tn-s

tn-s

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  1. A

    What kind of earthing is this? TN-S?

  2. J

    ADVICE ON TT OR TN-S FOR OUTSIDE SOLAR CABINET

    Please see attached diagram, can someone advise on if this TT connection is correct for an outside solar metal enclosure as shown in the diagram? If not what are your recommendations on how you would do this please?
  3. Z

    Main earth size on TN-S

    Hi guys. I was on EICR yesterday, where i found that the main earthing conductor is with very small csa- no more than 2.5cm2. Also they run the wire directly behind the CU, where it is twisted with 10mm2 and continues to the MET inside the board. Ze at the board is 0.28 ohms and seems to be ok...
  4. D

    UK Where are the TN-S generators?

    Hi all, I've recently had 2 customers enquire about installing a backup generator for their domestic premises. After a lot of research, contacting generator manufacturers, and generally going around in circles, it's become apparent that TN-S, or "centre tap earth" generators are practically...
  5. impish15

    UK Black cable off supplier's incoming cable?

    Hi, Any suggestions what this black cable is coming off the supply's incoming cable? Its a TN-S system, I thought it could be the earth conductor but the cable is black not green/yellow, plus it looks much smaller than 10mm2 plus there is already an earthing conductor coming off the sheath...
  6. B

    TN-S High Ze measured 3 wire no trip.

    Hi knowledgeable collective. To the chase. TN-S Megger 1553 2 wire Ze 0.09 but was getting Zs on cooker cable 1.5 metre long using No trip 3 wire got 33.4ohms So went back through system right to isolator post meter and was still getting 33 ohm reading. So 2 wire uses higher current so might...
  7. S

    TN-S earthing query

    Hi everyone, This might be a silly question but I have been asked to look at job where they would like a new garage supply, its a old property with the re-wireable fuse board but previously someone has tapped off the meter to an additional RCD unit which was used for a shower (no longer...
  8. G

    PME, TN-S ??

    Hi, a customers earthing arrangement in TN-S. Main earthing conductor 6mm and clamped (loosely) onto outside of supply cable. Having spoken to DNO regarding this they email me saying they will send someone to see if PME is available. The email states PME is the ONLY way they provide an earth...
  9. KevinH

    TN-S earthing issue

    I have just carried out an EICR at an old property and found this issue with the main earthing conductor. It has a TN-S system but the earthing conductor emerging from within the taped up tar coating just before the cut out is only 4mm2 of (what looks like) steel wire armourings. It is 100mm...
  10. B

    Ze=1.87 TT or TN-S?

    Morning all, Looking for some opinions MK Sentry Dual RCD 63/30 CU Fluke 1662 readings... 2 lead hi current Ze= 1.87 Ohms PEFC = 6A PSCC = 0.774kA 3 Lead no trip Ze = 12.95 Ohms Zs at cooker/sockets = 12.56 RCD times are compliant No electrode visible and Gas & H2O 10 mm at board...
  11. M

    House Earthing TN-S or TT....

    ....TN-S appears outside, butt TT employed inside. Good Evening Everybody (This is my first post) Overview: The supply to my parent's cottage consist of an overhead line of three individual cables. Originally, the supply drop from the final pole to the house also consisted of three cables...
  12. P

    When TN-S is TN-C-S

    On another thread there was chat about the N-E voltage to be expected, so I decided to measure my flat out of curiosity as it appears to be TN-S. A brief history - my flat is a Victorian built 4+4 arrangement and when I moved in many years ago each flat was fed by MICC cables. Something like a...
  13. M

    Earth fault on a TN-S system

    So here is the situation 22kV/415V delta-star transformer with neutral point earthed on secondary Downstream breaker of transformer 630A with earth fault setting 0.2xIn @ 100ms This supplues a number of outgoing loads with respective 50A breakers which only have thermal and magnetic settings. An...
  14. C

    Earth Rods in TN-C-S and TN-S

    Why aren't earth rods required on a TN-C-S or TN-S supply? In the US earth rods are mandatory for both. Two earth rods if the first one is over 25 ohms. Here is how its typically done: View: https://youtu.be/4vxYXzNtE9A?t=3459 #6 copper (13.3mm2) is run from the neutral bar of the first...
  15. T

    TN-S braiding

    I don't get involved with a lot of properties that have a TN-S supply but had one today in an old local community theatre/centre had a MET with all sub-main earths etc going to it 16mm/10mm then abrade going from the sheath to the MET all standard and in good condition just looked to me a bit...
  16. C

    6mm earth tn-s question

    Hello guys After doing the adiabatic the 6mm will be fine as the main earth on a tn-s 60a 16mm tail fuse board. Is there any reason past the Calc this may not be ok as running a new earth may be tricky
  17. Andy-1960

    TN-S vs TNC-S (PNB) Earthing System

    What are the thoughts of you guys on the differences between a TN-S and a TNC-S (PNB) Earthing System. My understanding is as follows: TNC-S (PNB) - the Neutral & Earth Conductor are joined in the main switchboard with the neutral conductor between the transformer and the switchboard then...
  18. M

    Earth clamp for TN-S lead sheath supply cable

    Hi Does anyone know where you can purchase the earth clamps that the DNO use on their lead supply cables? I used to have a few but cant find them anymore and Im not sure of the correct name for them. Cheers Martin
  19. J

    After some advise please- Tn-s earth arrangement

    Evening all, Just after some info on the photo attached. It’s a tn-s system with an Earth going to the cu met from under the floor boards. After lifting the boards I found the earth attached as so... I was expecting to see a clamp around the supply cable, not a choc block with legs of unknown...
  20. TonyJohnson

    TN-S or TN-C-S From this photo

    Hi, I undertsand this to be a TN-S system as the earthing arrangement comes along the SWA metal sheath surround but the Ze i got is 0.19 which falls out side the regs of 0.8. Chameleon Electrical -...

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