IET logo
 
IET
Decrease font size
Increase font size
Topic Title: New meter position
Topic Summary: SWA through house.
Created On: 31 October 2013 08:50 AM
Status: Post and Reply
Linear : Threading : Single : Branch
Search Topic Search Topic
Topic Tools Topic Tools
View similar topics View similar topics
View topic in raw text format. Print this topic.
 31 October 2013 08:50 AM
User is offline View Users Profile Print this message



SherlockOhms

Posts: 320
Joined: 05 April 2011

Tricky one this.

House refurb requires the meter to move from what is about to become a shower room to whever the DNO deem fit on the day. My guess is outside, similar to the adjacent properties.

Customer is defiant and refuses to have his CU in the living room prefering instead, the kitchen.....at the oposite end of the house.

It's a large property so a 100A supply will be required.

Given that a front end 30mA RCD isn't ideal (no disco between that and the RCD's in the CU) the quandry is how on earth am I going to route a 25mm SWA through the first floor joists (solid ground floor) ?

Any advice?

S.
 31 October 2013 09:15 AM
User is offline View Users Profile Print this message



aligarjon

Posts: 2799
Joined: 09 September 2005

Pressuming that you are going through the wall at the meter box rather than high level. Maybe Leave the armour on where it goes up the internal wall (obviously earth from the meter end). Then strip the armour off where it passes through the floor). this might give you a fighting chance and also presumes it won't be buried at less than 50mm anywhere. so will have to be surface kitchen end.
Or up and around the outside at high level, but will be difficult getting round the corners so probably a non starter.

I suppose you could notch the joists as it is armour ? a metal plate over the top might be a good idea. (probably the easiest)

Gary

-------------------------
Specialised Subject. The Bleedin Obvious. John Cleese
 31 October 2013 09:21 AM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 11251
Joined: 13 August 2003

Can it be trenched around the outside?
- Andy.
 31 October 2013 09:25 AM
User is offline View Users Profile Print this message



SherlockOhms

Posts: 320
Joined: 05 April 2011

Up/around the outside is out of the q as it's a terraced property.

I think relying on installing it at more than 50mm depth throughout it's length is risky.

25mmsq means whopping great holes in joists that already resemble Swiss cheese. Bend rads are going to be a nightmare!

I think the only option is front end RCD and something a little more pliable than SWA?

S.
 31 October 2013 10:49 AM
User is offline View Users Profile Print this message



aligarjon

Posts: 2799
Joined: 09 September 2005

What about a second external meterbox ?

Gary

-------------------------
Specialised Subject. The Bleedin Obvious. John Cleese
 31 October 2013 12:31 PM
User is offline View Users Profile Print this message



AJJewsbury

Posts: 11251
Joined: 13 August 2003

If it's a complete refurb, how about getting the underside of the joists battened out to create a service void between the underside of the joists and plasterboard ceiling and running the SWA through that?
- Andy.
 31 October 2013 02:53 PM
User is offline View Users Profile Print this message



Grumpy

Posts: 404
Joined: 09 January 2009

Could you go up the front wall into and across the loft and down the back wall?
 31 October 2013 05:29 PM
User is offline View Users Profile Print this message


Avatar for UKPN.
UKPN

Posts: 462
Joined: 17 January 2012

"its a large property"
in that case why not build a small cupboard in the hallway and have the service and d/b fitted in it.

Regards
 31 October 2013 06:15 PM
User is offline View Users Profile Print this message


Avatar for OldSparky.
OldSparky

Posts: 592
Joined: 28 June 2011

surely 16mm would be adequate

why would you need an RCD?
 31 October 2013 11:16 PM
User is offline View Users Profile Print this message



HarryJMacdonald

Posts: 254
Joined: 15 May 2002

SWA isn't the only armoured cable. Oil rigs are typically cabled in EPR (Rubber) galv wire braid cable which is much more flexible than SWA, probably a bit pricier too!
 01 November 2013 08:39 AM
User is offline View Users Profile Print this message



SherlockOhms

Posts: 320
Joined: 05 April 2011

I worked out a possible route and length for a 25mm SWA. Priced it, added on the labour (including an extra body to help) and presented it to the client.

The board will now go in the hall by the front door.

I love it when a plan comes together.

S.
 01 November 2013 09:45 AM
User is offline View Users Profile Print this message



MrP

Posts: 830
Joined: 24 March 2006

Sherlock
Good move to price the work out from taking place

But why would you consider SWA in a domestic when mechanical protection to the degree of SWA is not required
For me it would be split con every time as an engineering solution

MrP
 02 November 2013 12:48 AM
User is offline View Users Profile Print this message



alancapon

Posts: 5745
Joined: 27 December 2005

Split concentric does not comply with the 17th edition and would have to be protected by an rcd. Due to its construction, a third of its diameter is protected by the neutral, which BS7671 now regards as a live conductor. It does however still comply for the DNO on their side of the meter.

Regards,

Alan.
 02 November 2013 03:15 AM
User is offline View Users Profile Print this message



MrP

Posts: 830
Joined: 24 March 2006

Split con does not comply?
Alan you sure buddy put miles of the stuff in as sub mains on the consumers side apartment blocks
As long as you comply with the 50mm from the surface/RCD/E Mec protected or surface fix via trunking it works for me
Split con unless you can tell me otherwise
We over engineer things in the UK why install armour when you don't need to.

MrP
 02 November 2013 12:05 PM
User is offline View Users Profile Print this message



alancapon

Posts: 5745
Joined: 27 December 2005

Yes, that would be ok in my opinion. The problem would be where you were using the armouring to protect the cable, due to insufficient burial depth. In this case, to comply, you would need to use a cable with an earthed screen / armouring round the entire diameter of the cable.

Regards,

Alan.
Statistics

See Also:



FuseTalk Standard Edition v3.2 - © 1999-2014 FuseTalk Inc. All rights reserved.