Cables in cavities (Sorry!)

[FUSEServices]

Hi all.

Want to get this clear once and for all!!

Can you run unprotected cables through or along or down a cavity?

I have seen what the polystyrene stuff does to cables, also replaced someones alarm cable today that had been munched on inside the cavity!!

Sorry to start this one off again - what's the opinion? I ALWAYS install 20mm conduit as I have done today!

Kev

Okay - no one is biting here, so I'll cut to the chase. Please have a look at this site and the video that's on it - unbelievable if you ask me, but what's the general opinion out there?

MagnaMole - Talpa Products Ltd - Home

 

[Myles]

If drilling through for external lights / adaptable box / etc I will put a piece of 20mm plastic conduit through the cavity also. Did exactly this yesterday in fact

 

[FUSEServices]

Good lad!

Here Here.

The rats go into cavities - even them with rockwool, just like in the video.

And polystyrene beads EAT cable!

Never take a chance

 

[sparks1234]

Good lad!

Here Here.

The rats go into cavities - even them with rockwool, just like in the video.

And polystyrene beads EAT cable!

Never take a chance

I have only ever seen it the other way round, the cable eats the poly

 

[Des 56]

Buildings expert
If cables are in a cavity straight through,they probably shouldn't be there ,damp tracking under fed gymnastic rodents then theres rot or chemical deterioration of insulation

We have no choice says the spokesman for common sense
How else can the cables see the big wide world yonder

Buildings man
If they are wired through the cavity they should be supported, conduit or no conduit , they cant be supported after they are build so no,no,no

Common sense man
They are not really heavy items and little or no movement,so the stresses on them may be minimum and you have less chance of drilling the little darlings,so I'll get them in before he can see

Its all a bit of use your own jugeemnt and live with it as per most electrical work
The danger issues are sorted by the system protection,so i see it as more of a structural question than electrical

 

[FUSEServices]

So what if the insulation deteriorates, and damp bridges L & N, no rcd protection and on a 32A fuse???

Your telling me that the fuse will trip before a fire starts - I don't think so mate!

Acrobatic rodents? ? ? Yep they sure are, have you not seen any??

NO problem with lack of support, that's not going to happen in a domestic situation?

I guess you run cables straight through then?

 

[cbw]

If its going outside it will be rcd protected so as Des says whats the problem?

I like the idea of a bit of oval conduit running through, will use that next week for an outside socket I need to get done!

 

[FUSEServices]

Of course on a new installation.

What if you were running say an alarm cable, or an aerial coax - I admit no danger, but still bad practice?

 

[cbw]

Thing is, walking along any terace street each and every house(Thousands) all have coax drilled in at least 2 places, what is the alternative?

 

[FUSEServices]

Small bore copper pipe, Plastic conduit, Expanding foam injection, etc

 

[Myles]

Alarm / coax....yeah if its good enough for NTL then crack on!

One could argue it would be practical to put in a drip loop if being fussy.

 

[FUSEServices]

I've prob gone a bit too far there!! But like I said, pulled one out today, an alarm cable that had been chewed by a rodent of some sort, so gone in with conduit now and pulled in a new cable. If the original installer had bothered to take 2 mins more on his install, then the home owner would not have been woken up in the middle of the night, ****ting themselves, along with half the street, and done without a house alarm for a week and a half! (and pay me half a days labour trying to find the dam fault). He probably had a ...........MAGNAMOLE......bless!

 

[Myles]

Just wait till the next time I see a NTL / BT bloke doing an install. Gonna pull him up.....'Oi where's your conduit you bodger'

 

[FUSEServices]

Not their fault though - they work for a company that tries to make as much money as possible by spending the minimum they can get away with!

I'm just a little conscientious - maybe too much sometimes, but it's not hard to do a job the right way instead of the quick, cheap and cheerful way.

 

[Des 56]

So what if the insulation deteriorates, and damp bridges L & N, no rcd protection and on a 32A fuse???

Your telling me that the fuse will trip before a fire starts - I don't think so mate!

Acrobatic rodents? ? ? Yep they sure are, have you not seen any??

NO problem with lack of support, that's not going to happen in a domestic situation?

I guess you run cables straight through then?

I dont want to get into a slanging match with you especially about something so trivial in the scheme of safety issues that its no big deal, cavity or not, conduit or not, acrobatic rodents I might concede

The likelyhood is that the cable will be twin +earth and if the insulation deteriorated the breakdown would most probably occur between a live/neutral and earth rather than live-neutral
This type of fault can occur anywhere at any time and the protective devices should operate in a system to prevent danger of fire,so yes I am not telling but suggesting that a fuse or rcd will go before a fire starts,not certain but very probable
I have rarely seen rodent damage that becomes more than an occasional nuisanse and dont consider them as too much of a problem or I would install cable that suited the expected environment
Cables in cavities in conduit or not in conduit are very unlikely to have any form of support,this as you know is a requirement of the regs that is being thrown aside domestic or not
I run cables straight through with no conduit and I probably breach a few building regs doing so,but I dont consider it has any or very few implications for electrical safety,perhaps bending a few regs to perform in the real world
As I said earlier,more of a structural problem than anything electrical safety related
Well thats my take on it,your wellcome to yours and will get no critisism from me

Mate