Armoured cable into building below ground - how should hole have been ducted / sealed

[HandySparks]

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

 

[Geordie Spark]

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"!!

 

[chris murphy]

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

 

[Newbyspark]

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.

 

[DPG]

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

 

[chris murphy]

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

 

[DPG]

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

This is gonna go on and on this one. Daz

 

[Geordie Spark]

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

This is gonna go on and on this one. Daz

It's going to put anything written by Tolstoy to shame.

 

[Silly Sausage]

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

Chris, we need pictures of this cable penetration!

 

[chris murphy]

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

 

[Guest55]

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.

 

[chris murphy]

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

 

[Guest55]

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

"with" "either" "silicon" "or" "cement" "for" "below" "ground" "entry" "points"
"regards"

";-)"

 

[chris murphy]

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

 

[Silly Sausage]

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

"and" "it" "won't" "cure" "the" "damp" "problem" "!!!"
"Cheers!"

 

[Geordie Spark]

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:

 

[chris murphy]

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

 

[HandySparks]

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.

 

[Geordie Spark]

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.

 

[Silly Sausage]

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

Re: Insulating foam, cable sounds like it's water cooled anyway.