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Discuss BS7671:2018 Proposed Changes in the Electrical Wiring, Theories and Regulations area at ElectrciansForums.co.uk.

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  1. hightower
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    hightower Electrician's Arms

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    Durham
  2. Andy78
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    Andy78 Trusted Advisor

    Location:
    Kingston upon Hull
    Yes, had a skim through them.
    Nothing that will cause too much pain in the wallet for contractor or customer, or too much hassle on the install side.
    I would like to know the justification for some of the mysterious new ideas though.
     
  3. hightower
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    hightower Electrician's Arms

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    Durham
    Well I suppose one of the biggest changes is the earth rod requirement for TN systems. I'm guessing it will be applied in a similar style to bonding requirements - no work to take place unless those are up to scratch - which is going to mean a fair old stock of electrodes in the back of the van.
     
  4. Andy78
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    Andy78 Trusted Advisor

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    Kingston upon Hull
    Not sure about that one. The regs ask that the earthing and bonding be "adequate" before alterations take place. I'm not sure you can say that all earthing systems are now inadequate unless a supplementary rod is added.
     
  5. mattg4321
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    mattg4321 Electrician's Arms

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    South East
    What's the real world benefit of a rod on a TN-S system?
     
  6. hightower
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    hightower Electrician's Arms

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    Durham
    But they wouldn't be deemed 'adequate' in the eyes of BS7671:2018. I get what you're saying, how can something we've been doing/using for decades suddenly become dangerous overnight, but my argument is why include that regulation if they aren't going to enforce it somehow.
     
  7. mattg4321
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    mattg4321 Electrician's Arms

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    South East
    Further to my post on the other thread can anyone find anything about AFDD's and where they will be required, other than they may be fitted!
     
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  8. Andy78
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    Andy78 Trusted Advisor

    Location:
    Kingston upon Hull
    It will probably be applied on new build.

    the introduction of the regs states that older versions of installs need not upgrading just for the sake of it nor need be considered unsafe.

    Who knows though ? We may be pushing rods in before we add a socket.
     
  9. Ian1981
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    Ian1981 Electrician's Arms

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    North east
    A rod would only make sense to me if it was tncs and it offered supplementary protection against an open pen conductor on the supply authority's cable
     
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  10. Ian1981
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    Ian1981 Electrician's Arms

    Location:
    North east
    Hopefully the schemes and potential manufacturers will give information on these devices before bs7671 18th edition comes into force because personally I haven't a clue what they are in the sense of size, wiring specification and when they are to be installed as I'm sure we are all possibly in the same boat so technical advise is most welcome
     
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  11. Ian1981
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    Ian1981 Electrician's Arms

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    North east
    Think we need not get too worked up over purposed regulations as this is only a draft copy and still around a year away so it's not worth losing sleep over it IMO

    Obviously can't take my own advice as my previous reply post demonstrated o_O
     
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  12. davesparks
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    davesparks Trusted Advisor

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    guildford
    Yes it the draft for public comment, that's why it's important that we read and understand it so that we can make informed comments on it.
     
  13. davesparks
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    davesparks Trusted Advisor

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    guildford
    It hasn't suddenly become dangerous overnight, the danger has been there, and been slowly increasing for many years.
    The problem is broken PEN conductors, there was an article posted on here about it not so long ago.
    A lot of our distribution system is somewhat antique with lots of new alterations and repairs with conversions to TNCS.

    The requirement to install earth electrodes connected to the MET has been common in other countries for many years and its introduction here is a good thing in my opinion, but only if they get the regulations right with regards to Ra values.
     
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  14. davesparks
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    davesparks Trusted Advisor

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    guildford
    I don't think we'll get anything more than the 'may be fitted' in this edition, they will slowly become a requirement over the next few amendments.
    I think the use of RCDs has followed a similar method of being brought in as a requirement
     
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  15. hightower
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    hightower Electrician's Arms

    Location:
    Durham
    But that all earthing and bonding must be up to standard. I'd read that as sticking an earth rod in aswell under these new rules.

    I understand the dangers with PEN conductors and how having an earth rod would reduce the risk, but why not just apply this ruling to TNCS? The draft says "supplementing any earthing facility provided by the distributor" - so why are they pushing it on TNS as well? Is it just to make sure they tick the boxes, so that any TNS that are later converted to TNCS for whatever reason will be covered?
     
  16. Ian1981
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    Ian1981 Electrician's Arms

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    North east
    Yeah I posted it after receiving an email from the electrical safety council.
     
  17. Ian1981
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    Ian1981 Electrician's Arms

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    North east
    I love how the supply authorities issue becomes the installers problem!
     
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  18. davesparks
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    davesparks Trusted Advisor

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    guildford
    I assume it is due to the widespread conversion of TNS services to TNCS.
    I'm not sure that there will be many TNS services out there which are fully TNS these days.
    Plus TNS isn't perfect and can suffer from a loss of its earth connection.
     
  19. static zap
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    static zap Regular EF Member

    Location:
    west midlands
    If clever enough should be good , but if noise is external to
    premises , could be back to "Nuisance value !"
    (with less AM radios about , some are less aware of
    consequences of gentle buzzing noises ! )
     
  20. Risteard
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    Risteard Electrician's Arms

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    Derry, Ireland
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    Walsh Electrical Services
    Most of the rest of the world has required Earth electrodes on TN-C-S systems from year dot. It's about time it was required by BS7671.
     
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  21. Ian1981
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    Ian1981 Electrician's Arms

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    North east
    Does actually any other European country use tncs?
    Always thought it was a uk thing
     
  22. Rpa07
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    Rpa07 2000 posts - only 46379 behind Telectrix! Electrician's Arms

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    Bristol
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    Ebenezer electrical
    Are there any statistics regarding the failing of PEN conductors and their occurances?
    There surely are monitoring systems available to DNOs for these occurances leading to rapid responses.
    I thought that TNCS was the future but if wrought with SO MUCH DANGER and the possible need for earth rod back up at every install, it strikes me as not that advanced!
     
  23. Andy78
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    Andy78 Trusted Advisor

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    Kingston upon Hull
    My initial thought is that if this is felt necessary as a requirement for safety due to the nature of the incoming supply, should this not be introduced into ESCQR and not have the onus for this safety measure put upon the end user ?
     
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  24. davesparks
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    davesparks Trusted Advisor

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    guildford
    Tncs is the future because it's cheaper to install, that's the main driving force behind its use.
    Nobody is saying that there is SO MUCH DANGER, just that there is a danger and it should be mitigated.
     
  25. davesparks
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    davesparks Trusted Advisor

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    guildford
    Increased csa of main bonding is a requirement for safety due to the nature of the incoming supply (PME) as is the use of rcds for fault protection (TT), nobody expects the DNOs to foot the bill for it so why should this be any different?
     
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  26. Andy78
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    Andy78 Trusted Advisor

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    Kingston upon Hull
    Yeah good point.

    I hope guidance is brought out as to what is expected of an installed electrode for these purposes though. Round these parts a 3/8" rod bashed halfway into the mud and rubble under the floor under the stairs seems to constitute a permanent TT arrangement when the sparky can't be bothered to call the DNO and wait a couple of weeks for a connection.
     
  27. Ian1981
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    Ian1981 Electrician's Arms

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    North east
    Then why not do away with that possible problem and go back to TN-S?
    Cost is the reason pure and simple.
    no risk of raising the earth to mains potential due to open pen conductor and no diverted neutral currents.
    Earth can still fail of course.
     
  28. telectrix
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    telectrix Scouser and Proud of It Trusted Advisor

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    cheshire/staffordshire
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    Telectrix
    sod it. i'm going back to the 16th. RCDs only where sensibly required, CUs didn't spontaneously combust, no 5wws, shared neutrals save cable, no cat 5 run everywhere, sound in every room created by leaving doors open and turning the volume up. and only 4 channels of garbage on the telly instead of 200 . good old days.
     
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  29. Pete999
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    Pete999 Trusted Advisor

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    Northampton
    BBC1 BBC2 ITV and C4 if you were lucky Apprenticeships, Plastic CUs and on and on and on. Glad I'm out to grass, or out to Red Vino, never did like grass, gives me Hay Fever, as well as a hangover. Tried that Mid Eartern stuff once Gaaat I think it was bit like a Privet hedge.
     
    Last edited: Jun 7, 2017
  30. Pat H
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    Pat H Don't ask, get an Electrician in.

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    Ware Herts
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    Sparks of Intelligence
  31. davesparks
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    davesparks Trusted Advisor

    Location:
    guildford
    I would imagine the fact that it is almost impossible to do that would have something to do with it.
    Also a TNS system these days would not be as good as it was due to the type of cable used these days. The old TNS systems relied in part on the lead sheath being in contact with the earth and forming one large earth electrode, modern plastic insulated cables won't offer this advantage.
    And as you say, the earth can still fail.
     
  32. anthonybragg
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    anthonybragg Electrician's Arms

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    NORTHAMPTON
    Business Name:
    CHARLTEC ELECTRICAL LTD
    But remember that the supplier does not have to provide a earth facility.
     
  33. Pete999
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    Pete999 Trusted Advisor

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    Yes the reason for this edict is the failing of older U/G cables or degrading with age
     
  34. Flanders
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    Flanders Regular EF Member

    Location:
    Tamworth
    Will be interesting seeing how many domestic installions get condemned for no earth rods, I noticed that now all lighting circuits in domestic installations will have to be rcd protected which is just belt and braces to make sure rcds are fitted on all circuits in a house .
     
  35. Ian1981
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    Ian1981 Electrician's Arms

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    North east
    Ca
    but 99% of the time they will unless there's a good reason not to
     
  36. anthonybragg
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    anthonybragg Electrician's Arms

    Location:
    NORTHAMPTON
    Business Name:
    CHARLTEC ELECTRICAL LTD
    What happens if you live in a block of flats ? or if your posh apartments
     
  37. Andy78
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    Andy78 Trusted Advisor

    Location:
    Kingston upon Hull
    I can still think of plenty of types of circuits that have no requirement for RCD protection, installation method dependant of course.
     
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  38. Andy78
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    Andy78 Trusted Advisor

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    Kingston upon Hull
    Flat below will have to find a use for the copper coated ceiling decoration they now have.
     
  39. davesparks
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    davesparks Trusted Advisor

    Location:
    guildford
    Well the sensible people will install earth electrodes connected to the MET of the incoming supply to the building.

    The less sensible people will be clipping green and yellow cables down the outside of the building to earth rods.
     
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  40. Andy78
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    Andy78 Trusted Advisor

    Location:
    Kingston upon Hull
    Hahahaha can just imagine that. One for each flat :D
     
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  41. Ian1981
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    Ian1981 Electrician's Arms

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    North east
    The incoming earth
    depends if each flat has an individual supply through their own meter and not one large incoming cable supplying a bemco.
     
  42. Flanders
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    Flanders Regular EF Member

    Location:
    Tamworth
    Yes i guess your right ,
    Smoke detectors
    Intruder alarm
    Water heater
    Door bell
     
  43. davesparks
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    davesparks Trusted Advisor

    Location:
    guildford
    Yes, just like you see with main bonds to gas meters 'cos it has to be at the meter'
     
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  44. Andy78
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    Andy78 Trusted Advisor

    Location:
    Kingston upon Hull
    Cooker circuit, electric heaters, distribution circuits to outbuildings, boilers ........

    I reckon if you tried you could easily design a domestic install without a single RCD in the CU.
     
  45. Ian1981
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    Ian1981 Electrician's Arms

    Location:
    North east
    How each circuit in the bathroom has to be rcd protected
     
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