Made me jump!

[Mjward]

Moved into a new house and before I make a start on the serious renovation, thought I'd mount a TV so I have some evening entertainment.

Easy, the previous owners already had one up, just need to move along slightly for new pilot holes for the new bracket. Or so I thought.

Drilled first pilot hole, no issue.
Drilled second pilot hole and lights in room went out. (I didn't connect the two immediately as the microwave was on and this earlier triggered the RCBO).
Drilled third pilot hole and poof, bit of a spark, RCBO triggered again and told me something was not right.

The things that are alarming me are:

1) I've drilled a couple of inches horizontally from where previous mount was installed. Closer to a power socket but nowhere near above. Further away from a light switch and in no logical route of a cable run

2) the room lights are switching off when there was a power overload earlier on the sockets. Don't know why these would be on same RCBO.

This house is completely new to me less than a week ago so don't have a full understanding of the electrics but there s growing number of warning signs that something isn't right

 

[telectrix]

photos essential.and not just for a laff.

 

[Mjward]

photos essential.and not just for a laff.

original TV mount on far left.
My pilot holes in middle.
Sockets to right, there is a light switch out of shot to the left and down. If I wasn't bald I might have lost a few hairs!

 

[telectrix]

think youse bin unlucky. i would not expectcables to the left of that socket (unless it's a feed to the out of shot light switch which is norty as not fused down.).

time to get the hammer and chisel out.

 

[Mjward]

think youse bin unlucky. i would not expectcables to the left of that socket (unless it's a feed to the out of shot light switch which is norty as not fused down.).

time to get the hammer and chisel out.

lol literally browsing hammers as we speak! On the first day in we discovered the kitchen tap runs when you have a bath, and the kitchen ceiling leaks when the shower is on so this is definitely something I shouldn't have bought, but it is what it is.

 

[telectrix]

time to get your local wet-pants round.

 

[Mjward]

time to get your local wet-pants round.

100%. My DIY skills extend to running flow/return and fitting rads etc but not a whole house diagnosis. Now know why we got the place at such a good price ???

 

[static zap]

Carefully inspecting where the wires leave the socket.
... And learning the snake charming art of using a cable locator ...
( To discover the whole wall live , near the meter box outside )
Jammy gits miss the wire by 15mm every time.
(but once you have an audience wave good by to that-Skill)

Plastic pipes and no foil tracer... the wetpants story.

 

[brianmoooore]

Middle pilot hole is in a cable safe zone, where you shouldn't be drilling holes, but even so, I'd be surprised to encounter problems there.

 

[Mjward]

Middle pilot hole is in a cable safe zone, where you shouldn't be drilling holes, but even so, I'd be surprised to encounter problems there.

Roger that. I guess I'm surprised that for a CCU fitted in 2010 there seems to be a connection between the socket and the room light circuit (assuming I drilled into the socket wiring)

 

[brianmoooore]

Most CUs share the circuits between two RCDs, so nothing unusual in some of the lights going out if you damage a socket circuit.

 

[littlespark]

Anyone local to the OP want to drop in and have a look?

Bromley, according to profile.

 

[Darkwood]

To be fair the bracket holes are in zone and the original bracket was probably installed by those that knew exactly where the wires were, it's poor position of the original bracket tbh that led to this.

 

[nicebutdim]

Most CUs share the circuits between two RCDs, so nothing unusual in some of the lights going out if you damage a socket circuit.

OP states RCBO protection. Perhaps an image of CU might help.

Curious to know which hole caused the initial trip and which hole caused sparking.

 

[Dartlec]

Looks like I'm relatively local @Mjward so could arrange to pop in and have a look at some point - having a bit of a nightmare week, but might be able to arrange something.

What tripped - RCD that covers multiple circuits, or an RCBO just covering one circuit? You really need to locate the damaged cable in the wall and repair it before using the circuit in question again.

Are they stud walls? If so horizontal wiring is normally fairly rare if there's no socket to the left (though might be one on the reverse of that wall?)

 

[Mjward]

OP states RCBO protection. Perhaps an image of CU might help.

Curious to know which hole caused the initial trip and which hole caused sparking.

Looks like only one RCBO in fact and not part of circuit in question. I think most of you will enjoy a good laugh not only at the state of the CU but the labelling! It was the top right hole that caused initial trip, then the middle hole that caused the spark.

 

[Mjward]

Looks like I'm relatively local @Mjward so could arrange to pop in and have a look at some point - having a bit of a nightmare week, but might be able to arrange something.

What tripped - RCD that covers multiple circuits, or an RCBO just covering one circuit? You really need to locate the damaged cable in the wall and repair it before using the circuit in question again.

Are they stud walls? If so horizontal wiring is normally fairly rare if there's no socket to the left (though might be one on the reverse of that wall?)

Hello, very kind offer but unfortunately that is my old address, I'm up in West Yorkshire now if anyone is local to that area?

Plan is to chisel out the area today and assess the cable situation. Have now turned off the RCDs that cover the area in question (both lighting and power).

WIth regards to wall structure itself, this wall forms part of a fairly modern extension to a property from 1900, i.e. its attached to the old property's external wall. From knocking on the wall, there are definitely hollow voids but bizarrely where the original bracket was positioned sounds incredibly hollow vs where I was attempting to relocate to was solid as you like.

 

[brianmoooore]

D and C curve MCBs? 10A lighting circuits?

 

[telectrix]

it will be dot and dab. the hard parts are where the dabbers have splodged their fixative.

 

[DPG]

If something tripped when the 1st hole was drilled, but then you still got a spark when the 2nd hole was drilled then maybe you have drilled through two separate circuits? Or did you reset the tripped device after the 1st incident?

Loving the protection devices in the CU by the way. And the secret light!