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Exporting PME to Socket in high street.

M.L.R

Hi All

First time question,

On doing a EICR on a feeder pillar, in a shopping pedestrian high street. Which controls decorative floor recessed lighting and also Ceeform Socket in manholes in the floor. They access sockets by lifting the lid and then plugging into them. They are market traders that use the outlets and plug in various items small and large Class 1, one of the largest items I have seen plugged in is a Stainless steel Fish counter on wheels, Bake potato ovens on steel benches ect. 

The earthing arragement is TNC-s. The panel was contructed by a well know high street furniture panel maker. Wiring may have been done by others. This is a unkown.

All lighting are on MCBs

All sockets on RCBOs 

So I have failed/or going to fail the installation due to exporting the PME to the socket outlets and for others reasons.The reason for this was,upon reading the (Guide-to-highway-electrical-street-furniture section 6). As section 6.5 mention being supplied from a TT system. Also in section 6.11.2. On completion of the construction phase of an installation a full electrical inspection and test must be carried out to confirm that the installation complies with BS 7671 in its entirety but especially to Part 7, Section 708 – Electrical installations in caravan/ camping parks and similar locations as applicable.(aiming this should be TT)

Just for clarifiction, am I missing something.As I could not see the manufacture doing this! If they did do it or I'm missing something. 

If this is true and should have been TT, then raising another issue if changed there could be  2 earth arrangments within arms reach within the High street.Thats for another day.

Look foward to your Input.

Cheers

Mark

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  • 0

    Unless its a domestic caravan, its probably not all that similar. A supply that was real TN-S would be ideal of course but there is almost none of it left in some places.


    Be aware that things like lamp-posts and bus stops and so on in built-up areas are quite commonly fed from PME /TNC-s these days, and while it pains me to say it, in practice they seem to give little trouble - so for example do the floor mounted lights have exposed metal that is on the PME earth ?

    Also note that although the IET guide you refer to implies that connecting PME to a stall is illegal, 

    That actually is not quite what the ESQCR says -rather we have

    The words 'temporary' and "conductive material" do not appear at all in the actual legislation, only in guidance, - so there is no legal prohibition on the use of PME in temporary structures. It may not be a good idea however ;-) and the advice of the guidance is correctly to point that out.

    The problem is , that I fear that  if you wanted to change to TT, you'd have to change everything else in the street as well,  to get far enough away.

    Have you spoken to the makers or tried to get the original installation data ? There may for example be a grid electrode that is connected to the PME earth - which is about the only way you can use PME in a wet environment and be sure what the ground is doing.

    You don't really want to dig things up to see how it was done if possible to avoid that.
    Mike.

    M.

  • 0 in reply to mapj1

    I did send a eamil and they have no data on the project, I can not see a earth electrode, something I did look for on the installation.If you read section 6.3 Section considered Are all one with resitriction with PME! They do not have skill person on hand market day Nor test the Items.So if they can not satifiy anyone of those its a fail. Cheers for the reply

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  • 0 in reply to mapj1

    I did send a eamil and they have no data on the project, I can not see a earth electrode, something I did look for on the installation.If you read section 6.3 Section considered Are all one with resitriction with PME! They do not have skill person on hand market day Nor test the Items.So if they can not satifiy anyone of those its a fail. Cheers for the reply

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