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DISTRIBUTOR CANNOT BE TRUSTED...

Former Community Member
Former Community Member
Hi folks!


This is my first forum post and hopefully and interesting topic. I am looking for some advice on where to start!

Background:
  1. 4th floor apartment tear-out in the city of Baku, Azerbaijan in a very old Soviet-era building block with unknown amounts of modifications.

  • 4 wire system (3-phase and neutral) entering and distributed throughout the building (no armoured cable / no separate earth).

  • No enforced local regulations as the general wiring in the city is a free-for-all (I am told it should be to PUE 6 standard). I could share many examples but this is not the aim of this post!

  • No building plans available from the council / no wiring / single-line diagrams available for the building or from the distributor.

  • No option available for a reliable survey - Partly being that most of the local electricians think that an earth core is a waste of money!

  • Basically the local distributor cannot be relied upon as can be seen by the photo example of the electrical panel closest to the apartment from the local government electrical company...

  • I am an electrical engineer wanting to get my hands dirty with my own project compliant to the BS 7671 wiring regs. I will design the domestic electrical installation and will have it verified by an (UK) electrician / expat before proceeding and sourcing materials.

Aim:


  1. Brand new domestic apartment electrical installation to BS 7671 18th Edition in which is in my control (full rewire, new consumer unit etc.). BS exceed the local regulations.

  • Keep politics / what-should-be for the incoming panel out of the discussion, it is what it is and there is not much I can do except wait decades for regulations and enforcements to catch up!

  • Provide the safest solution to protect my family without running away from the building / country.

Closest Panel to my Apartment:

  • Ok lets cut to the chase - this may just be the worst panel that you have ever seen however I cannot modify it as it is owned by the local government electrical company. It gets no points for compliance to any regulation (maybe 1 for being metal only!). I unfortunately has to live with this monstrosity until the building is knocked down in the future (and this is one of the newer / better panels in the building believe it or not…1 of 3 panels up to the apartment).

34853545ae5c04645e1bb134ec9267e3-img_1749.pdf


Queries:

  1. Can I assume that the incoming supply is a TN-C-S (and I know this is the distributors responsibility…) i.e. connect the MET and neutral together before the consumer panel? I know we should never assume so what is the best way to test? I am trying to source a Megger. My concern is that this could bypass some protection elsewhere in the building although it appears to have only overcurrent protection (fuses).

  • Should I have a dedicated earth run from the incoming of the building (from the neutral bar) up to the apartment consumer unit instead? My concern is that there my be a potential difference between the neutral and the earth at the apartment which could require 2P RCBOs throughout. Yes there should not be a potential difference however there is a lot of twisted wiring (junction boxes are a luxury…) and poor looking connections as well as all the apartment neutrals connected together in the block.

  • A third option would be to have an earth pit installed in the car park and run the dedicated earth to the MET in the apartment although 2P RCBOs may still be required.



Any assistance is greatly appreciated including verification / testing methods before I dive into the design of the consumer unit. Thank you in advance,


Chris
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  • Former Community Member
    0 Former Community Member
    UPDATES   (to Pandora's box)


    Busy period now finished - heavy renovation works well underway. An electrician also opened the main and sub main panels. 

    A picture is worth a thousand words... (and is also a good excuse to learn some AutoCAD!):
     




     

    Main Building DB

    1.jpeg
    2.jpeg
    3.jpeg   The neutral bar is not looking healthy at all. First time I have seen DB conductors just wrapped around each other, obviously not a good connection from the melted insulation.
    4.jpeg   The yellow core of this old 4 core cable looks like it could go out to an earth electrode however this is just an assumption.




    Sub-Main DB


    5.jpeg
    6.jpeg   More twisted together neutral connections.
    7.jpeg   The neutrals connect to the DB earth boss.




    In summary, a broken neutral is very possible at multiple points in the building or at least with a bad connection.


     


    1. To make it more interesting, there is a ground-level water pump, only for the flat in question (one pump per flat). I am considering to isolate the pipework prior to the pump to make a TT earth system from the earth electrode only i.e. isolate all extraneous pipework via isolation flanges and converting to plastic prior to entering the apartment.   8.jpeg

    • Another reason for this is that the metal gas main that runs around the outside of the building to a lot of flats is connecting to a lot of combi boilers. This is basically their only earth connection.

    • Rebar could be connected to within the building concrete works / last electrical panel. I doubt there is any deliberate electrical continuity during the building construction such as copper rods in the foundation piles / clamps to maintain electrical continuity throughout. There is only the steel ties between the rebar which would still form a connection of sorts. Interestingly though that the local electricians would appear to connect to it on the last panel as previously highlighted.   9.jpeg



    Queries
    1. Can rebar encased in concrete be used as the sole earth electrode for the flat? I am trying to get a loop tester in country so I can check it first. I guess the rebar (assuming it is electrically continuous) would be classed as an extraneous conductor. Just curious as this could avoid the issues below.

    • It will be near impossible to install a new TT earth electrode in the car park / yard away from underground metalwork. I need to continue my homework on rebar electrodes and distances away from other buried services. Would it be such an issue in a flat with no extraneous connections for the TT earth electrode to be in close proximity to buried metal work? If a fault from another system were to raise the ground potential then all the exposed metalwork in the flat should also raise to the same potential i.e. no potential difference between exposed metalwork within the flat.


    Thank you in advance,


    Chris
Reply
  • Former Community Member
    0 Former Community Member
    UPDATES   (to Pandora's box)


    Busy period now finished - heavy renovation works well underway. An electrician also opened the main and sub main panels. 

    A picture is worth a thousand words... (and is also a good excuse to learn some AutoCAD!):
     




     

    Main Building DB

    1.jpeg
    2.jpeg
    3.jpeg   The neutral bar is not looking healthy at all. First time I have seen DB conductors just wrapped around each other, obviously not a good connection from the melted insulation.
    4.jpeg   The yellow core of this old 4 core cable looks like it could go out to an earth electrode however this is just an assumption.




    Sub-Main DB


    5.jpeg
    6.jpeg   More twisted together neutral connections.
    7.jpeg   The neutrals connect to the DB earth boss.




    In summary, a broken neutral is very possible at multiple points in the building or at least with a bad connection.


     


    1. To make it more interesting, there is a ground-level water pump, only for the flat in question (one pump per flat). I am considering to isolate the pipework prior to the pump to make a TT earth system from the earth electrode only i.e. isolate all extraneous pipework via isolation flanges and converting to plastic prior to entering the apartment.   8.jpeg

    • Another reason for this is that the metal gas main that runs around the outside of the building to a lot of flats is connecting to a lot of combi boilers. This is basically their only earth connection.

    • Rebar could be connected to within the building concrete works / last electrical panel. I doubt there is any deliberate electrical continuity during the building construction such as copper rods in the foundation piles / clamps to maintain electrical continuity throughout. There is only the steel ties between the rebar which would still form a connection of sorts. Interestingly though that the local electricians would appear to connect to it on the last panel as previously highlighted.   9.jpeg



    Queries
    1. Can rebar encased in concrete be used as the sole earth electrode for the flat? I am trying to get a loop tester in country so I can check it first. I guess the rebar (assuming it is electrically continuous) would be classed as an extraneous conductor. Just curious as this could avoid the issues below.

    • It will be near impossible to install a new TT earth electrode in the car park / yard away from underground metalwork. I need to continue my homework on rebar electrodes and distances away from other buried services. Would it be such an issue in a flat with no extraneous connections for the TT earth electrode to be in close proximity to buried metal work? If a fault from another system were to raise the ground potential then all the exposed metalwork in the flat should also raise to the same potential i.e. no potential difference between exposed metalwork within the flat.


    Thank you in advance,


    Chris
Children
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