Need help finding what is specifically wrong here

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Kadgarth

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Can anyone assist me with describing what exactly is wrong here?

I vaguely remember seeing something somewhere about a maximum number of strands a conductor can have, but can't seem to find it.

For reference, those are 2.5mm2 wires (at least according to the jacket).

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Looks like there is corrosion. Do you have a picture that is from further away also so we can see a little bit of the environment?
 
kwired said:
Are you asking about number of strands in a conductor or number of conductors within a cable assembly?
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I'm wondering about max number of strands in a single conductor.

Here is the widest angle picture I have of it. I'm not there anymore so I can't take another sadly. I'm writing a report as to whether or not the whole complex (like 15 buildings) need to be rewired.

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After thinking it over my best guess is that the CB failed to trip.

It seems really unlikely that the wire would burn up without tripping it, at least in my novice opinion.
 
Looks like the contactor or whatever that was failed as oppposed to the wiring causing the overheating.

What is that that burned?
 
Kadgarth said:
After thinking it over my best guess is that the CB failed to trip.

It seems really unlikely that the wire would burn up without tripping it, at least in my novice opinion.
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If there is a loose or corroded connection, the terminals will burn without tripping a circuit breaker because the current limit is never exceeded. As was already suggested, corrosion may have been the problem
 
Kadgarth said:
I vaguely remember seeing something somewhere about a maximum number of strands a conductor can have, but can't seem to find it.

For reference, those are 2.5mm2 wires (at least according to the jacket).
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You don't seem to be getting an answer to your question because "we" doubt the reason ... but stranding may vary quite a bit. 7, 19, 37, and 61 are popular with AWG cables, and likely metric; the numbers make good fills.

Take a look at http://www.seacoastusa.com/techconductor.htm for more than you want to know.

There has been discussion in the past on termination ratings with fine strand conductors; there are restrictions.
 
No evidence of an enclosure; tiled wall suggests moisture is expected (restroom?).

No evidence of an enclosure; tiled wall suggests moisture is expected (restroom?).

And you're concerned with the number of strands in a wire?
 
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"I'm writing a report as to whether or not the whole complex (like 15 buildings) need to be rewired."

If the same people that wired the power in the original photo wired the other 14 buildings, the answer is yes.
 
MichaelGP3 said:
"I'm writing a report as to whether or not the whole complex (like 15 buildings) need to be rewired."

If the same people that wired the power in the original photo wired the other 14 buildings, the answer is yes.
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Not necessarily. You would need to know what the installation was, if it met codes and standards and just exactly what the cause of the failure was. Could have been a freak accident that is not likely to be repeated. Could have been code compliant but had poor design otherwise. Could have been a good installation and someone came and changed something and now it is not a good installation.

I'm guessing there was a non metallic enclosure that pretty much burned up. Maybe a metallic enclosure would not have failed as catastrphically.
 
Non metallic enclosures for breaker panels seem common on the other side of the pond, (In Europe) I have seen many photos of installs over there, but I would have expected these cabinets to be flame retardant, but this one looks more like ABS plastic, funny thing with a plastic fire, the fire could have originated anywhere from inside to below it, because as the plastic burns it will drip down flaming balls of plastic and catch anything below on fire also making it look like it started from below, from the looks of this one it originated in the panel as was said, maybe from a bad breaker connection, the burned wires at the top are only the result of the flames from below as fire burns up.
 
After zooming in on the last two photos, it looks like the main lugs were to the right of the last breaker on the right, I would say this is where the problem originated at because this last breaker has far more outside damage to its right side, and other items in the area show far more signs of higher temperatures, adding the fact that these last two right breakers are not seated and are leaning out.

The controller or RCD unit? at the bottom left looks like a victim of just dripping flaming plastic as just the top is melted away.
 
hurk27 said:
After zooming in on the last two photos, it looks like the main lugs were to the right of the last breaker on the right, I would say this is where the problem originated at because this last breaker has far more outside damage to its right side, and other items in the area show far more signs of higher temperatures, adding the fact that these last two right breakers are not seated and are leaning out.

The controller or RCD unit? at the bottom left looks like a victim of just dripping flaming plastic as just the top is melted away.
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I have been looking at these pics until me eyes are going fuzzy and I think your right Wayne. I would really like to know more about the enclosure this was mounted in.... there is nothing left at all not even in back of the DIN rail.
 
First off understand that you are posting in a US based forum for our code systems, so most of us can only address NEC issues.

There is no specific code restriction here against using finely stranded or "extra flexible" wire. But we do have a generalized code requirement that equipment shall be connected in a matter suitable for the use and design of the equipment (paraphrased). What you WILL find is that the mfr of those specific MCBs may have a restriction as to the maximum number of strands in the wire it is connected to if you are using their built-in compression connectors. In mechanical connections like that, finely stranded conductors tend to squash out instead of compress, reducing the cross sectional area and leading to high heat in the connection. The proper way to make those connections would have been a crimp sleeve on the ends of those wires (or solder, but nobody does that now).
 
For those unfamiliar:

European breaker boxes are very different from what we use here. It's basically just a plastic box covering the DIN rail to which the breakers are mounted.

This is probably close to what it looked like before the fire.
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Most likely it got blown off by the fire hose, it appears to be hanging off to the left in one shot.
 
Jraef said:
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Most likely it got blown off by the fire hose, it appears to be hanging off to the left in one shot.
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I'm not buying it. No evidence of stains/debris on walls adjacent to the event consistent with the breakers being hit with a fire hose. No mention of the fireman being killed when he completed the circuit to ground with the water.

Do the boxes in your depiction have a backplane? Or is this not a box per se, but just a cover? I'm thinking that if it's the latter, I should retract everything I've stated earlier. I'm totally unfamiliar with this kind of installation.
 
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