Which earthing system?

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

  1. seneca

    seneca Screwfix Select

    No i've never seen one of those before, I wonder if it switched two immersion heaters, they often had a tank with two immersion heaters in, one was low down in the tank and the other nearer to the top. The switch was marked bath and sink, the lower one heated the whole tank for bath use and the other just heated the upper part which was used just for sink use. Maybe small referred to a small amount of heated water and large for the whole tankful?
     
  2. okay, thanks seneca. I have just been looking through an old "Home Electrics" book of 1984 vintage, and looked up immersion heaters, to find exactly that, two heaters in a tank, upper and lower, although this doesn't mention sink and bath, but rather off peak electricity for one and the other on the "24 hour circuit". Not clear to me how that would work. I will look behind it to see what kind of a wiring mess there is - no doubt one unused circuit is still sitting there! Will fit a modern one.
     
  3. mr reflex

    mr reflex Member


    Miles from anywhere..... fair play to you but choosing to stay in an exclusive/remote area will indeed attract exclusive/remote charges.....!
     
  4. Sean_ork

    Sean_ork Screwfix Select

    Thurso ''exclusive'' :)
     
  5. Lectrician

    Lectrician Screwfix Select

    All supplies will have the TX earthed down the pole. The neutral of any TX will always be tied to earth, regardless of earthing system.

    It looks like an old TN-S to me. Separate overhead earth (no longer done). You could report lack of earthing and see if they will replace your aged supply with a SPLIT concentric drop (TN-S)
     
    FatHands likes this.
  6. I appreciate that mr reflex, and I'm certainly happy to pay the extra for travelling time etc. As for exclusive, it's all relative - run down old croft houses dominate here (actually 20 miles or so west of the hustle and bustle (ha ha) of Thurso, on a single track road), but compared to Wick, some might say this area is upperclass!
     
    Last edited: Dec 21, 2013

  7. Okay, thank you for that Lectrician, I will contact the electricity company. In the meantime, is there anything I could do by way of replacing MCBs? With RCBOs? The CU is a tall one, I think RCBOs would fit, I've yet to remove the cover. Or additional RCDs - the CU has two unused ways. Sorry for the undoubtedly silly questions, but I just want to keep my family safe now that I know things aren't right!
     
  8. Hi folks. I am waiting to hear back from my electricity supplier about the earthing system here. In the meantime, I had a look in the CU. Split N bar, but linked to one again, no RCDs either side. But of greater interest, I think, is the huge N wire on the left. Anyone have any idea what this signifies please? Thank you.
     

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  9. stateit

    stateit Screwfix Select

    Hi HaveAGo,

    As said above - unconventional earthing system. I'd say it's a type of TN-C-S but I'd treat it as TT and have an earth rod in there (the Main Earth looks only about 6mm c.s.a.cable)

    As for the 'small & large' : I saw my very first one of those a couple of weeks ago. It did supply the immersion - presumably 'large' for full heat (large element - overnight) and 'small' for top-up (smaller element - daytime). For use when you didn't have had a timer (on-peak/off-paek timer) controlling the different element switching. Which if you don't I'd strongly suggest getting. In my customer's case, gas came to their street a couple of decades ago so immersion elements aren't their source of hot water now - except as a backup.
     
  10. Sean_ork

    Sean_ork Screwfix Select

    Most of Caithness and the surrounding is supplied like this, as is nearly all up here - it works and it's very reliable so unless there's a new development, or a project to upgrade the distribution to a number of properties at the same time there's a good chance that's how it will stay for a long while yet. SSE have the ''if it's not broke we won't fix it'' attitude to upgrading their local distribution - the consumer unit looks to be in good order, but not current (which doesn't mean it's unsafe)

    It's certainly worth contacting your supplier as they are keen to replace those rotary meters, and will provide you with a new fuse carrier, and isolator - at no cost.

    some say a 90 minutes trip further North is properly exclusive
     
  11. Lectrician

    Lectrician Screwfix Select

    TN-S supplies with a separate overhead earth are susceptible to loosing the earth, and no one being aware. It only takes a little corrosion.

    DNOs are in the process of slowly removing un insulated overhead LV lines too, although yours does looked sleeved, although not at the terminations. I believe there is a target date for this, but sure it was extended.
     
  12. Thank you very much for this folks. Can I demand that the company to check the earthing then? Or must I have specific reason to ask, i.e. fear of being electrocuted isn't enough?! I will certainly ask them to replace the meter etc.

    Assuming the electric company won't do very much outside for now then, and assuming worst case scenario of no or poor earth connection, and that having a rod installed might take a few weeks (finding someone to do it, I mean), would it be worth popping an RCBO or two in, on any circuits in particular?

    Sean_ork - I don't suppose you'll be passing this way some time soon? To remind yourself how the less-fortunate (i.e. 90 mins further south) live?!! You could pop in for tea and a natter and give me a few pointers so that I am well-versed when it comes to "instructing" an electrician!
     
  13. Thanks for this Lectrician. It's a rare piece then, if you professionals haven't seen the likes of them before! Our main heating is via Calor gas now, the immersion heater isn't used very often - it has a single large element fed in at the top of the tank. I looked behind the switching unit today, and found that the small and large switch is still connected. I dread to think where the other end is located, live, because it isn't obvious at the tank end.
     
  14. Sean_ork

    Sean_ork Screwfix Select

    thanks for the offer, I'm not an electrician, but I do have a NAPIT badge ;)
     
  15. wally

    wally Screwfix Select

    Have not read all the posts but I think sens answer is what I would have thought about that old switch with a setting for small & large. Rather than a standard immersion tank I would take it a bit further & think the heater could have been a UDB heater. I think Sadia used to make them & they were fully enclosed something like a megaflow nowadays. UDB = under draining board heater. They used to last for years, the elements were wire wound & used to slide into a tube so no draining down. I don't think they make them now although I did fit the whole thing as a replacement about 15 years or so ago.
     
  16. Hi Wally. It could have been, however it currently operates the immersion heater, upstairs. The house was built in 1890s, and has a 1960 "modern" extension, and the electrics seem "all over the place" (modernisation more recently has made it messy, I think), with surprises popping up here and there, so what you suggest could be the case!
     
  17. Okay, ta. Thought i'd be cheeky and ask! But if you're ever in Strath Halladale, feel free to pop in - "Ardachadh", about 4 miles south of north coast road. We don't have to talk electrics.
     
  18. wally

    wally Screwfix Select

    Not my area mate, I'm in silly suffolk & only work now & again as I'm partly retired at 67. Mind you since xmas eve Ive had severe backache & not even being able to lift the chicken in/out of oven, hobling about with a walking stick at the mo
     
  19. Sean_ork

    Sean_ork Screwfix Select

    I try and avoid crossing the Firth too often these days, but will remember your offer. You've picked a great place to live, I hope you've explored that west coast road, along through to Betty Hill etc I suspect they knew bikes were going to be invented when they set down the route for it - stunning one minute, bleak and dangerous the next
     
  20. you're doing well, i'm 20 years your junior and my back and shoulders are almost wrecked. Passing things on and off boats did me in!
     

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