DIY Forum

DIY Forum/Home improvement advice

 

 

A-Z CONTENTS | DISCLAIMER | DIRECTORY | DIY VIDEO | HOME | SAFETY FIRST | FORUM RULES

It is currently Wed Apr 23, 2014 12:47 pm
Drainage online 


Time zone: Europe/London [ DST ]




 

 


Post new topic Reply to topic  [ 8 posts ] 
Author Message
PostPosted: Fri Oct 16, 2009 8:27 pm 
Offline
Newly registered Member

Joined: Fri Apr 28, 2006 8:30 pm
Posts: 38
Has thanked: 0 times
Been thanked: 0 times
Hi All,

Hopefully a straightforward question (or two ish)

Garage is currently supplied by 2.5mm T&E strung across the side passage originating from a 16a CB on the household CU. All bad, I know...

So, I've just run a 10m length of 3-core 6mm SWA ready to connect a 40m CB on the household CU and in to another CU in the garage.

The questions:
1) The household CU has and RCD protecting this fuse so I'm not proposing to use an RCD in the garage too. I believe that using two on the same circuit it both unnecessary and potentially troublesome as one can cause the other to trip. (I have experienced this when I used a plug-in RCD on a protected circuit). Have I got the right end of the stick here?

2) The household CU is a plastic MK unit. Do I need to terminate in a metal box first and then route to the CU or can I use the 3rd core of the SWA to earth rather than the steel protective layer of the SWA (i.e. go straight in to the CU? Similarly, at the garage end - should I try and get a metal CU or...?

3) Can someone explain "metalclad" CU's to me. The one's I've looked at look like they're made of plastic. Are they supposed to be metal boxes or am I just not understanding?

Cheers


Top
 Profile  
 

You may not be able to see the full post including pictures unless you register or log in

 Post subject:
PostPosted: Fri Oct 16, 2009 10:41 pm 
Offline
Site Admin
User avatar

Joined: Sat Jul 16, 2005 8:06 pm
Posts: 22679
Location: Darwen, Lancashire
Has thanked: 387 times
Been thanked: 619 times
1) If I was doing it I would just have rcd protection at the consumer unit.

2) Use the third core for the earth, but you can also use the steel wire as an additional earth. Just get a couple of glands and then connect the earthing tab to the other earths. terminating armoured cable

3) I always thought metalclad CU's were made from metal too :scratch:

_________________
DIY | Diy Videos


Top
 Profile  
 
 Post subject:
PostPosted: Sat Oct 17, 2009 12:14 am 
Offline
Deceased 21-10-2011 R.I.P
User avatar

Joined: Fri Jan 20, 2006 6:03 pm
Posts: 5956
Location: East of England
Has thanked: 9 times
Been thanked: 94 times
Use a metal box at the house end. I've always thought plastic's too flimsy to hold a SWA gland. Then a bit of twin & E to the consumer unit. Use a banjo washer with the gland for an earth terminal.

I've never seen a plastic metalclad CU either...

_________________
I should be dead; I've cheated the Grim Reaper yet again by surviving my third heart attack in June.


Top
 Profile  
 
 Post subject:
PostPosted: Sat Oct 17, 2009 8:30 am 
Offline
Newly registered Member

Joined: Fri Apr 28, 2006 8:30 pm
Posts: 38
Has thanked: 0 times
Been thanked: 0 times
Thanks for the replies. I suspect it's just me thinking the CU's i've see are plastic when they are, in fact, metal.

With regard to the metal box at the house end... Can someone post a link to the type of thing I need. I've trawled through TLC's site but could only find quite expensive and large metal switchboxes and switchfuses - all of which seemed overkill just to terminate the SWA.

And to confirm... a metal CU in the garage would be fine for wiring the SWA straight in to?

Thanks again.


Top
 Profile  
 
 Post subject:
PostPosted: Sat Oct 17, 2009 9:34 am 
Offline
Site Admin
User avatar

Joined: Sat Jul 16, 2005 8:06 pm
Posts: 22679
Location: Darwen, Lancashire
Has thanked: 387 times
Been thanked: 619 times
Something like this for terminating the SWA into- http://www.tlc-direct.co.uk/Main_Index/ ... index.html

Metal CU in garage will be fine, but I'd use a gland at each end of the SWA for the termination, you can also use the outer sheath as an additional earth as well then :wink:

_________________
DIY | Diy Videos


Top
 Profile  
 
 Post subject:
PostPosted: Sat Oct 17, 2009 10:31 am 
Offline
Newly registered Member

Joined: Fri Apr 28, 2006 8:30 pm
Posts: 38
Has thanked: 0 times
Been thanked: 0 times
Ah, that's much better. Thank you.


Top
 Profile  
 
 Post subject:
PostPosted: Sat Oct 17, 2009 5:57 pm 
Offline
Senior Member
User avatar

Joined: Sat Aug 13, 2005 8:11 pm
Posts: 2258
Location: Staffordshire
Has thanked: 3 times
Been thanked: 149 times
Just remember where you gland it off into the box at the house end you need to run an earth from the brass earth tag to your consumer unit aswell as the core in the swa, you have to bond the armour to earth .

Nick

_________________
If it isnt broke dont bloody touch it until it bloody well is and if it is broke then make drawing of the connections before you remove the broken one and replace with a new one LoL


Top
 Profile  
 
 Post subject:
PostPosted: Sat Oct 17, 2009 9:53 pm 
Offline
Newly registered Member

Joined: Fri Apr 28, 2006 8:30 pm
Posts: 38
Has thanked: 0 times
Been thanked: 0 times
I understand - makes sense. Many thanks.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 8 posts ] 



Similar topics
   

Time zone: Europe/London [ DST ]


Who is online

Users browsing this forum: No registered users and 3 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  


News News Site map Site map SitemapIndex SitemapIndex RSS Feed RSS Feed Channel list Channel list
ultimatehandyman privacy policy

Contact

 



phpBB SEO