Tin ?

Discussion in 'Electricians' Talk' started by ADSL Nation, Feb 10, 2004.

  1. ADSL Nation

    ADSL Nation New Member

    You wouldn't believe the electrical installation in my house. It has 3 big cast iron DP switches connected to the meeter via a junction box. Each DP switch has fuse wire on both the Live & Nutral lines !. Anyway needless to say it is in need of a serious update. I am puting as much in place as possible myself before getting an electricitian in to to complete the parts that I have isufficient knowledge of.

    The Garage is currently running of a 2.5 T&E spur so needs replacing with it's own small consumer unit running of an MCB on a new master CU. One of the cheapie screfix ones will probably do. So I plan to replace the cable with 6mm 3core SWA. As SWA is stranded I was wondering the wisdom of tinning the end of the strands. It might sound like a trivial thing but I am keen to minimize noisy electrical supply. My thought is that tinning the end (putting a small amount of solder to stick the strands together) will ensure a solid connection with maximum conductivity. Is there any reason why I should not do this ?

    In case you are wondering why 6mm SWA, I am keen to over spec where possible to allow for any future upgrades.
     
  2. ban-all-sheds

    ban-all-sheds New Member

    Why SWA at all, and not 6mm T/E? Are you sure that the walls of that cheapie CU will take the strain of a SWA gland? And is there enough space inside it? And why 3-core, not 2?


    As for noisy electricity - I've never heard mine make a peep :^O
     
  3. ADSL Nation

    ADSL Nation New Member

    SWA, because it will be burried as the garage is not attached to the house, it is about 2m away. 3 Core is belt & Braces approach where using both a core and sheething as earth gaurantees a good earth and gives the option to use the 3rd core for something else should the need arrise in the future.

    My line of thinking is that with the tip of the stranded SWA tinned all of the individual strands are stuck together making sure they are all making connection and that it is easier to get all strands in to the connector, just like it is esiear to wire a plug if the stranded wire is tinned at the end.
     
  4. RES

    RES New Member

    I would be cautious of tinning the end of your cable if you are going to terminate them into a screw fitting. The solder will make the conductor strands solid and difficult to compress. Over time the solder can breakdown and leave you with a loose connection. Best to only solder if you are going to 'stick' things together. Leave the ends natural and let the screw terminal do it's job properly.
     
  5. Damocles

    Damocles New Member

    yep, we used to have some of those big switches...only ours were replace3d 30 years ago. I think Both wires have a fuse because either one could be live! maybe this reflects on your supply earth issue. Perhaps Earths werent part of the original installation scheme. Hadnt been invented.
     
  6. ban-all-sheds

    ban-all-sheds New Member

    I think ADSL has bigger things to worry about right now than the niceties of SWA termination......
     
  7. RES

    RES New Member

    One solution to terminating your SWA cable is to fit a galvanized steel conduit terminal box to the outside of your house and workshop/garage. Fit SWA glands to the threaded conduit entry, this will make-off the armour wires, then connect the cores via terminal blocks to 6mm T&E, which you can run in through the back of the box straight into your house and garage/workshop CUs. This should be far easier to work with.
     
  8. The Trician

    The Trician New Member

    RE: Both wires 'fused'. You might find that the neutral has a solid link inside the fuse carrier, and that it is not 'Fused' at all, at least not in the conventional sense. Used to be like this years ago.
     
  9. ban-all-sheds

    ban-all-sheds New Member

    One solution to terminating your SWA cable is to fit a galvanized steel conduit terminal box to the outside of your house and workshop/garage...

    Wouldn't it be better inside, with the SWA coming through the wall? I'd worry about water ingress to the box via running down the wall behind it and in through the holes.

    Or am I paranoid?
     
  10. ADSL Nation

    ADSL Nation New Member

    I pulled the cartridge and both have fuse wire in them.

    Re: SWA if there isn't enough room in the box for a gland then I will bring the cable throgh the wall and terminate it in some sort of junction. There must be one for this purpose I assume and then ran T&E to the consumer unit.
     
  11. RES

    RES New Member

    Ban-all-sheds

    The boxes I am talking about are designed for outside use, the only vulnerable entry is where the box is screwed to the outside wall, and a hole drilled through the jb and into the wall for the cable to bass through. If it's nice and flush, and the conduit/gland entry is at the bottom it works like a dream. I only know because that's what was fitted to my house/garage. I've never had any problems, and it's the best way of making off SWA I've seen. Like was said before bringing SWA into a plstic CU would be hell.
     
  12. Tired-old-git

    Tired-old-git New Member

    boys what are you all thinking just use a earth clamp on armoured sheeth inside garage and terminate to a armoured gland the usuall way whats this with the soldering? are u a engineer /electronics type ?
    glands are designed for the job and for a extra measure clamp on a earth clamp run a piece of say 6mmm earth wire to the earth terminal inside box its got mechanical and electrical strengths ....
    ....voila a piece of **** ...lol:)
     
  13. ban-all-sheds

    ban-all-sheds New Member

    The boxes I am talking about are designed for outside use, the only vulnerable entry is where the box is screwed to the outside wall,

    I didn't even consider that - I just assumed that the fixing would not compromise the IP rating, i.e. it would be an external flange, or inside the box but outside the part protected by the gasket, like the little Masterseal ones.


    and a hole drilled through the jb and into the wall for the cable to bass through.

    That was the area that concerned me, as you couldn't use a gland at the back of the box. I guess you could put a generous bead of silicone sealant on it though.


    If it's nice and flush, and the conduit/gland entry is at the bottom it works like a dream. I only know because that's what was fitted to my house/garage. I've never had any problems, and it's the best way of making off SWA I've seen.

    Flush? You've not seen my walls, then... Wonky and pebbledashed - I'd have to have the SWA and the T/E entering the box at the bottom.


    Like was said before bringing SWA into a plstic CU would be hell.

    I woudn't want to try it...
     
  14. ADSL Nation

    ADSL Nation New Member

    My house is wonky pebbledash as well. I will be comming stright through the wall in to the floor void. The floor void is quite deep (1m) and I have installed an access hatch in the kitchen that lets me crawl arround under the whole house. Great for installation of cables & pipes.

    So I thought I would bring the SWA in at about 80mm down from the floor joists and then bring it up the wall about 50mm. Install a box to terminate it in there and run 6mm T&E from there to the CU. I just need to find a suitable junction to terminate it with. I am not certain if this http://www.screwfix.com/app/sfd/cat/pro.jsp?id=15995 is the right thing as it doesn't give any ratings.

    Shurley there should be some simple metal clad box with 6mm (62A) capable terminals that the gland would fit in to and a grommet for the T&E.

    The reason for the soldering is, yes I am an electronics enginner type. My specialist area is networking & telecomunications where a joint needs to be more than simply electrically sound. In these situations you have to make sure that you don't introduce excessive capacitance or reflections etc. Something as simple as tinning the end of the wire can reduce rf harmonics.

    Being the nerdy type I am, I always look in to the smallest details of everything. I like to have the cleanest possible mains supply. The idea being eliminating as many sources of noise as possible before they even reach the equipment. The equipment obviously has its own noise reduction on the supply, but I feel prevention is better than cure. The equipment that I use for recording will be on its own MCB for example to take advantage of the attenuation in the wiring to reduce the effect of noise generated by things like fridge compressor. In fact I also have surge arresting plugs fitted on the fridge & frezer to reduce the spikes they cause.
     
  15. ADSL Nation

    ADSL Nation New Member

    I must be a tradesmans best and worst customer.

    As I like to have the job done the proper way even when it is not absoloulty necessary. So for example there was a large blown spot in the plaster on the wall that could of been just patched, in fact that is exactly what my nighbour did with his. But as the plaster was the original from the 1930's I completlely removed all plaster in the room and had it redone from scratch. At least I know that the plaster will probably out-live me so I will have no reason to return to it later. Eventually the entire house will have new plaster.

    On the other hand I often end up asking the tradesmen to do things they rather wouldn't. At the end of the day they don't care as the more work the more they can charge. But it must be a real pain when your customer starts specifying detailed requirements. Like when I asked the plumber for very specific routing of pipes rather then just say "can you bung a radaitor over there".
     
  16. ban-all-sheds

    ban-all-sheds New Member

    My house is wonky pebbledash as well. I will be comming stright through the wall in to the floor void. The floor void is quite deep (1m) and I have installed an access hatch in the kitchen that lets me crawl arround under the whole house. Great for installation of cables & pipes.

    Well definitely get a Sparky in then, one with an apprentice - they're specifically designed for crawling round in floor voids, and you can have some fun closing the access hatch and putting heavy furniture on it


    So I thought I would bring the SWA in at about 80mm down from the floor joists and then bring it up the wall about 50mm. Install a box to terminate it in there and run 6mm T&E from there to the CU. I just need to find a suitable junction to terminate it with. I am not certain if this http://www.screwfix.com/app/sfd/cat/pro.jsp?id=15995 is the right thing as it doesn't give any ratings.

    Yes it does - it says it's IP68, which is a bit OTT for indoors, and note you are paying for that level of protection - it aint cheap. Also, it doesn't look as though it would easily take a SWA gland.

    Some of these might be more appropriate:

    http://www.tlc-direct.co.uk/Main_Index/Boxes_and_Enclosures_Index/BoxesAdaptable/index.html

    http://www.tlc-direct.co.uk/Main_Index/Boxes_and_Enclosures_Index/Boxes_AdaptableMoulded/index.html

    Have you thought about whether the cables in that void should be protected against rodents?
     
  17. ADSL Nation

    ADSL Nation New Member

    he he, just relized that writing messages in the wee small hours when half asleep is a bad idea. mm should ofc read cm.

    looks like this might be a suitable box complete with terminals.

    http://www.tlc-direct.co.uk/Products/LBB9TM.html

    What I meant about ratings is that there is no electrical rating for the terminals. AFIK the IP rating is just the Ingress protection. Where the first number is solids and the second liquids. As the box will be indoors there is no real concern about IP rating.
     
  18. ADSL Nation

    ADSL Nation New Member

    Going to drop in to my local Newey & Eyre where 6mm 3 core SWA is just 85p +VAT per metere. They will almost certainly have a suitable box as well.
     
  19. ban-all-sheds

    ban-all-sheds New Member

    Ah - sorry - didn't realise you meant electrical ratings. That Screwfix box doesn't list any because, presumably, it doesn't have any - it's just a waterproof box wherein you join cables using the method of your choice...
     
  20. The Trician

    The Trician New Member

    Yes! Same as me. I had a drawing ready for the plumber when he came to install my new boiler etc. I'd even got the floorboards up and had run some JG Speedfit for the washing m/c water supply. Just to ensure that it went exactly where I wanted it to go! All he had to do was to join onto the existing adjacent copper.
     

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