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EV Charger TT arrangements for private drive close to highway apparatus

Larryinplymouth

Hi All.

I have a situation where a resident has requested the installation of an EV Charger to their domestic premises which has a driveway.

The company installing (Large well known French energy provider) has refused to install the EV Charger as they have identified that there is a street lighting column located within 2.5m of the driveway with a PME service installed.

Whenever we have EV CHargers installed on the Highway we use a TT service and any associated street furniture located within 2.5m of the parking bay is also converted to a TT system. However - as this is a private household and the street light is already in situ it has caused an issue.

I have read the BS7671, 4th Edition of the Electric Vehicle Charging Equipment Installation and other relevant documentation but this apparently seems to be omitted from all publications. (Or have I missed something?)....  This is the first instance we have received of this nature but no doubt it will not be the last.

Any advice / comments welcommed.

Regards

Parents
  • 0

    The situation is not "omitted" from the 4th Edition of the EV CoP ... it is covered. The situation is discussed in the 4th Ed CoP - see section 5.1.2, item (a). BS 7671, Regulation 411.3.1.1, requires simultaneously-accessible exposed-conductive-parts to be connected to the same earthing system. The risk assessment for simultaneous contact (Annex B for Dwellings) was introduced in earlier Editions of the EV CoP to help identify this safety issue, and on page 50 there is a discussion in item (b) of Section 6.8 on the simultaneous contact issue. The first of the Notes on Page 50 (mi highlight) says:

    When assessing the risks of simultaneous contact between conductive-parts
    in contact with different earthing systems within items (a), (b) and (c)
    above, this assessment must include all accessible conductive-parts including,
    for example, any conductive-parts associated with adjoining or nearby
    properties, and any other outdoor-installed electrical equipment, etc.

    Because in this case, the lamp post is part of another installation that is outside the control of the owner of the installation to which the EV charging equipment is to be connected, of course as you point out it's not possible to use TT in this instance, unless some barrier, fence, or other means could be installed on the consumer's side of the boundary to prevent simultaneous contact with both the vehicle body and the lamp post, see 6.8(b)(ii).

    Where an installation has a PME supply (see Section 5.3 of the 4th Ed CoP), the use of a separate TT earthing arrangement for the charging equipment (section 5.3.3) is only one option. There are other design choices to explore, such as provision of electrical separation (section 5.3.4) or use of equipment that detects open-circuit PEN conductor faults (section 5.3.5).

  • 0 in reply to gkenyon

    Yes, this is the perfect install for the type of EV charger that has Open Pen Detection. 

    I think that all Manufacturers will be going down this route within the next year (certainly for domestic customers), and doing away with the TT install for the charger.

  • 0 in reply to gkenyon

    Graham, thanks for the detailled response.... I must admit I had glossed over that!....  We can assist by converting the street light to a TT system of earthing but obviously the client would have to pay for such modifications. Usually whenever we install EV Chargers on the highway we convert anything within 2.5m of the parking bay to TT which includes any electrical apparatus located on the highway as per the CoP.

  • 0 in reply to alanblaby

    We have an issue as the local DNO, who do not currently recognise anything but the TT method of earthing arrangement for these installations. WPD seem to be the most pre-active across the other regions, embracing new Open Pen Conductor technologies.

Reply
  • 0 in reply to alanblaby

    We have an issue as the local DNO, who do not currently recognise anything but the TT method of earthing arrangement for these installations. WPD seem to be the most pre-active across the other regions, embracing new Open Pen Conductor technologies.

Children
  • 0 in reply to Larryinplymouth

    It sounds like the answer is to find another installer who will install a modern charger with open PEN detection.  Get an installer who can self-certify, so they will generate the correct paperwork.  The customer is happy, the council's building control department are happy.  And don't ask anyone for permission first.

  • 0 in reply to Larryinplymouth

    We have an issue as the local DNO, who do not currently recognise anything but the TT method of earthing

    Might be worth a challenge ... it seems to me a DNO would be on a sticky wicket refusing a supply to an installation that complied with current 'British Standard Requirements' as the ESQCR puts it (i.e. BS 7671).

       - Andy.

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