Fuse blown and neutral wire sheathing melted.

[Jimmy Jones 1234]

I can read some text on the breakers. I would not be surprised if they were B16s. Is there really nothing visible?

Hears a pic of the breakers, the two on the left say 16A when I zoom in on the picture but I can't make anything out on the one on the right. I'm guessing they're all the same. Basically they used to be exposed in the kitchen with the previous house owner (to fat/ grease etc near the cooker) but when I moved in I covered this with drywall to keep them covered.

 

[pc1966]

Also the green wire to breaker 'I' on the left looks as if it is exposed coming out of the main wire, is it really an unsheathed earth that has been sleeved and put in to use as live?!

Or has the insulation perished and broken at that point exposing the conductor?

 

[Jimmy Jones 1234]

Three phase has the additional hazard that if the neutral is open you can get voltages of up to the 400V appearing on stuff that expected only 230V, you can guess how that is going to end...

Looking at your original burned out picture, is that wire aluminium by any chance? It looks suspiciously silver to me.

Do you mean the blue wire top left coming in? It is silver looking up close actually rather than copper but it is a really rigid wire, not soft or flexible at all like I would expect from aluminium, aluminium wires - is that even possible?

 

[pc1966]

Do you mean the blue wire top left coming in? It is silver looking up close actually rather than copper but it is a really rigid wire, not soft or flexible at all like I would expect from aluminium, aluminium wires - is that even possible?

You can get harder alloys of aluminium with a small amount of copper added, used for things like rally car under shields, etc, but possibly here.

That could explain the overheating, if you have aluminium against brass or copper it tends to corrode with any humidity at all and eventually you get thermal runaway, etc. It is very rare in the UK to see aluminium wire (outside of armoured cables above 50mm, and even then it is more of a thing in power networks than factories, etc) but more common in the USA.

If using aluminium conductors it is very important to take steps to avoid corrosion, typically by putting on contact grease to keep moisture out.

 

[Jimmy Jones 1234]

Also the green wire to breaker 'I' on the left looks as if it is exposed coming out of the main wire, is it really an unsheathed earth that has been sleeved and put in to use as live?!

Or has the insulation perished and broken at that point exposing the conductor?

I checked it now, I don't see any exposed wire anywhere on it. It's green sheathing but no idea if that is normal with soviet stuff. Lucien Nunes is more clued up on that I think.

 

[Lucien Nunes]

is that wire aluminium by any chance

It does have that sheen to it. Aluminium cables are common in some places (e.g. USA) and occasionally found elsewhere. If it's stiff it probably isn't Al, they are as soft as you imagine they would be, prone to making bad connections and overheating. They are not normally used for domestic wiring now due to these problems.

Also the green wire to breaker 'I' on the left looks as if it is exposed coming out of the main wire, is it really an unsheathed earth that has been sleeved and put in to use as live?!

I think it's a trick of the light. These cables did not normally have uninsulated cores, that's mainly a UK / USA thing. The cable is made to the traditional colour code for 3-phase during the Soviet era with green, yellow and red phases.

True TN-C seems very odd to us in the UK but much more common in older European and European-derived systems. There are a couple of reasons for that, including possibly the prevalence of 3-phase domestic and light commercial supplies that started out as 3-phase delta, and the later adoption of earthing as a protective measure in place of all-insulated construction. Sometimes only submains, sometimes all the way through the finals. I remember connecting the metal casing of fluorescent lights to the neutral of a 2-core lighting circuit in a German house in the 1980s and thinking it was the craziest thing ever, but got used to it.

 

[Jimmy Jones 1234]

It does have that sheen to it. Aluminium cables are common in some places (e.g. USA) and occasionally found elsewhere. If it's stiff it probably isn't Al, they are as soft as you imagine they would be, prone to making bad connections and overheating. They are not normally used for domestic wiring now due to these problems.



I think it's a trick of the light. These cables did not normally have uninsulated cores, that's mainly a UK / USA thing. The cable is made to old Russky standards with green, yellow and red phases.

Yes, it's really rigid. I tried to tighten the top screw in the terminal on the left just in case but I guess I overdid it and it didn't 'screw' anymore so I had to put the cable in the next hole down and it was a bugger to get in there with my big fingers with it being so tough a cable to bend. But when I shine a torch in there it is quite silvery looking and not like the other cables.

 

[pc1966]

Some info (or propaganda, take your pick) on aluminium wire if anyone is interested:

Aluminum Electrical Wire Information | The Aluminum Association

www.aluminum.org

Example of jointing compound:

Bicon X1 Electrical Joint Compound

Bicon X1 electrical joint compound by Prysmian is designed to prevent galvanic corrosion and to enhance connection in electrical joints. Get yours today online from Jointing Tech

www.jointingtech.co.uk

[automerge]1585413752[/automerge]

Yes, it's really rigid. I tried to tighten the top screw in the terminal on the left just in case but I guess I overdid it and it didn't 'screw' anymore so I had to put the cable in the next hole down and it was a bugger to get in there with my big fingers with it being so tough a cable to bend. But when I shine a torch in there it is quite silvery looking and not like the other cables.

It could be tinned (i.e. plated) copper wire then.

Not usually seen for domestic wiring but quite common for equipment wire, etc.

 

[Lucien Nunes]

Not usually seen for domestic wiring

Not these days, but historically most copper cable was tinned. With natural rubber insulation it stops the sulphur reacting with the copper, as well as improving connections generally.

 

[Jimmy Jones 1234]

Not these days, but historically most copper cable was tinned. With natural rubber insulation it stops the sulphur reacting with the copper, as well as improving connections generally.

Actually, the sheathing is very rubbery, so I think you are right. Your knowledge is pretty impressive, and your help very much appreciated. Not sure what my next step is now after cleaning up the wires, guess I just have to wait and see if anything happens again. When I tested earlier with everything on and plugged in and working that I could think of in the kitchen nothing got hot (or even warm) so I'm not much wiser, unfortunately. Hopefully, the cleaning up of the wires will do the trick but not sure I want to be doing this maintenance on a regular basis.

 

[pc1966]

If your damage-control has got it working OK for now then you should just keep a careful watch on it until it can be fixed properly.

It looked like they are 16A 'B' breakers, there is some small and just legible text on the lower part implying that, so you ought to be able to get replacements easily enough (maybe even mail order in the current COVID-19 situation). Considering what has happened I would not re-use them!

The terminal strip and box needs replacing as well, of course, and probably the wires all need cut back to good insulation and properly joined and extended if they are not long enough to reach the location. Wago make decent terminals and boxes for "maintenance free" joints where they can't be accessed for maintenance, I guess you can get them in Estonia OK.

However if you can get a competent sparky in they ought to deal with all of that for you.

You might also want to insist on a metal fire-proof box now, as the UK has done for the last few years!
[automerge]1585416465[/automerge]
Hopefully you checked all of the neutral block terminals are OK, in case the heat originated from one of them?

 

[Jimmy Jones 1234]

If your damage-control has got it working OK for now then you should just keep a careful watch on it until it can be fixed properly.

It looked like they are 16A 'B' breakers, there is some small and just legible text on the lower part implying that, so you ought to be able to get replacements easily enough (maybe even mail order in the current COVID-19 situation). Considering what has happened I would not re-use them!

The terminal strip and box needs replacing as well, of course, and probably the wires all need cut back to good insulation and properly joined and extended if they are not long enough to reach the location. Wago make decent terminals and boxes for "maintenance free" joints where they can't be accessed for maintenance, I guess you can get them in Estonia OK.

However if you can get a competent sparky in they ought to deal with all of that for you.

You might also want to insist on a metal fire-proof box now, as the UK has done for the last few years!
[automerge]1585416465[/automerge]
Hopefully you checked all of the neutral block terminals are OK, in case the heat originated from one of them?

Thanks for the info, I will certainly do this, I'll order parts online and do it myself for now until the crisis blows over and I can get an electrician in to check everything over. The neutral block terminals - do you mean the same block where the neutral and earth wires are connected? Yes I checked all these for tightness but the top one (where the main neutral wire came in from the garage), this screw wouldn't tighten, the thread was crossed somehow it seemed. Not sure if the heat has done that or whether that might have been the initial fault - the wire seemed securely fastened but when I unscrewed it the screw just turned but did nothing. So I moved the wire down into the next hole in the terminal. I keep a check on it several times a day, all is cold to the touch, no heat (fuses) but still, I'll switch these out to be safe.

 

[pc1966]

Yes, it seems you have a TN-C system where earth and neutral are common within your installation - this is something that is prohibited for most UK setups. So that terminal strip is for both.

Here in the UK you can buy small metal enclosures typically for garages, etc, that would probably do if you can physically fit it into your home. I don't know if they are available in Estonia as much, but here is an example of what I am talking about:

Metal Garage or Shower Unit IP65 Empty Body

Neutral and earth terminals, DIN rail, neutral cable and busbar included

www.cef.co.uk

In your case you would not be using any sort of live busbar as you have 3 separate phase cables for each of the MCB, but otherwise you get the metal box and DIN rail, along with built in terminal strips. Ideally you get glands to seal the cables as they enter, which should always be done for top-entry cables to avoid screws, etc, dropped from above making it in to the unit, but in most cases folk just use grommets for side or bottom holes.

 

[Lucien Nunes]

Estonian electrical material is mainly same as German, CU's are different to ours. Plastic flush or surface mounted CU and conduit cables / NYM are standard for domestic work. Hardly anything is metal, e.g. flush back boxes always plastic. See pics for a flavour, taken at a shed (Bauhaus) near Tallinn. You can buy all components to make what you want, box, main switch, busbars, terminal bars, RCDs, MCBs, RCBOs, everything is on the shelf.

 

[Mike Johnson]

That looks like any Brico Depot or Leroy Merlin electrical isle in France, all available off the shelf.

 

[freddo]

You can buy all components to make what you want, box, main switch, busbars, terminal bars, RCDs, MCBs, RCBOs, everything is on the shelf.

Those photos show more stock quantity and range than any of my local wholesalers.

 

[Lucien Nunes]

It's Bauhaus, knocks the socks off any of our sheds over here. 3 Aisles of screws, you can buy by the kilogram or individually and there's no stupid price penalty for small quantities. All the marine fixings for example are one price per material grade - you just tell the scale whether it's 302SS, 304SS, bronze etc. and chuck in what you want and print the label.

Same for cable - buy a pre-pack or wind it down from the drums - automatic measuring and coiling.

 

[Mike Johnson]

Do they also have the corrugated conduit with draw wire as the French Sheds? Oh and the pre-loaded conduit as well?

 

[Jimmy Jones 1234]

Estonian electrical material is mainly same as German, CU's are different to ours. Plastic flush or surface mounted CU and conduit cables / NYM are standard for domestic work. Hardly anything is metal, e.g. flush back boxes always plastic. See pics for a flavour, taken at a shed (Bauhaus) near Tallinn. You cu suggested however the problem persists and is getting worse. I fear for my life in that it might burn down but I haven't been paid in such a long time i don buy all components to make what you want, box, main switch, busbars, terminal bars, RCDs, MCBs, RCBOs, everything is on the shelf.

Hi man, it's been a while. I did everything yo

Estonian electrical material is mainly same as German, CU's are different to ours. Plastic flush or surface mounted CU and conduit cables / NYM are standard for domestic work. Hardly anything is metal, e.g. flush back boxes always plastic. See pics for a flavour, taken at a shed (Bauhaus) near Tallinn. You can buy all components to make what you want, box, main switch, busbars, terminal bars, RCDs, MCBs, RCBOs, everything is on the shelf.

Hi again, I did what you suggested, everything has been okay for a long time but, today lots of fizzing and popping on the wires in this fuse box. I haven't checked it for ages but it seems worse now when i look at it. I can't afford an electrician at the moment with covid, no salary, but I am afraid it might burn the house down. I don't know what to do. I can't just turn the fuse off, everything is connected here, lights, kitchen, bathroom etc, then we are screwed. I don't know what to do, anyone?

 

[Lucien Nunes]

Which wires, where exactly? Post clear close-up pics. Need to distinguish between bad connections at the terminals and any other kind of problem such as bad contact inside the circuit breakers.