Extremely loud bang near fusebox.

[ebee]

I investigate reports of such a bang a few years back, after the customer told me where he thought the noise came from I looked under floorboards.

T & E hanging down under the floor and laying on damp soil. Pinhole in cable (might have been there since installation some years previous).
I deducted that dirty water had penertrated, caused a short, rapid heating of cable caused the "bang" and cleared the fault at the same time and ready to start the procedure again hours later the time period dependant upon the actual dampness of the soil at the time.

Renewed cable,clipped it up and clipped up all other nearby cables hanging in a similar fashion.
The problem never returned over ten plus years compared to between once to six times a day.
So I recckoned probably sorted.
(Rewireable 30A fuses and no RCD).

 

[jj4091]

I investigate reports of such a bang a few years back, after the customer told me where he thought the noise came from I looked under floorboards.

T & E hanging down under the floor and laying on damp soil. Pinhole in cable (might have been there since installation some years previous).
I deducted that dirty water had penertrated, caused a short, rapid heating of cable caused the "bang" and cleared the fault at the same time and ready to start the procedure again hours later the time period dependant upon the actual dampness of the soil at the time.

Renewed cable,clipped it up and clipped up all other nearby cables hanging in a similar fashion.
The problem never returned over ten plus years compared to between once to six times a day.
So I recckoned probably sorted.
(Rewireable 30A fuses and no RCD).

I guess there must be a scientific reason why that sort of thing happens, sudden ionizeation of the surrounding air perhaps, just like why a fuse bangs when it fails sometimes. A bit above my paygrade though.

 

[sorryf]

Thank you all.

 

[sorryf]

I investigate reports of such a bang a few years back, after the customer told me where he thought the noise came from I looked under floorboards.

T & E hanging down under the floor and laying on damp soil. Pinhole in cable (might have been there since installation some years previous).
I deducted that dirty water had penertrated, caused a short, rapid heating of cable caused the "bang" and cleared the fault at the same time and ready to start the procedure again hours later the time period dependant upon the actual dampness of the soil at the time.

Renewed cable,clipped it up and clipped up all other nearby cables hanging in a similar fashion.
The problem never returned over ten plus years compared to between once to six times a day.
So I recckoned probably sorted.
(Rewireable 30A fuses and no RCD).

This sounds exactly like my problem. You've reminded me that the bang did sound like it was from under our floorboards - before I went and convinced myself differently. Thank you very much.

We have an electrician coming tomorrow afternoon, I will report back then.

 

[securespark]

I investigate reports of such a bang a few years back, after the customer told me where he thought the noise came from I looked under floorboards.

T & E hanging down under the floor and laying on damp soil. Pinhole in cable (might have been there since installation some years previous).
I deducted that dirty water had penertrated, caused a short, rapid heating of cable caused the "bang" and cleared the fault at the same time and ready to start the procedure again hours later the time period dependant upon the actual dampness of the soil at the time.

Renewed cable,clipped it up and clipped up all other nearby cables hanging in a similar fashion.
The problem never returned over ten plus years compared to between once to six times a day.
So I recckoned probably sorted.
(Rewireable 30A fuses and no RCD).

I need to draw ebee's experience to JohnW2's attention!

Here was my situation:
Starts at #14.

S

Thread 'Line -CPC Insulation resistance'

31 Jan 2020

Could I just ask for some advice , as I am doubting myself..., or my test results

Dual RCD board, in an unoccupied house, (between moves)

Recent rewire, probably a year old - No installation certificates.

Doing insulation resistance tests.
Global test, gives poor readings, so I separate all the lives , neutrals,
and test to cpc - still the same so I separate cpcs , and still the same.

One side of the RCD, these circuits test around the 200 M ohms. For a new install I would expect off the range. (Megger 1741, so 999)

The other side, Im getting 0.2 Mohms on every circuit.
This is with...

• studentspark
• Replies: 26
• Forum: Electrics UK