Which earthing system?

Discussion in 'Electricians' Talk' started by HaveAGoButNoHero, Dec 20, 2013.

  1. HI folks, trying to get an electrician to come to the back of beyond is proving difficult, so in the meantime I am trying to understand the set-up at my place, and do some minor repairs where possible. I recently raised the garden sheds issue on this forum, and through you I found out that it is rather too complicated for me to do much right now, hence me phoning a few electricians... While I'm waiting, can anyone advise me on the likely earthing system employed here by looking at these photos please? Many thanks for your time.

    First pic is of pole across road from house, has a transformer, then two wires feed from it (left). Second, pole in garden. Third, earthing wire down pole. 4. cables into house. 5. Meter etc. The red tape I put into cover the exposed copper on the cables that feed into and out of the meter!!!!!!!!!! I am worried that my son might poke something at it.

    Attached Files:

  2. seneca

    seneca Screwfix Select

    From the photos I would say your earthing system is TT. Can you see an earth rod anywhere? It looks as though the network is set up for TNCS judging by the earthing cable running down the pole but I don't think your installation is set-up for that otherwise there would be an earthing conductor coming from the suppliers neutral and going onto your earth terminal.
    FatHands likes this.
  3. hi seneca. There is no sign of an earth rod. If it is TT, system should have RCD protection? All that currently exists on the CU is a MK LN5500 100A main switch,and a bank of MCBs.
  4. seneca

    seneca Screwfix Select

    Yes if it is TT it should definitely have an rcd although it's surprising how many don't, I came across one last week!
  5. seneca

    seneca Screwfix Select

    I can see a third wire connected to the suppliers termination outside so i'm wondering whether they've supplied an earth back to the pole from there, very unconventional if so but possible I suppose because there's also a third wire leaving the house.
  6. seneca

    seneca Screwfix Select

    Out of interest, what area are you in?
  7. could you recommend one please? The other MCBs are: one 40, numerous 32s, a couple each of 16s and 6s. All are MKs. Space for two more. Where would I fit the RCD on the bar?

    The sheds that I posted a question about a few days ago are only "protected" by a 16A MCB! I was thinking of trying to replace it with a suitable RCBO. Although there are 4 double sockets and three flourescent lights in the large shed, I would only be using one power tool at a time, say a bench saw at worst.

    Sorry for questions, I want to make the place as safe as possible, but can't afford an emergzncy callout. We're miles from anywhere, and I know that electricians like to tie numerous jobs together up here (don't know why, they could include travelling time in their bill).
  8. Thurso, north Scotland. Sorry, you'd posted two more b4 I had replied!
  9. That's what I was wondering, two wires come in to the garden pole,where a third one then comes down to earth, and of course back to (from) the house. DOES THIS CHANGE YOUR VIEW ON EARTHING SYSTEM? Sorry about capitals, shift key sticks!
  10. seneca

    seneca Screwfix Select

    I think you do have an earth going back to the pole, as I said very unconventional (in England) but maybe things are done differently up your way. I expect someone else will be along soon to give their views.
  11. Okay, thanks. Nice mo'cycle by the way, I've seen in your previous posts that you do ride it. Thurso is at the eastern end of some rather nice biking roads. You'd like it up here!
  12. seneca

    seneca Screwfix Select

    Yes i'm beginning to think it's TNCS but instead of connecting your earth to their neutral at their cut-out they've done it at the pole, seems a very odd way of doing it but there again I only have experience of my part of the world! (SE England)
  13. seneca

    seneca Screwfix Select

    Thanks, yes I've heard there are some nice biking roads up there.
  14. Thought I'd show you my allegiance to the biking fraternity by way of my avatar! Triumph Speed Triple. Beginning to think I'll have to sell it to pay the electrician that sorts this place out!
  15. seneca

    seneca Screwfix Select

    The Speed Triple is a nice bike, several of the chaps in my local IAM group have them, have only ever heard good reports about them.
  16. Yeah, it is nice, certainly for "playing" about, but in all honesty, when I have done the trip down to Edinburgh Triumph for servicing, I've missed having a faired bike. My neck muscles ain't what they used to be! I did the IAM motorcycling test down in East Sussex some years ago, really enjoyed the training - still keeps me accident-free today.
  17. I don't suppose there's a test that could be done using a simple multimeter that would distinguish the earthing method? Anything else to look for?
  18. seneca

    seneca Screwfix Select

    So you're a fellow IAM member,that's good, it's a pity more don't do it. I only done my IAM test last year after biking for over 50 years! I done my car IAM back in the seventies but never got around to the bike one until last year. What happened was I done the police "Bikesafe" day with my son and got such a ribbing by the coppers that i'd done the car test and not the bike one that I just had to get on with it, very good fun doing the training and I was quite surprised at their emphasis on "making progress", it felt bloody dangerous to me at the speeds they expected on some of the B roads!
  19. seneca

    seneca Screwfix Select

    An earth loop impedance tester would be the only fairly certain way of telling.
  20. Yeah, I remember going fast with police IAM trainers. But the fastest I ever rode down there was on a "road test" of Kawasaki's then new ZX9, accompanied, or rather led, by local bike cops. I SAW STARS THAT DAY! Amazing acceleration, even though I owned a ZZR 1100 at the time! Anyway, I don't know how the police got the on-duty chaps to turn a blind eye!

    As an aside from mo'bikes, can anyone tell me what this ancient switching unit might have been for? Situated up above one of the kitchen doors (out of reach of children perhaps), and covered in old chip fat, It presently isolates the immersion heater - I don't know what "small" and "large" refer to (although I'm sure it'll be obvious when someone tells me!). I'm assuming I can replace it with a cooker isolating switch or similar, horizontally though to avoid having to redecorate! Thanks.

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    Last edited: Dec 20, 2013

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