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No idea.



No you are not, but on quite a few occasions I've had to tell someone newly moved into their shiny new house that I cant change the cheap crappy plastic accessories for quality flat plate without chopping out the boxes and inevitable damage.
Just because the original installer doesn't give a **** what happens once he's done.[/QUOTE
 
For all the time that it takes to go 10mm deeper with an Armeg box-cutter into brick, I don't see there being any great problem installing 35mm metal boxes throughout on rewires. I once used 16mm boxes for switches and 25mm boxes for sockets, but came a cropper when a customer invited me back two years after I had rewired her house to replace all the original white accessories with flatplate equivalents. She was most disappointed that she couldn't have all those shiny new sockets and switches that she'd bought installed without walls being damaged to accomodate deeper boxes, and felt that I should have taken this into consideration when the rewiring was being done. Know what? .... she was quite correct. Customer lost, painful lesson learned.
 
Hi all,

Used to doing small 2 bed and 3 bed new builds so cable sizing is never an issue

got a huge 7 deb house 5 floors to do in the next 6 months, had a quick look and now wondering what cable size to use, before i get the book out i thought id post here for more advice

4.0mm legs for ring then 2,5 or 4,0mm all the way, seems to be quite a bit more expensive than 2,5mm also on the lighting 1.5mm to feed the first point then 1.0mm after.

or other option is radials, seem to be getting more common now and some favor over rings.

putting a large 24 way board in for the extra rings and lighting circuits

any advise would be appreciated , also told me he wants the cables capped ggrrrr, you guys use oval tube or channel for this these days?.

Cheers
Grand
Wants cables capped - oval tube or channel? I would consider costing FP200 GOLD or (not quite as good) No Burn Platinum screened fire-proof cables in white. These cables are fully protected against damage due to their ally foil screen, bend easily, outer strips more easily than standard twin&E (score lightly, bend twice and pull). Yes, they are a fair bit dearer but installation is a relative doddle and much quicker than capping or conduit. You can run them without worrying about wall position (though be sensible) and they are BASEC approved. The also work brilliantly with the Hager (and other) push-connect 'maintenance free' junction boxes (which can be in concealed locations) - that way you can avoid doing the switch connection inside the light fitting, reducing cable lengths and making installation quicker and easier. Can't use this on budget jobs, but very worthwhile on large or quality jobs. I would still use large size PVC twin&E to feed any sub-boards in a large domestic installation.
 
Where is this 24way db going? I would certainly be running a sub board to accomadate top 2/3 floors where electrical consumption will be minimum assuming theyre mainly bed/bathrooms. I agree with installing 35mm especially if its stud/D&D walls.
 
I was under the impression that for a cable to be installed outside safe zones the earthed screen must be compliant as a cpc in it's own right. This would not be the case with the foil screen on FP200.
 
Thanks for the links - they clarify things. I talked with the head of BASEC at an IET meeting on ring vs radial wiring some years ago and he wrote to me and confirmed that FP200 and similar BASEC approved screened cables could be used running almost anywhere - but always on a standard type B 30 mA RCD protected circuit. Now fire-alarm supplies should not be RCD protected (as the voltinium article states) - so they have to be run in "protected" areas to avoid the likelihood of later nail or screw damage.
 
Thanks for the links - they clarify things. I talked with the head of BASEC at an IET meeting on ring vs radial wiring some years ago and he wrote to me and confirmed that FP200 and similar BASEC approved screened cables could be used running almost anywhere - but always on a standard type B 30 mA RCD protected circuit. Now fire-alarm supplies should not be RCD protected (as the voltinium article states) - so they have to be run in "protected" areas to avoid the likelihood of later nail or screw damage.

I'm not sure you've got the wording right there.
 
Thanks for the links - they clarify things. I talked with the head of BASEC at an IET meeting on ring vs radial wiring some years ago and he wrote to me and confirmed that FP200 and similar BASEC approved screened cables could be used running almost anywhere - but always on a standard type B 30 mA RCD protected circuit. Now fire-alarm supplies should not be RCD protected (as the voltinium article states) - so they have to be run in "protected" areas to avoid the likelihood of later nail or screw damage.
I'm not sure you've got the wording right there.
Thanks for pointing out my mistake. The voltinum article:
Fire alarm cables for use in thin walls or partitions - http://www.voltimum.co.uk/articles/fire-alarm-cables-use-thin-walls-or-partitions-0
actually points out that no routing of screened cables should rely on RCD protection alone with regard to cable protection - whatever the supply purpose of the cables. The article then goes on to point out that both FP200 Gold and FP Plus have thick aluminium sheaths that do pass the nail/screw penetration tests - so they may be run more freely (though of course with common sense!). Some other screened cables have an aluminised plastic screen and they cannot legally be run so freely as they do not pass the penetration test requirements.
 

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