315 11/02/03 02:13 PM
Joined: Dec 2001
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The fused neutral thing started in the DC days, I think it was just for extra safety (the system was 220-0-220V 3wire Edison DC, i.e. +, - and neutral). Later on it turned out to be pretty handy when almost all of Vienna was converted to 3x220V AC (127/220V wye w/o neutral, i.e. you had just normal ungrounded recetacles but with 2 hots instead of hot and neutral), naturally requiring both phases to be fused. Today fused neutrals are pretty uncommon, but 1P + N breakers are still about the only type of brekaers used here. (They fuse the hot and switch the neutral).
As you can see, the Perilex 3-phase socket is fused with three individual breakers. This is not too common but perfectly legal here. If fuses were employed it would be impossible to link the three OCODs, so they don't see a problem with MCBs either.

#139316 11/02/03 03:10 PM
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I've never seen anything like it. All Swedish diazed panels have - and have always had - a metal cover. The design is also slightly simpler. (Kent posted a few pictures a year or two ago in this thread) I've only seen porcelain fuseblocks like this on 1930's panels. (But with a metal cover around them)

#139317 11/02/03 06:08 PM
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djk Offline
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Irish regulations are pretty specific about never ever ever absolutely never under no circumstances don't even think about fusing a neutral even where the live is also fused.

They like the idea of power being completely cut if there is any kind of overload.

----

#139318 11/03/03 08:04 AM
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Here's the promised pic of some other wiring in that place.
This is how the 100l hot water heater is wired:

[Linked Image]

Actually it should have a Schuko socket or flushbox with approved blank plate with strain relief.

And the plumbing isn't the most recent either.

[Linked Image]

Those open-vent gas water heaters used to be very common here, but become increasingly rare. At least this one isn't built into a tiny closet like the one I've seen in another church hall. (They stuck a note onto the door saying: "Do not operate while doors are closed!", but the pilot flame was on all the time.
BTW, the heater in the pic definitely needs a checkup, the pilot flame is at least twice as big as it should be.

#139319 11/03/03 05:04 PM
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djk Offline
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Very scary!

#139320 11/03/03 07:27 PM
Joined: Oct 2002
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Ranger,
You paint a very grim picture of Austrian electrical installations.
I don't like the panel without cover, it would be easy for someone to accidentally put their fingers into the back.
I have to agree with djk's comments on fusing the neutral, this has been prohibited in the UK for over 50 years. It would be acceptable to install a multi-pole linked breaker that also breaks the associated phase(s), but that is almost non-existent here.
As for the water heater connection, how could anyone leave such a bodge where it is accessible to members of the public, even if it was just a temporary connection.

#139321 11/03/03 08:48 PM
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djk Offline
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2 pole/ Multipole MCBs are certainly allowed here as they trip everything out simultaniously. A fused neutral would leave half the circuit live.

Multipole MCBs are generally not used in domestic installations though they only really crop up in systems where 3-phase is in use.

"one out all out" RCD and over current protection's compulsary in 3-phase. Older systems would have had 3 diazed fuses.
---

I will be much more careful of what i touch in austria if i visit! :P


[This message has been edited by djk (edited 11-03-2003).]

#139322 11/04/03 06:22 AM
Joined: Aug 2001
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The water heater connection is certainly a little less than ideal (<- That's British understatement! [Linked Image] ).

It's acceptable here to use a breaker which opens the neutral simultaneously with all phases, but very rare to actually see that done in practice. Isolation switches for water heaters and similar fixed appliances are double-pole, however.

Fused neutrals were common in 1930s wiring. My grandparents house in London still had some of this in the 1970s. They also had an Ascot gas water heater over the kitchen sink, very similar to the one in Ranger's photo.

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