Installation of domestic sub-mains to individual flats

[Mr S Parks]

Hi. I'm new here and would value some help.

I hope my story's not to long winded

Installation of domestic sub-mains to individual flats(Scottish Power/SSE area).

Said flats are part of development renovating a 200 year old building with a few attached stables(in the form of a square) into private flats.

Was used as a commercial/small industrial facility until recent times and some remnants from such a history still present ie pipes and pyro.

This is the start of the project. This stage is converting the old stable square into flats. The individual flats to be supplied from communial/Benco locations containing cable head and metering. This is where 3(perhaps) flats will be supplied from and another similar location supplying the remaining 5? flats.

Cable route will be from said supply locations using suspended cable tray, via the attic spaces of the flats(so your neighbours cables may well be in your attic), attics are restrictive in space and then down through the fabric of the insides of flats to, normally awkward, cu locations. Most flats will have their external walls stripped of lathe an plaster, framed out and sheeted. All flats are different each with a ground and 1st floor.

I think SWA will be heavy and inflexible for such a route. Have had a look on the internet for ideas viz: SY(steel braided), split concentric and.......SWA.

Also, will there be a requirement for isolation/Rcd at either end of cable in addition to DNO isolator and mains incommer?

My experience is more new build, Approved, subcontractor status and signing of as Electricain responsibe.

Hope the above makes sense and any learned/experienced views much appreciated.

Regards

Mr S. Parks

 

[Evans Electric]

If I were you I'd forget SY   ,  its  useful cable  but has no standards  or BASICS approvals .   Also I'm fairly sure it doesn't go to the bigger sizes  you'll need. 

Also , I think we discussed on here ,  we can't use split con under 7671  ,  mainly , again I think,  because there is no outer earth  (SWA)   

Just use SWA  it'll be the cheaper option anyway. 

As for isolation ,  yes cables runs like you describe require  fusing and isolation but not RCD  .      Although you say the mains will pass down through the building  fabric in the flats ,  this means , if you bury them in the wall they'll require RCDs   or mechanical protection  . You don't really want to be burying a big SWA cable in the wall  , well I wouldn't  anyway .  

 

[Murdoch]

Personally I'd use SWA to avoid having issues with RCD's in series......... and yes you will need a switch fuse by the incomer - as a general rule over 3 m from the head to the CU dictates this

Where are the meters going to be?

 

[Mr S Parks]

Wow, thanks for the help.

Meters are located with cableheads. Distances between cablehead/meters to cu's vary between 15-55m with a variety of corners to negotiate. 

 

[Murdoch]

55 metres- wow

 

[binky]

defo SWA is the only real option, and I would consider some form of service duct (could be used for venting bathroom fans etc aswell?) for leccy from attic spaces to a utility cupboard to avoid burying cable in walls as per comments above.

 

[Mr S Parks]

Hi Blinky, ta for taking the time. Also Evans an Murdoch

By a service duct do you mean someting running through attics made by joiners? Wooden tray for lying cables, toilet vents on?

 

[binky]

:maria: