Wiring Centre Mess

Discussion in 'Electricians' Talk' started by realloser, Nov 27, 2022.

  1. realloser

    realloser New Member

    I purchased a Hive smart thermostat recently and it looked quite straightforward to install. I'm reasonably competant with plumbing and electrics, nothing too critical. However, when I checked our existing thermostat backplate the wiring didn't look as I expected??
    When I looked at the wiring centre it looked like this.

    Any suggestions?
  2. dai.versity

    dai.versity Active Member

    All looks pretty standard to me
    Abbadon2001 likes this.
  3. arrow

    arrow Active Member

    Standard does not include earth wires getting used as lives. That needs sorting out and rewired, as it is a cowboy bodge.
    Abbadon2001 likes this.
  4. Bazza

    Bazza Screwfix Select

    Standard plumber fare. We love them. Little treasures (should be buried)
  5. dai.versity

    dai.versity Active Member

    Explain that comment
  6. arrow

    arrow Active Member

    It is self explanatory.
  7. dai.versity

    dai.versity Active Member

    Ok, so you can't explain, no problem
  8. Bazza

    Bazza Screwfix Select

    Terminal 4 has a Conductor in it which has green&yellow sleeving.
    As you may remember, green&yellow means the wire is (and must be) used as an earth connection.
    Whoever wired this is using the wire that must be an earth as a live conductor. Probably call for heat, or something like that. That’s not allowed.
    So, the wiring should be condemned and rewired properly.
  9. arrow

    arrow Active Member

    I do not need to reply to condescending posts, when you knew exactly what was getting described.
  10. Bazza-spark

    Bazza-spark Screwfix Select

    Looking at the wiring in the stat I would think that it is call for heat as @Bazza says.
    dai.versity likes this.
  11. dai.versity

    dai.versity Active Member

    Yes, never noticed that
  12. realloser

    realloser New Member

    I've just noticed that there is an earth wire at terminal 4 of the Wiring Centre??

    Silly question but should I be looking for an electricion or a plumber to sort this out? Any ideas on how much this is liable to cost?
  13. Tony Goddard

    Tony Goddard Screwfix Select

    Its not an earth, but rather a green and yellow re-purposed as a live as discussed above. Green & Yellow is reserved for earth only, so that cable needs replacing with one with enough live cores or another cable running to give the extra required live.

    Ideally an electrician, but many for some reason won't touch heating controls - I'm one of the few round here, for example, who does, get a lot of referrals from other sparks!! or a plumber who knows what they are doing - if you can get an extra cable in yourself its an easy enough job.
  14. Bazza

    Bazza Screwfix Select

    As above. I’d suspect that sin was committed by a plumber. I'd not be seeking the problem to be properly dealt with by another one.

    As Yoda might say 4922B3EE-B19E-4AC9-8987-522C961E669E.jpeg
    Tony Goddard likes this.
  15. realloser

    realloser New Member

    Thanks guys for your help. Every time I look at these pictures I notice something new!?
    The cable into the back plate is 5 core, good. But then two black cables both go the same terminal, the 5th one along, and the green/yellow cable to the 6th terminal along. So theres a black cable that could have been used for a live but the green/yellow has been used instead. This looks like madness?? I think that I'd better get an electrician to look at this.
  16. MGW

    MGW Screwfix Select

    I had the same problem, wanted to control domestic hot water (DHW) and central heating (CH) from main house, there was a three core and earth cable, and one core open circuit, and it changed colours from red, yellow, blue one end to brown, black, grey the other end, so clearly some hidden junction.

    My cure was to use Nest Gen 3, so the two wires could control both DHW and CH and keep the control module/wall thermostat battery charged. Maybe not best method, as Nest will not link to TRV's, but it got me around the problem, and also happier using 12 volt when one core is open and not a clue where joined.

    I also had a wiring mess, when I moved in to turn on central heating I had to go outside down a set of steps, and into the flat and manually plug in the pump and turn on boiler, no thermostat in main house.

    Since I am an electrician I was able to find a way around the problem, but it was not easy, and the heating engineer admitted he had no idea how to wire it up.

    The combi boiler has made things easy, the manufacturer does all the clever wiring, but the older system was likely the most complex wiring found in any home.

    I hate domestic, as every Tom Dick or Harry has a go. So missing ID's on wires, and earth marked wires used as live, and no HSE to stop it. Industrially no unqualified would dream of working on electrics, and every job would have paperwork raised and plans submitted or altered so one could see what had been done.

    The Part P was an attempt to stop the cowboys, mainly kitchen fitters, but also plumbers, but in England it has been near enough dropped, as what I resulted in was the reverse to what was wanted, we got less paperwork, as people did work they did not want to admit doing.

    However the regulations state
    The problem is it says "single-core" and people seem to ignore the full stop after purpose. So they think they can over sleeve the green-and-yellow. The regulation 514.4.3 is to do with a PEN which is not permitted except for the supply network, so you can ignore that bit.

    The other bit is
    so since 1966 we have to run an earth to any installation (not portable stuff where it is class II) even if the item is class II and does not need an earth. Before 1966 often lights had no earths, but you needed an earth with fluorescent tubes, so there was a problem when changing lamp type to fluorescent, so rules were changed.

    I want to have better control on my DHW but there is no tank thermostat, and no way to run cables to where boiler it, and expensive to use wireless. But some times no option.
  17. Davie

    Davie Member

    I have three zone valves so my wiring centre was even more congested. I sorted it by wiring the three zone valves into a standard Wago 24-terminal wiring box and taking just one call for heat out of that to the wiring centre. Reduced the number of wires going into the wiring centre by 10. Also makes replacing the zone valve motors a doddle.
  18. The Happy Builder

    The Happy Builder Screwfix Select

    Using a green/yellow earth conductor as a live conductor is not acceptable, not even if the ends are over sleeved.

    The installation is sub-standard and not fit for purpose, it needs ripping apart and rewiring to install the new controls.
  19. MGW

    MGW Screwfix Select

    In some ways I agree, but what do you think are the chances of getting some one back to correct their error in using green/yellow as a live?

    If short run OK, but this house with flooring made with sheets of board not normal floor boards, that would be near impossible.
  20. The Happy Builder

    The Happy Builder Screwfix Select

    Not using green/yellow insulated conductors as a live is something that has been clarified in the BS7671 18th edition amendment two, however in this particular instance it looks like there’s two black conductors doubled up and connected to the same terminal, so the person who did the wiring appears to be totally incompetent, because using the green/yellow as a live wasn’t even required as there was enough live conductors without doing so.

    It all just needs rewiring, though it may actually be possible to reuse the existing cables.

    There is no point in messing about, just rewire it as that is the only sensible way forward.

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