Poor neutral in rcd and burn marks!

[Gavin John Hyde]

Been around a friends house today for dinner and whilst there the rcd tripped. Its been tripping on and off it seems since they moved in. Especially when the cooker and kitchen are using lots of aplliances.
Had a look and the neutral in the bottom was barely secured. I could pull it out. The strands were crushed and forced in rather than being a nice cord to terminate well.
There was also a unsleeved cpc that was far too long and running below and looped back up behind.
So not sure if the loose neutral caused the burn marks on the bottom of rcd or there is another fault with something running through the cpc?
Have checked and sorted out for now but the annoying thing is the house is barely a 4 years old and they are the second owners having bought it last month!! Very poor workmanship and they loads of things to put right in this house. The last owner had done bits of work as they added a new circuit with a rcbo for the garage and it looks like everything has been moved around to accomodate.
There may or may not be a certificate for this work. They are going to check with their solicitor who has the papers.
Im going back tomorrow to do some further investigations.
Thoughts?

 

[Gavin John Hyde]

Another picture taken on phone. The brown marks feels oily rather than a burn mark and maybe some sort of oil from the insulation? The blue cable has blackened insulation.

 

[Octopus]

Reality of new home builds .........

 

[Ian1981]

The neutral tail looks like it was loose causing arcing
The installer does not connect this into the rcd tho most if not all new consumer units come with a note recommending that manufacturers connections are checked for tightness.

 

[Gavin John Hyde]

The neutral tail looks like it was loose causing arcing
The installer does not connect this into the rcd tho most if not all new consumer units come with a note recommending that manufacturers connections are checked for tightness.

Was my first thought too, it looks as if its been pulled about a bit to fit the rcbo in on the din rail and come loose or not tightened properly to begin with.
Worryingly there are probably thousands of homes with similar electrics out there...

 

[Ian1981]

Was my first thought too, it looks as if its been pulled about a bit to fit the rcbo in on the din rail and come loose or not tightened properly to begin with.
Worryingly there are probably thousands of homes with similar electrics out there...

It could be that the installer removed it when mounting the consumer unit originally and removed the inner ‘guts ‘ if you will and has failed to tighten it correctly.

 

[telectrix]

what make is that board?

 

[Gavin John Hyde]

what make is that board?

Hager believe it or not! the terminal was functional if only a bit stiff when you tightened the screw. Its rare to find a fault with a Hager which makes me think installer issues when something has been done in the unit. I did read somewhere that a lot of the tails for in CU's were going to have the insulation impregnated with fire resistant material to prevent or slow fire. not sure what came of that idea..
Note the innards are Hager but the actual CU didnt appear to be Hager, i will gave to double check tomorrow when i am back there.

 

[Strima]

No ferrule on the cable wouldn't help either.

 

[Des 56]

I know you said the connection was loose but from what I can see,the cable core and the connection are still clean metals

The scorch mark also looks like it is from inside, possibly near the terminal of the Rcd,maybe the marks on the tail are from heat off the Rcd rather than vice versa

 

[Gavin John Hyde]

I know you said the connection was loose but from what I can see,the cable core and the connection are still clean metals

The scorch mark also looks like it is from inside, possibly near the terminal of the Rcd,maybe the marks on the tail are from heat off the Rcd rather than vice versa

It confused me when i saw it, as the metal is still bright and the middle still retains some sort of square with lots of loose twisted strands around it, which made me think it had been taken out and pushed in a too small a gap, the edges of the connector forcing the strands back to be untidy.

Could a RCD terminal if touching the insulation cause that ? In part i would assume its down to the current flowing and resistance that builds up....as said already the brown mark is oily as if something has come from the insulation. I will have a better look tomorrow when there.