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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

stop guessing and just get a damp proof contractor / building surveyor to pin point the problem instead of randomly digging stuff up.

and if the damp course is intact and active , theres no way a piddling cable hole is going to introduce rising damp above a ventilated sub-floor.

and an few inches of cement / silicon / expanding foam isnt going to make 1 iota of difference to the operating temp of a swa.
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

"Hello Gentlemen",

To `Simplify this as I should have done originally:

I JUST need to know:

How do You Seal an underground Armoured cable entry Hole in Brickwork to maintain a Waterproof structure around the Cables ?

Regards,

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

stop guessing and just get a damp proof contractor / building surveyor to pin point the problem instead of randomly digging stuff up.

and if the damp course is intact and active , theres no way a piddling cable hole is going to introduce rising damp above a ventilated sub-floor.

and an few inches of cement / silicon / expanding foam isnt going to make 1 iota of difference to the operating temp of a swa.

"Hello biff55",

I am NOT Guessing anything - I have been asked by my Friend HOW to SEAL UP the Armoured cable underground entry Hole through Brickwork - I have asked the Electrical Experts on here.

A `Damp Proof Contractor` is VERY unlikely to know the Correct method !

The Building in question des NOT have a Damp Proof Course - this is quite `normal` in Buildings around some areas of London which are built on Clay.


Thanks for your opinion about the Expanding Foam etc.

Regards,


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

"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

Hi Chris ! :)

My reply to you was not based on "Technical Knowledge" - it was based on Geordie instinct and common sense.

We're not talking about an industrial installation or even a commercial installation here are we so the current being drawn through the cable will be relatively light - even with the electric cooker working so I doubt if the cable will get anywhere near warm and if it does, surely the remainder of the cable that isn't covered by the foam will dissipate the little bit of warmth generated. It isn't all going to sit in that same spot all day is it? If you somehow manage to put a lump of hot water in the middy of a 3 meter length of 15mm pipe does that heat stay in that one place - or does it spread towards each end of the pipe reducing the temperature as it goes?

OK - I admit that in the case of the pipe it will progressively cool while the cable won't, because it has electricery passing through it, but at the same time I really don't think you're going to get things all that hot in a domestic situation. A factory or large warehouse situation where you're pulling lots of amps through the thing I think could be a different kettle of horses

NOT that it matters, but are you sure these cables are armoured (S W A) and not Split Concentric which look similar but don't have the Steel Wire Armour built into them?

If you wanted to sleeve this BTW, how about a piece of plastic waste ( 40mm maybe? ) split along it's length so you can open it enough to spring it over the cables? I'm guessing as I can't see the job from here !! :sailor:
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

DUPLICATED POST DELETED


I am having problems typing my messages on the Forum - this somehow posted exactly the same reply to Tidy Max as I had submitted some time ago.

I cannot type correctly at present - it is as if my Keyboard keys are only working intermitantly - and randomly intermitantly !

I will try and answer a couple of more replies but if I `Disappear` Tonight it will be because of this Typing problem.

Thanks to all for their responses - including the messages that contain `Digs` at my unusual / incorrect use of some punctuation marks !

Regards,


Chris
 
Last edited:
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"!! ;)

Hi Geordie,
Yes, maybe I'm being overly pessimistic, but without knowing the size of cable and its loading, my inclination is to play it safe. After all, the standard de-rating factor for 200mm of insulation is 0.63 and for 400mm, it's 0.51 (no tabulated figure for 300mm). So, the reduction in current carrying capacity is not trivial.
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

Hi Geordie,
Yes, maybe I'm being overly pessimistic, but without knowing the size of cable and its loading, my inclination is to play it safe. After all, the standard de-rating factor for 200mm of insulation is 0.63 and for 400mm, it's 0.51 (no tabulated figure for 300mm). So, the reduction in current carrying capacity is not trivial.

Agreed ..... without seeing it it's a guessing game really.
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

cement, butyle mastic, CT1, proper long life outdoor rated silicon... anything along those lines really, just get the surface clean first.

I'd think there is a potential that this is the cause, and it could have taken this long to show up if the water table has risen / there's been a particularly wet period, or a leaking drain etc.

Often supposedly solid walls actually have a narrow cavity / rubble filled cavity before internal blockwork / cinder block, and any water can run along the cavity, so it's possible that water entering in one place can cause issues further down the wall.

Best to rule it out anyway for the sake of half an hours digging and a couple of quid's worth of sealant.

I'd still rate it as far more likely that the damp is actually down to condensation on a cold spot on the wall if it's not from a leaking drainpipe etc, as even if it did leak in in that way during exceptional rain, I doubt it's going to do it often enough to end up causing damp internally.
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

DUPLICATED POST DELETED


I am having problems typing my messages on the Forum - this somehow posted exactly the same reply to Tidy Max as I had submitted some time ago.

I cannot type correctly at present - it is as if my Keyboard keys are only working intermitantly - and randomly intermitantly !

I will try and answer a couple of more replies but if I `Disappear` Tonight it will be because of this Typing problem.

Thanks to all for their responses - including the messages that contain `Digs` at my unusual / incorrect use of some punctuation marks !

Regards,


Chris

I'm clutching at straws here Chris, but is this any good? Waterproofing & Tanking Products - Damp, Waterproofing, Woodworm, Timber Treatment, Wood Preservative
 
Re: Armoured cable into building below ground - how should hole have been ducted / se

Hi Chris ! :)

My reply to you was not based on "Technical Knowledge" - it was based on Geordie instinct and common sense.

We're not talking about an industrial installation or even a commercial installation here are we so the current being drawn through the cable will be relatively light - even with the electric cooker working so I doubt if the cable will get anywhere near warm and if it does, surely the remainder of the cable that isn't covered by the foam will dissipate the little bit of warmth generated. It isn't all going to sit in that same spot all day is it? If you somehow manage to put a lump of hot water in the middy of a 3 meter length of 15mm pipe does that heat stay in that one place - or does it spread towards each end of the pipe reducing the temperature as it goes?

OK - I admit that in the case of the pipe it will progressively cool while the cable won't, because it has electricery passing through it, but at the same time I really don't think you're going to get things all that hot in a domestic situation. A factory or large warehouse situation where you're pulling lots of amps through the thing I think could be a different kettle of horses

NOT that it matters, but are you sure these cables are armoured (S W A) and not Split Concentric which look similar but don't have the Steel Wire Armour built into them?

If you wanted to sleeve this BTW, how about a piece of plastic waste ( 40mm maybe? ) split along it's length so you can open it enough to spring it over the cables? I'm guessing as I can't see the job from here !! :sailor:


"Hello Geordie Spark",

Thanks very much for your message and the details about the dissipation of any Heat that might ever be generated on a Armoured cable that has Expanded Foam around it.

Regarding trying to Sleeve these cables - Because of the way that the cables have been bent through the `Slotted Hole` it is not possible to reto-fit anything like a split pipe around them.

Not only are they bent at about a 135 degree angle downwards through the Slot / Hole but one is on top of the other as they penetrate into the Building.

The `Slotted Hole` was cut into the Brickwork at about a 135 degree angle - with only the penetration Hole to inside being horizontal.


I am calling the cables `Armoured` as they are Black and from memory about 30mm in diameter - You could be correct that they are some other type of cable - but they are clipped to the outside of the Building so I THOUGHT they would have to be Armoured [?]


When they were installed the Meters / Main Fuses were connected to them by the Electricity Suppliers Electricians so they were the correct cables for that outside location.


Thanks for your suggestions - as always I appreciate your Help and Advice.

Regards,


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

"Hello Geordie Spark",

Thanks very much for your message and the details about the dissipation of any Heat that might ever be generated on a Armoured cable that has Expanded Foam around it.

Regarding trying to Sleeve these cables - Because of the way that the cables have been bent through the `Slotted Hole` it is not possible to reto-fit anything like a split pipe around them.

Not only are they bent at about a 135 degree angle downwards through the Slot / Hole but one is on top of the other as they penetrate into the Building.

I am calling the cables `Armoured` as they are Black and from memory about 30mm in diameter - You could be correct that they are some other type of cable - but they are clipped to the outside of the Building so I THOUGHT they would have to be Armoured [?]


When they were installed the Meters / Main Fuses were connected to them by the Electricity Suppliers Electricians so they were the correct cables for that outside location.


Thanks for your suggestions - as always I appreciate your Help and Advice.

Regards,


Chris


No problem Chris.

Bloody Hell though ... those cables are a lot bigger than I was thinking - I was thinking of the one that comes into my house which is like a bit of 15mm Speedfit pipe !!

If they are as big as you say, it throws most of what I have said straight out of the window.

Anyway, It was good to meet up with you again.
 
Re: Armoured cable into building below ground - how should hole have been ducted / se



"Hello again Geordie Spark",

I don`t think that there would be too much of a problem getting Waterproof Cement - the Damp Proofing Contractor should be able to either supply this or recommend what to buy - BUT I needed to KNOW that this would not be corrosive to the Cable sheathing and would adhere to the sheathing itself before I can advise my Friend correctly

I felt that it would not be appropriate to apply Tape around the Cables where a Cement product would be contacting them as this would be a possible Water ingress point - ?


Thanks again.

Regards,

Chris
 

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