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"Hello All",

I am trying to find out some information to give to a Friend who is investigating the cause of Damp in his Home`s wall and has seen that his neighbours have Armoured cables entering their building through just a Hole / `Slot` in the Brickwork under ground level [Not visible at present but this is known] and wondered if the Hole in the Brickwork could be the entry point for the Damp to travel along the wall and then up into the Party wall into His property.


These Armoured cables are the Electricity supplies to 2 Flats - from the Meters / Main Fuses which are installed in an External Meter box to the Consumer Unit within each Flat - the cables run down the wall into the ground and bend through a Hole `Slot` into the Building.


I happen to know / remember that no Ducting was used through the Hole / `Slot` in the Brickwork where the cables enter the other building and the Hole / `Slot` was never made good before the trench for the new Electricity supply was filled in - as I was working at my Friends Home installing a Heating system when these cables were installed next door - I remember seeing how the Cables were installed and thinking that they should have been Ducted through the wall with the Ducting sealed at least externally.

At the time I remember that the bends on the Armoured cable would not have allowed any form of Ducting to be installed which would have run the full thickness of the Wall - I assumed that this is why none was installed.


Now that I have been asked by my Friend for advice on whether this Hole below the ground could be causing the Damp to permeate along the walls and up into the Party wall I would like to be able to let my Friend / his Neighbours know what should have been done when the Armoured cables were installed through the wall - in terms of a Duct an sealing the Duct to prevent the ingress of Water from the ground both into the Brickwork and through the Duct - ?

I am sceptical that this is the cause of the Damp in His next door property because of the amount of time that has elapsed [Years] before this Damp problem exhibited itself - but He has recently spent a fair bit of Money on Professional Damp treatments of the Walls in the area of the Damp and adjacent to it which has not solved the problem.

The Hole adjacent to the Cable entry point has not been excavated yet so I cannot post any Photos but I can still visualise what was done when they were installed.



I would like to be able to let Him know exactly what should have been done - or what can now be done to try and rule out or solve the Damp problem by Sealing the underground entry point of these Armoured cables into next doors Building - obviously ideally by being able to just Seal up the Hole / `Slot` with something that will NOT affect the Armoured cable sheathing - is this possible ?

Unfortunately there would be no way to correctly install any Duct
around the Cables because of the way that they bend through the `Slot` / Hole in the Brickwork.

It is not going to be an option for an Electrician to disconnect these cables in order for them to be bent to allow a Duct to be installed [even IF there is enough slack within the Ground Floor Flat to pull back enough cable ?] because the People who now own the Flats are Pensioners who definitely cannot afford to pay for that.

As You can imagine my Friend does not want to pay for anything more than carefully digging a Hole adjacent the wall / Cable entry point and hopefully using something to Seal the Hole `Slot` in the Brickwork - which He can do Himself - will that be possible ?

I did not want to tell Him to just make good with Prompt Cement / Waterproof Cement or even Sand & Cement Mortar in case this would be corrosive to the exterior sheathing of the Armoured cable - ?

Obviously because the Hole is under ground whatever is used would have to be Waterproof.


I would really appreciate your Help and Advice on this Please.


Regards,


Chris
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

I won't be checking up on you as it makes no difference to me :) and because you sound genuine :)

I did read the entire post prior to initially replying and but i am struggling to imagine a situation where you can't fit any ducting at all around, if there is a bend/bends why not get some flexible ducting as its only to stop the concrete touching the sheath? How deep would the concrete be, wouldn't even a foot of ducting suffice?

I am sticking with having to dig it up to have a look, there's noway of knowing if the damp is coming from there without digging it up really!

Good luck


"Hello again Tidy Max",

The reason why any type of Ducting which would span the thickness of the wall cannot be retrofitted to the Armoured cables is because they are clipped down the external wall and below ground level they bend into a `Slotted Hole` [vertically slotted] which was cut into the Brickwork at an angle - the cables bend into the `Slot` but actually penetrate the Brickwork lower down - there is NOT a Hole straight through the Brickwork - it is angled downwards.

The Ground is Clay - there is no concrete - just the entry Hole / `Slot` in the external wall - this needs to be sealed up with an appropriate Sealing product which will not affect the Armoured cable sheathing.

Although I did mention `Sand & Cement Mortar` in my original post - this would NOT be Waterproof - so not suitable to prevent Damp from the ground entering the Brickwork.

Thanks again for your interest and comments.

Regards,

Chris
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

Definitely sounds bad practice if I'm picturing it right. It's funnelling water into the outer face of the wall. Still like a photo though. Daz
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

If your cable is entering through an odd shaped hole then use duct seal putty something like this. You also can use something called non-drip tape/cork tape which is a bitumen and butyl rubber tape that can be wrapped around the cable and molded into the hole.
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

I may be missing something here, but could you not fill around the cable with silicon? I may be on the wrong track - it's difficult to picture. Can you post a photo? Daz

"Hello Daz",

I did mention that the Hole adjacent the cable entry point has not been excavated yet so cannot post a Photo.

I am remembering all of what I have described.

This is just a Hole / `Slotted Hole` [slotted downwards] with 2 Armoured cables going through it -


The Hole is not just big enough to allow the 2 cables to pass through - from memory I think that it is least 150mm wide - so there will be some `filling in` to be done with pieces of Brick - perhaps then a `Mastic` type sealant would be appropriate - but possibly something better than Silicone ?

Thanks again,

Regards,

Chris
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

Better than silicon? I'd have thought it would do the job admirably. Daz
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

Although I did mention `Sand & Cement Mortar` in my original post - this would NOT be Waterproof - so not suitable to prevent Damp from the ground entering the Brickwork.

I doubt if adding a proprietary waterproofing agent to the mortar would compromise the cable.

Edit:
http://www.watco.co.uk/sbr-waterproof-additive.html
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

For filling the hole, I can't see a problem with an ordinary sand/cement mortar mix. The armoured cable will almost certainly have a PVC sheath, so no problem. Whatever you do, don't fill the hole with expanding foam, as it's a good thermal insulator, which will affect the current carrying capacity of the cables.


Expanding foam certainly is a "good thermal insulator" BUT here we are talking about a wall which will probably be one foot thick through which this cable is passing.

Assuming the expanding foam expands all the way through from one side of the wall to the other, we have a one foot length of cable "thermally insulated" by the foam.

Assuming this is a "domestic property" is there ever going to be any likelihood of sufficient load passing through this cable to even slightly warm it and if it does, would the remaining umpteen feet of cable buried in the ground not be sufficient to dissipate this heat??

Am I being over simplistic or are you overthinking this issue?

I don't know. ......... I'm just a plumber who "knows a bit about electrics"!! ;)
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

For filling the hole, I can't see a problem with an ordinary sand/cement mortar mix. The armoured cable will almost certainly have a PVC sheath, so no problem. Whatever you do, don't fill the hole with expanding foam, as it's a good thermal insulator, which will affect the current carrying capacity of the cables.

"Hello HandySparks",

Sorry for not replying to You sooner.


Thanks very much for the information about he Expanding Foam - something like this point being raised is exactly why I raised this question on here.

Because I had remembered that the Hole / `Slot` was much bigger than the 2 Cables my Friend had mentioned using Expanding Foam to fill most of the Hole and asked about using Waterproof Cement on the last 25-30mm.

Thanks very much for letting e know why NOT to use that !

Regards,

Chris
 
Last edited:
Is the hole under dpc, is there void under floor, unless it's gone through dpc layer damp shouldn't be rising into the wall. How far away is hole from damp area. Think more likely condensation problem, it generally happens in corners.
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

Is the hole under dpc, is there void under floor, unless it's gone through dpc layer damp shouldn't be rising into the wall. How far away is hole from damp area. Think more likely condensation problem, it generally happens in corners.

I thought the cables were coming DOWN the wall and curving into the building. Is the water not coming down the cables? Am I being thick? Will it ever end? Daz
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

Expanding foam certainly is a "good thermal insulator" BUT here we are talking about a wall which will probably be one foot thick through which this cable is passing.

Assuming the expanding foam expands all the way through from one side of the wall to the other, we have a one foot length of cable "thermally insulated" by the foam.

Assuming this is a "domestic property" is there ever going to be any likelihood of sufficient load passing through this cable to even slightly warm it and if it does, would the remaining umpteen feet of cable buried in the ground not be sufficient to dissipate this heat??

Am I being over simplistic or are you overthinking this issue?

I don't know. ......... I'm just a plumber who "knows a bit about electrics"!! ;)

"Hello Geordie Spark",

I did not see your message as I was writing my reply to HandySparks.

Although I do NOT doubt your Technical knowledge about this I am now reluctant to advise my Friend to go ahead with Expanding Foam and Waterproof Cement - `Just in case` of a problem caused the Insulating properties of the Expanding Foam ?

From memory think that these Armoured cable are touching each other as they go through the Hole - take it hat as they are `Armoured` / well insulated this would mean that there would not be any problem associated with that ?

Regards,

Chris
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

I thought the cables were coming DOWN the wall and curving into the building. Is the water not coming down the cables? Am I being thick? Will it ever end? Daz

"Hello again",

The Cables are clipped down the wall - underneath a Wall / Surface mounted Meter box.

Water could be running down the cables into the Brickwork - but this would just be Rain falling onto the ground next to the cables - and the Hole would still need to be correctly sealed.

The Ground level /gradient does not cause surface water to run towards the Cables.

Regards,

Chris
 
Last edited:

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