Notches or Holes, clip or not to clip?

[FatAlan]

Appart from the building regs specification on the size and positioning of notches and holes in joists is there a best practice on what to use? Is it just the case that notches are used in place of holes due to the cable positioning being outside that prescribed for holes. Are there any issues with not clipping cables under floor boards? I say this as when for instance you install down lights it seems prudent to have a fair bit of slack left for future work / fittings etc.

 

[Squid]

and bond all the floorboard nails.........

 

[Generator]

I'll ignore the sarcasm Pete (seen far worse on here! ). I was thinking about the similarity to metal capping, which I think is now supposed to be earthed ( certainly in 522.6.6 outside of a 'zone' ). Earthing of concealed metallic cable covering is only common sense in a house - regs or not. Everything has to be hidden - even sockets.

I've had experience of this in my existing house AND the previous one! I got a good belt when I touched the end of a wall capping under the floorboards - good job I didn't have the other hand on the CH pipes! Turned out the Dado Rail in the room below was nailed exactly over the capped ring main cables, vertically above a socket! - I was wondering why that circuit had a lowish IR! - 5Mohm.
In the previous house the wall in the hall had a faint 'rough ' feeling in the area above a socket - that circuit also had a 'lowish' IR , guess what? - nail through the capping, fixing the Dado Rail!
In both cases the capping can remain live for years - and it wouldn't trip an RCD either. If the capping is earthed, a penetrating nail/screw/drill would trip an MCB if it touched a live, or at least an RCD (hopefully).

So, hence my comment about the protection plate - which wouldn't be required if the joist were to be drilled! - and no, I wouldn't earth radiators (which are connected to earthed pipework), nails, screws,
or metallic windows ( unless they are motorised).

Better keep my head down now!
John.

 

[Generator]

I'll ignore the sarcasm Pete (seen far worse on here! ). I was thinking about the similarity to metal capping, which I think is now supposed to be earthed ( certainly in 522.6.6 outside of a 'zone' ). Earthing of concealed metallic cable covering is only common sense in a house - regs or not. Everything has to be hidden - even sockets.

I've had experience of this in my existing house AND the previous one! I got a good belt when I touched the end of a wall capping under the floorboards - good job I didn't have the other hand on the CH pipes! Turned out the Dado Rail in the room below was nailed exactly over the capped ring main cables, vertically above a socket! - I was wondering why that circuit had a lowish IR! - 5Mohm.
In the previous house the wall in the hall had a faint 'rough ' feeling in the area above a socket - that circuit also had a 'lowish' IR , guess what? - nail through the capping, fixing the Dado Rail!
In both cases the capping can remain live for years - and it wouldn't trip an RCD either. If the capping is earthed, a penetrating nail/screw/drill would trip an MCB if it touched a live, or at least an RCD (hopefully).

So, hence my comment about the protection plate - which wouldn't be required if the joist were to be drilled! - and no, I wouldn't earth radiators (which are connected to earthed pipework), nails, screws,
or metallic windows ( unless they are motorised).

Better keep my head down now!
John.

 

[pirate]

I have bonding to my cutlery drawer, so none of my forks are risky when i chuck them in randomly...but, I'm puzzled about diversity...does the number of adjoining knives and spoons affect the situation were I to accidentally switch the whole drawer on at once, given the lighting in said drawer is tee'd off the cooker-hood...and the drawer slides are only on a 6mm cpc?

 

[pirate]

and on a serious note, in my last house I removed an old carpet in a bedroom and saw a slightly raised nail-head...it was live... and had been for years probably...neatly placed into a cable supplying the nearest socket...it was my daughters bedroom, and she was 1 at the time, crawling around on all-fours..
naturally, not being a spark, I put a thicker carpet down!

 

[DPG]

I'll ignore the sarcasm Pete (seen far worse on here! ). and no, I wouldn't earth radiators (which are connected to earthed pipework), nails, screws,
or metallic windows ( unless they are motorised).
John.

What about if they are fed with plastic pipe, as most are these days?

 

[Generator]

dunno - what's the conductivity of dosed central heating water?

 

[GB.Kayak]

Hello GB.Kayak,

I found out about `Deafening` about 27 years ago when my Business partner and I went up to Edinburgh to carry out installation of a very large `Domestic` Heating system ...

Thanks Chris,

I ... unlike some others on here don't mind long yet informative posts indeed I enjoy reading them. About 2 years ago I suggested that there should be a specific area on the forum to address the installation 'issues' of 'historic' and 'traditional' or vernacular buildings. They are not best treated with chipboard, dry lining ... some of the later ones were the 'original' dry lined buildings, gypsum based plaster, cement, silicone sealant or polyurethane 'spray' foam! The knowledge of their construction, availability of the materials from which they were constructed and tradespeople skilled in traditional materials and approaches are all serious challenges in maintaining such buildings. Any knowledge that can be garnered from often retired tradesmen should by collected and recorded for those of us who wish to follow in their 'footsteps'!

I imagine that those floorboards were at least 1 1/8 " thick ... ours certainly are. They are slow grown, likely to be old growth Nordic redwood (?), of ~ 1876 vintage with almost too many rings per inch to count with the naked eye ... I make it about 28!

... here is a sample ...

It is a tragedy to have to cut timber of that quality out to eradicate dry rot!

Yours Aye

GB

 

[chris murphy]

Thanks Chris,

I ... unlike some others on here don't mind long yet informative posts indeed I enjoy reading them. About 2 years ago I suggested that there should be a specific area on the forum to address the installation 'issues' of 'historic' and 'traditional' or vernacular buildings. They are not best treated with chipboard, dry lining ... some of the later ones were the 'original' dry lined buildings, gypsum based plaster, cement, silicone sealant or polyurethane 'spray' foam! The knowledge of their construction, availability of the materials from which they were constructed and tradespeople skilled in traditional materials and approaches are all serious challenges in maintaining such buildings. Any knowledge that can be garnered from often retired tradesmen should by collected and recorded for those of us who wish to follow in their 'footsteps'!

I imagine that those floorboards were at least 1 1/8 " thick ... ours certainly are. They are slow grown, likely to be old growth Nordic redwood (?), of ~ 1876 vintage with almost too many rings per inch to count with the naked eye ... I make it about 28!

... here is a sample ...
View attachment 40553
It is a tragedy to have to cut timber of that quality out to eradicate dry rot!

Yours Aye

GB

Hello again GB.Kayak,

Thanks for your reply,

The Edinburgh House that I described really was a great property - full of `Period Fixtures & Fittings` regarding - Ceiling Roses and Cornices - really elaborate Marble Fireplaces - 15" high Skirting Boards - elaborate / `elegant` Staircase - mosaic tiling to entrance Hall etc.

If I am remembering correctly built somewhere around 1850 - the Oak Floorboards measured 12" x 1" imperial and there was some talk that the timber had come from a redundant Wooden Sailing Ship that the original Homeowner had owned and that he had it stripped down and machined into Floorboards to be supplied to the House Builder so that he would not only save quite a lot of money but would make good use of the redundant Ship.

The adjacent Houses did not have the same Floorboards which seemed to confirm that at least the original Homeowner or Builder had specified larger boards.

On the Electrical works - something that I noticed while working at the House was regarding the making good of wall chases for wall lights wiring was that the Electricians used `Fire Cement` to fill the chases - they made a perfect job of filling the chases to a `Decorating finish` - the Fire Cement / Brush / Water / Filling knife created a very smooth finish.

Although Fire Cement has never been `cheap` it must have been cost effective for them regarding being able to leave a `Decorating Finish` without other forms of Plastering / Filling.

Some of the Wallpaper on walls where these chases were was either a very expensive Silk based wallcovering or an expensive printed Vinyl - the Decorators said that these `Papers` would show `every spot` even after the Lining paper - they had various problems with the old plaster on the walls - but never with the filling of the wall chases [Fire Cement] done by the Electricians.

Just in case this is ever read by any `Non Trades` people - the Fire Cement that I refer to is usually used to seal around Gas Fire Closure plates etc. and was used on `Non Asbestos Cement Flue Pipe` socket joints some years ago - before Metal Flue Systems were manufactured.

I cannot imagine that Fire Cement has changed much in the last 27 Years - however please don`t take this as a `recommendation` from me as I don`t know whether it would have any detrimental effect on the Cables ?

At the time the Electricians said that it would NOT - however I wondered if they actually KNEW that ?

Regards,

Chris

 

[DPG]

If you two keep it up with these long posts the forum will need new servers!

Only kidding - it's nice to hear about these old methods etc. No offence intended.

 

[chris murphy]

Hello All,

Having written about the use of Fire Cement to fill cable chases for wall lights and stating that I did not know whether it would be detrimental to the Electrical Cables Insulation I decided [27 years after asking the Edinburgh Electricians ] to look at the `Safety Data Sheet` for KOS Fire Cement which is a well known brand - here is a link to the Data Sheet:

https://www.everbuild.co.uk/wp-content/uploads/2017/08/Everbuild KOS Fire Cement SDS v4.pdf

I would guess that this paragraph is probably of some significance regarding possible degradation of the PVC Cable Insulation:

Here is a quote regarding using Rubber Gloves while using this particular Fire Cement:

QUOTE:

Suitable for short time use or protection against splashes: Butyl rubber/nitrile rubber gloves (0,4 mm), Contaminated gloves should be removed. Suitable for permanent exposure: Viton gloves (0.4 mm), breakthrough time >30 min.

I have highlighted the text - however I am not sure what this paragraph means:

QUOTE: Suitable for permanent exposure: Viton gloves (0.4 mm), breakthrough time >30 min. END OF QUOTE.

`Permanent exposure` and `breakthrough time > 30 min` seem contradictory to me - ?


Personally the details about Rubber Gloves would be enough to make me think that Fire Cement should NOT be used to fill Electrical cable wall chases !

That Edinburgh House was lived in by my very good Friend and his Family for about 8 years and nothing `came to light` [excuse the unintended pun] regarding any problems with the wall light cables - but perhaps any degradation of the cable insulation can be a slower process that those 8 years ?

I know that Members will probably think `what is he going on about ?` - but as I described Fire Cement being used to fill wall chases at the Edinburgh House [27 years ago] that I wrote about I wanted to add this just in case a future reader / DIY person decided to use it and it caused problems with the cable insulation.

Regards,

Chris

 

[FatAlan]

and bond all the floorboard nails.........

I have all my hammers and screw drivers connected to earthing leads just in case

 

[FatAlan]

I'll ignore the sarcasm Pete (seen far worse on here! ). I was thinking about the similarity to metal capping, which I think is now supposed to be earthed ( certainly in 522.6.6 outside of a 'zone' ). Earthing of concealed metallic cable covering is only common sense in a house - regs or not. Everything has to be hidden - even sockets.

I've had experience of this in my existing house AND the previous one! I got a good belt when I touched the end of a wall capping under the floorboards - good job I didn't have the other hand on the CH pipes! Turned out the Dado Rail in the room below was nailed exactly over the capped ring main cables, vertically above a socket! - I was wondering why that circuit had a lowish IR! - 5Mohm.
In the previous house the wall in the hall had a faint 'rough ' feeling in the area above a socket - that circuit also had a 'lowish' IR , guess what? - nail through the capping, fixing the Dado Rail!
In both cases the capping can remain live for years - and it wouldn't trip an RCD either. If the capping is earthed, a penetrating nail/screw/drill would trip an MCB if it touched a live, or at least an RCD (hopefully).

So, hence my comment about the protection plate - which wouldn't be required if the joist were to be drilled! - and no, I wouldn't earth radiators (which are connected to earthed pipework), nails, screws,
or metallic windows ( unless they are motorised).

Better keep my head down now!
John.

Good point. The metal plates are more substantial than they look. You would be going some to drive a nail through one and a wood bit would get nowhere. Surprised there isn’t some sort of insulated Kevlar style cable/notch gland. Quick, I must get down the patent office.

 

[Squid]

I have bonding to my cutlery drawer, so none of my forks are risky when i chuck them in randomly...but, I'm puzzled about diversity...does the number of adjoining knives and spoons affect the situation were I to accidentally switch the whole drawer on at once, given the lighting in said drawer is tee'd off the cooker-hood...and the drawer slides are only on a 6mm cpc?

Are they gender neutral cutlery and ambidextrous friendly

 

[Pete E]

Hello All,

Having written about the use of Fire Cement to fill cable chases for wall lights and stating that I did not know whether it would be detrimental to the Electrical Cables Insulation I decided [27 years after asking the Edinburgh Electricians ] to look at the `Safety Data Sheet` for KOS Fire Cement which is a well known brand - here is a link to the Data Sheet:

https://www.everbuild.co.uk/wp-content/uploads/2017/08/Everbuild KOS Fire Cement SDS v4.pdf

I would guess that this paragraph is probably of some significance regarding possible degradation of the PVC Cable Insulation:

Here is a quote regarding using Rubber Gloves while using this particular Fire Cement:

QUOTE:

Suitable for short time use or protection against splashes: Butyl rubber/nitrile rubber gloves (0,4 mm), Contaminated gloves should be removed. Suitable for permanent exposure: Viton gloves (0.4 mm), breakthrough time >30 min.

I have highlighted the text - however I am not sure what this paragraph means:

QUOTE: Suitable for permanent exposure: Viton gloves (0.4 mm), breakthrough time >30 min. END OF QUOTE.

`Permanent exposure` and `breakthrough time > 30 min` seem contradictory to me - ?


Personally the details about Rubber Gloves would be enough to make me think that Fire Cement should NOT be used to fill Electrical cable wall chases !

That Edinburgh House was lived in by my very good Friend and his Family for about 8 years and nothing `came to light` [excuse the unintended pun] regarding any problems with the wall light cables - but perhaps any degradation of the cable insulation can be a slower process that those 8 years ?

I know that Members will probably think `what is he going on about ?` - but as I described Fire Cement being used to fill wall chases at the Edinburgh House [27 years ago] that I wrote about I wanted to add this just in case a future reader / DIY person decided to use it and it caused problems with the cable insulation.

Regards,

Chris

I would think ( and its just a hunch) that the "risk of reaction" would be greatest when the fire cement was wet, but reduce greatly once it was it was dry?

My previous home had a wood burner so I've used it quite a bit in its correct capacity but would never have thought of using it instead of polyfilla! Interesting thread!