Glowing cables

[BlueToBits]

I usually do commercial work these days, but I attended a domestic call out today. I don't do this very often but I happened to be passing on the way to another job. The customer was complaining of funny smell since last night coming from her consumer unit.
I entered the house to a haze of smoke and a stench of burning plastic.
So, after removing the cover of circa 1990 squareD board, I noticed a bright yellow glow coming from the under the MCB cable entry (these boards have a top busbar). Everything was far too hot to touch. A 2.5mm cable had burned almost right through, and was glowing like a filament and had clearly been cooking the consumer's unit for quite some time. I should have taken a photo but was too alamed to think about it at the time.
I've seen the aftermath of an electrical house fire several times, but this is the first time I have seen the beginnings of what would have almost certainly have become one.

Just thought I would share this.

 

[BlueToBits]

Looking at the remains, I recon that:
It was the cooker spur that was loose in the connection at the MCB terminal that started things off. I suspect that the installer had the cable wedged in behind the cable clamp arather than in it. It's difficult to see without getting on your back and looking up.
This heated up the termination with the and the good (or at least better) connection of the ring main cables
The ring main cables oxidized over a period of time and as a result lost much of their CSA.
These cables then glowed and accelerated the oxidation effect resulting in thermal runaway as one leg of the ring melted away. At the point I arrived, the cooker connection was still arcing and the remenants of what was once a 2.5mm leg of the ring glowing under the connected load.

The client sais she has occasionally been able to smell a strange "perfume" spell for some weeks. It was only when her son opened the cupboard did they realise this smell was coming from the CU.
The board was fitted by a freind of the family in 1996. The 2.5 cables have a 1mm CPC so I recon the installation is mid-late 70s. She has never had an inspection. On the certification for the new CU, I recommended that a full PIR be undertaken. - She said she would think about it....

 

[DurhamSparky]

She said she would think about it....

i bet if it had been her gas boiler or brakes on car she would not think about it...!!! what dumb bimbo....! next time let the house burn down.... let her think about ringing the fire service..!

 

[telectrix]

apologies for the hijack here. problems with site. anyone help. yesterday all fonts/printing etc. went microscopic. this morning while messing about i got into mobile style. now i can't get anywhere except for existing threads to reply . HELP!!!

 

[Geordie Spark]

i bet if it had been her gas boiler or brakes on car she would not think about it...!!! what dumb bimbo....! next time let the house burn down.... let her think about ringing the fire service..!

Divvent kid yersel' bonny lad ........ I've seen some horiffic situations with boilers & gas fires that the client wasn't too worried about because "it's working innit?"

Soon changed that though - when I disconnected & capped them off !!

 

[nickblake]

One thing if it was on a ring main with open circuits on the lives together with a loose connection then you would get the load of that half arching at the MCB , see it befor with melted cables at the MCB where the full load of the ring was on one leg due to the open circuit so overloading the cable causing both to break down

i am quite suprised they left it so long especially as you said there was a haze of smoke in the room , totally agree with durams comment as myself and he have been in house fires !!!

 

[tony mc]

The client sais she has occasionally been able to smell a strange "perfume" spell for some weeks

I wonder what sort of Perfume she uses ???

 

[DurhamSparky]

Chloe "smoked out"

o was it

Britney Spears " Taint of Fishy Fanny"

 

[BlueToBits]

She was actually quite nice. Fairly typical as customers go, she even dug out the camping stove to make tea. My better half can't smell a thing so be it cheap perfume or acrid smoke, so I could have been coming home to ashes. Most people only get a PIR done as a result of a house purchase, and then only if a surveyor recommends it. My house installation is 16 years old and has been abused as an apprentice training ground. I have never done a PIR! Sounds like I have another job for next week.
Now, what shall I charge for it and how many of my own defects will I be correcting? I can think of one or two that won't - they will probably won't even be discovered....

 

[DurhamSparky]

i do ya PIR for £30 quid.. give me ya address and i will post it to you.!!

2 rings 2 lights a a cooker and shower?? yeah!

 

[BlueToBits]

i do ya PIR for £30 quid.. give me ya address and i will post it to you.!!

2 rings 2 lights a a cooker and shower?? yeah!

Discount for cash?

 

[DurhamSparky]

yeah 50%

 

[johnboy6083]

if ever i get a termination that has a central screw, and space either side of that for conductors, then i wil use a fork crimp. if i need 2 conductors in that termination, then i will piggyback them. ive seen a few isolators for small pumps burn out because of these terminations not being done properly. its not worth the shortcuts in my opinion