tt system

  1. J

    TT system with No RCD

    Been out to replace an oven on an installation which pre dates the need for RCD's so only has MCB's, the earthing arrangement is TT. As I am only changing the oven this need not be RCD protected but is the maximum Ze still 200ohms?
  2. C

    TT system enquiry

    Hi Guys I have just had a large steel I beam installed across the width of my house and supported by another, do these have to be integrated into the earth bonding or not??? Also I am going to remodel floor plan and was wondering if it is ok to use metal partitioning and if so will this have to...
  3. S

    TT system consumer units

    Hi, I do a lot of work on domestic TT systems. Now that AMD 3 is in force, what are you guys using RCBO's or a 100ma S type main switch for TT earthing systems. Cheers
  4. R

    Metal Clad board on TT system

    Hello all, Currently pricing up a job, which is to install a new ring, light and shower circuit for a small extension. The exsiting board is full so I was considering putting in a second board just for these circuits. After flicking through osg i was going to use a main switch and individual...
  5. C

    Fitting new CU to TT system and old BS fuse box

    Hi there, new to this site and just after a bit of advice. I am part qualified as a Domestic Electrical Installer and am just waiting for the course to complete my Part P. I have been asked to install a new Consumer Unit on a TT system in a very old cottage. As seen in the photographs, the...
  6. S

    tt system question

    Chaps.. Simple question.. Been studying and been reading peoples issues that arise on jobs ect i came across on one where one chap said that a rcd main switch can only be used on a TT system? Is this true and if why?
  7. H

    disconnection times for 100mA BS61008 on a tt system

    Gents, tested a pub split load db today in the sticks. before i commence any work, am i right in stating anything over 0.1 on the 100mA side is a fail? did a test on the man 100mA and its disconnecting in 0.25 I've tested the sockets on the 30mA side and they are disconnecting correctly. Pubs...
  8. M

    Consumer unit upgrade TT system

    Appreciate a bit of advice regarding this that I'm doing in the morning- Consumer unit upgrade in house with 6mm gas & water bonding existing (leaving bonding as it is). Existing rod in house with 6mm up to CU. (Existing install) From a TT system in the house there is a 2.5/1.0 T&E running to...
  9. naylorpd

    Small voltage from neutral to earth on TT system

    I'm building a house in Azerbaijan, with 3 phase mains supply and TT earthing. The main transformer is at least 800m from my house. Whilst doing my final measurements before going live, I noticed a small voltage between neutral and earth. It varies between 2-4V and seems to be AC. It isn't a...
  10. HappyHippyDad

    RCBO's on a TT system.

    Morning all.. I am off sick from work, this rarely happens and already I am bored, so I thought I'd start a thread on the above which i have been thinking about. Question 1: I realise that most on here suggest DP or SPSN RCBO's for a TT, but I am unsure why (with regards the regs)? This is why...
  11. M

    TT system tripping

    I am working on a TT system and the electrics are tripping all the time, I have narrowed it down to the downstairs light circuit. Everytime when this light circuit is connected at the board and if I try to turn the oven (on the cooker circuit) or boil a kettle. ( ring main) it trips the...
  12. S

    TT system converted to PME - Earth rod query

    I've just installed two 100A isolators in a farmbuilding and the nearby house. The earthing arrangements seemed unusual. The power comes in overhead and a single cable drops into the main head. This has PME head and a label on the board stating that there is Protective Multiple Earthing. The...
  13. spud1

    Tails - metal board - TT system

    Hi, Can anyone clarify for me the requirements regarding either the RCD protection of tails or glanding of tails entering a metal consumer unit in a TT system. With specific forethought to the upcoming amendment enforcing all metal consumer units. Cheers
    • spud1
    • Thread
    • amendment board boards insulated metal system tails tt system
    • Replies: 45
    • Forum: UK Electrical Forum
  14. F

    TT system main bonding CSA?

    Rewiring an older TT terraced property. There is currently 6mm earthing from the rod, and also as main bonding to gas and water. I (was!) confident that 6mm main bonding met the requirements of BS7671, but a fellow Part P installer insists that I need to upgrade the main bonding to 10mm, but...
  15. B

    New Consumer Unit on a TT System

    Am I right in saying the Regs for a TT system now say you can have DP main switch with all circuits on a 30mA RCD's (Split Board)?
  16. havo one

    Distribution circuit tt system

    on a TT system today I had meter tails backed up by domestic 100A 88-3 fuse directly into fusebord, no main switch or RCD on tails which is very common in N.I, am I right to consider this as a distribution circuit? my thoughts are that the fuse doesn't provide proper disconnection time and would...
  17. D

    PFC in a TT system

    Hey guys im testing a TT System and the Rod resistance is 33 ohms. Which voltage / 33 is 6.969 which is greater than 6k rated on the mcb. What else can i do except increasing the rated mcb to 10k? thanks in advance.
  18. D

    TT system

    Hi doing a cu change at weekend 8 way dual rcd on a 100amp fuse and first time doing one on a tt system noticed that main bonding looks to be a 6mm and so is bonding to gas and water looked at some posts and people say is ok but regs state 16mm main earth and 10mm bonding do I change it all...
  19. C

    Benefits of a TT system?

    If an installation is supplied by a two wire system (E.G. a TT system) , what are the benefits of using an earth electrode instead of simply joining earth to neutral at the supply head to create a TNCS system? Surely using the supplier's neutral is a more effective return path for fault current...
  20. G

    TT system stand by generator

    Can anyone tell me if a test is to carried out to establish the resistance of earth electrode for a generator providing alternative supply 1)what must be agreed before test can begin? 2)Action to be taken with earthing conductor for generator before testing can began. Action to be taken with...
    • gurungtp
    • Thread
    • before conductor earthing generator question stand system tt system
    • Replies: 8
    • Forum: UK Electrical Forum

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