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Bootlace ferrules and 16mm^2 crimps

Discussion in 'Electrics UK' started by markocosic, 8 Feb 2013.

  1. markocosic

    markocosic

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    Hi,


    When dealing with stranded cable (my cooker supply and original ring main are in stranded, do the regs care how it is terminated? Is it acceptable to use bootlace ferrules to make life easier when terminating? These:

    http://www.tlc-direct.co.uk/Products/DVDK2G.html


    When attaching cable to bonding clamps, do the regs care how it is terminated? Existing bonding has the bare conductor trapped under the washer on the clamp. Is it acceptable to use crimped rings to make life easier when terminating?

    http://www.tlc-direct.co.uk/Products/DVDKB1516.html


    Cheers,

    --
    Marko
     
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  3. SaladFingers

    SaladFingers

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    I always use bootlaces and the regs don't care if you do or not.

    And with screw terminals for earth clamps and such a like I always use ring terminals, it looks better than without and ensures a proper and secure termination.
     
  4. bernardgreen

    bernardgreen

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    I can't answer about the regs but crimped ferrules do make for a better termination but only if the crimping is done properly with the correct crimping tool. I have seen a few ferrules so loosely crimped that even though the terminal was screwed dowb tight the strands could be pulled out of the ferrule,
     
  5. SimonH2

    SimonH2

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    Biggest problem I find with ferrules is that many accessories don't have enough room for the plastic lead-in bit - particularly if the cables are large or there is more than one in a terminal. Eg, when fitting a jumper between earth terminal a socket and backbox using 'single' - it can be impossible to get the cable into the earth terminal along with with the 2 CPCs in the supply cables when it has a ferrule on.

    Does depend on the design of the accessory, and how deep they recess the terminals in the moulding.
     
  6. Spark123

    Spark123

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    Please can you elaborate on what you are implying by "Stranded"? Post a pic up?
    I have a feeling you are talking about bog standard twin and earth cable with the 7 or so strands?
     
  7. SaladFingers

    SaladFingers

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    You can get ferrules without the plastic shroud.
     
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  9. markocosic

    markocosic

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    Thanks all; I'll use 'em.

    Yes, it's imperial (PVC/PVC, tinned conductor) T&E Spark123. 7/.029 for the socket ring and 7/.044 for the cooker radial. Gorgeous stuff. Crimps well into the 2.5 and 1.0 mm^2 ferrules if you're patient enough to feed it in in the first place.

    Also some 1.0 mm^2 2-core flex in pendant ceiling fittings, and 3-core where the ceiling rose is in the attic space and there's a surface mount fitting on the other side. (bathroom)

    On a similar theme...

    Terminating single stranded T&E. Do you fold the end back on itself or not? I've been using both. Where it is a pair of 2.5mm^2 into an MCB or socket back intended for it, I leave them as "single" ends as the clamp bare "bridges across" them and holds them down nicely. Where I've just got a screw terminal (earth and neutral bars, for example) I've folded the end back on itself and then inserted it into the terminal, as it's more secure. Single cooker radial into MCB no. Single lighting radial into MCB yes. Are there rules on it, or is "secure" all it says?

    Twisting earths. Do you twist earths together before terminating? I haven't been, as the terminals on the sockets etc seem to clamp better/are less prone to "relaxing" if you don't twist together. I'm making this up as I go along though - any guidance from the pros?
     
  10. Scoby_Beasley

    Scoby_Beasley

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    Two conductors put them in. One conductor, double it over (fold it back).
    Never. And you also sleeve them singly.
     
  11. 333rocky333

    333rocky333

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    Really even for sockets

    Actually since the 17th regs was introduced they do regarding certain stranded cables,
     
  12. SaladFingers

    SaladFingers

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    Not for sockets, never found a 16mm2 cable to fit a socket
    :rolleyes:
     
  13. markocosic

    markocosic

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    To confirm; no restrictions on bootlace ferrules on 2.5mm^2 and 6mm^2 (or imperial equivalents)


    With regards the comments on cables that got vapourised in the moderation, a brief history of the property is as follows:

    Built 1950s (I think), back when the council didn't treat tenants with contempt and the tenants didn't treat the properties that they were given with contempt. (80 mm cavities, brick both leaves etc)

    "Cooker" "sockets" and "lights" with a metal fusebox. Earths on the cooker and sockets. No earth on the lights. This was rewired in 1983, with an additional socket ring, an electric shower, all the lighting circuits replaced with T&E, and a split-load board with 30mA RCD for the sockets/shower. Again pretty good for the era, the workmanshpi wasn't at all bad, and had there been nothing else done to it I might well have left it alone. However...

    Part P Pete the kitchen fitter came along, so now the end of the cooker radial is all dog-eared and jointed behind tiles.

    Handy Andy the bodger came along, fitting downlighters in the living room, two-way lighting to the hall light, and an attic conversion. The lights downstairs flickered and made "bzzzzt" sounds if you jumped on the floor upstairs. (loose rose left under the floorboards as a JB) The two way switching was wired in such a way as you could turn the hall light on from downstairs, upstairs, or indeed both, but off required all switches to be off. The two lighting circuits were also linked in the process of fitting the two-way and the downlighters. Attic sockets fed off the upstairs lighting ring, obviously MCBed at dual 6A rather than single 6A due to the fudged wiring. Fugly metal light fittings with the earths not connected; ceiling pendants with the outer cores showing rather than the sheath

    An SSIB certified mouth-breather fitted an alarm badly, and was probably the one to lose the blanks for the consumer unit/strips it's faceplate threads.

    Then some Polish folks bought the house, and added double sockets by screwing/sticky-pad attaching them over the singles, with chocoboxes for live and neutral, but earth was too much trouble. Spurs off the ring by poking 1.5mm^2 T&E between the faceplate and the wall, then hanging 3 sockets off it.

    Most faceplates or lightswitches were cracked in some shape or form, and many of the original ones had loose wires. (no ring continuity on N or E)

    Bonding wasn't up to scratch (gas not bonded at all, water bonded >>>600mm from the entry point and in 6mm^2)

    CU had missing blanking plates such that if you went for the main switch you'd probably get the live busbar instead, the shower was running off too small an MCB, and not all circuits had RCD protection.


    All sounds nasty, but was fairly straightforward (untangling the lighting circuit excepted!) to bring "up to code" by changing all the faceplates and either extending the ring properly or removing the extensions, and swapping the CU for a 17th ed affair.

    Cables were perfectly sound though; enough slack left in 1983 to do what needed to be done without replacing them, save for the cooker cable which gets a ruddy great JB and a new end on it, and some lighting cables that were easier to tear out and replace wholesale than terminate where they've been cut.

    Perhaps this will bite me, and 30/50 year old PVC T&E will fail a hi-pot/megger test. I doubt it though to be honest; as I've never seen anything that "looks ok" not be ok. (though I have seen plenty that is obviously naff or nicked/gashed by another trade pass the megger even thought it failed a visual)
     
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