Nightmare....!

[sythai]

Been up for last hour having MI nightmares :rolleyes4: cant wait to get round there this morning to see if I can figure out what the issue is.

 

[Thefailsafe2012]

Hope it goes well mate, I'm off to help the guvnor do some testing in Essex, shu' uppp! :cheesy:

 

[sythai]

Hope it goes well mate, I'm off to help the guvnor do some testing in Essex, shu' uppp! :cheesy:

Cheers Mate

 

[Lucien Nunes]

If the RCBO tripped exactly when you hit the cable as a result of the hit, there must have been metal-to-metal contact because it would take time for moisture to to get in and take effect. Unless you chew into the sheath of this is unlikely because as has been mentioned above you can crush it flat and the insulant still holds the conductors apart. So this suggests to me that a nearby faulty seal was disturbed by the hit or the cable was already damaged somewhere. 250V grade is probably more likely to be damaged because of the smaller dimensions.

When looking for a fault site, especially as there has been a lot of moisture around recently, you don't need much heat, just pass the heat gun along the cable watching the tester, as soon as you reach it the reading will change. It may even be possible to find it by warming the plaster without exposing the cable.

Lucien

 

[UNG]

I have honestly never heard of MI being used for any domestic purpose

It was quite often used in flats, at one time BICC used manfacture to the building spec pre terminated MICC wiring kits

Thanks Chaps for all your advice it really is appreciated.... Doing my nut in/ sleepless night tonight I think.

Fingers crossed for it just being a damp issue. Back tomorrow so will keep you posted and may be back for a couple more pointers.

Been searching on line for imperial size glands with no joy so far, any ideas if need be?

Cheers again

Sy

Imperial equivalents PDF has been posted on the forum a few times

 

[sythai]

Thanks again chaps for all your help - I've sorted it at last after a sleepless night worrying :icon14::icon14: :hurray::hurray:

At one point just tapped the edge of MI slightly, no visible damage but RCBO tripped, reset it and stayed in so thought nothing more of it (just a blip maybe?)

Maybe not... went back first this morning, located this area again now caked in plaster exposed fully/ cleaned off properly this time round - I had actually knicked the outer sheathing :90:

And then the plasterer had come along and finished it off - dead short across both phases and cpc.

Bit of luck on my side with this one really, there were 2 x MI's directly next to each other :

One going right back to the CU on the opposite side of the flat (concrete ceilings all the way!) and the other going about 3 meters away to the kitchen light switch.

Caught the kitchen light switch one, so no big deal to rewire.

Definitely a lesson learnt on this one.

Have a good weekend

Sy :smiley2:

 

[Lucien Nunes]

How did the plasterer damage the cable to cause a fault like that? Must have mangled it thoroughly and would have known about it. Or did you mean the moisture from the plaster got in through the original nick and it shorted in the resulting arcing?

 

[sythai]

Moisture fault ....