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Simultaenous Contact

Dom

Good afternoon all, 

I am seeking the collective views of the group regarding the issues we are currently encountering within the EV installation environment in relation to simultaneous contact.

In simple terms, we are seeing a significant number of installations where customers have lamp posts located within their driveways. In many of these cases, it is not possible to achieve the recommended 2.5‑metre separation distance.

My position is that, where physical separation cannot be achieved, the application of layered protection at the EV charge point and associated switchgear would leave the customer in no worse position than prior to the installation. It is accepted that the proposal only outlines protection on the vehicle, but there are no other solutions for industry, are we with the protection detailed taking enough measures to carry out an install and in affect leave the install without a subsantial increase in risk?

My proposed approach to managing simultaneous contact risk would follow a structured hierarchy as set out below:

  • Can the maximum separation distance be achieved?
  • Can barriers or enclosures be installed to prevent simultaneous contact?
  • If neither of the above options are achievable, can layered protection provide an acceptable level of risk mitigation?

With layered protection, the proposed measures would include:

  • Installation of a compliant open‑PEN (O‑PEN) protective device
  • Provision of a double‑pole 30 mA Type A RCBO
  • Use of a charge point - M3 21 mA protection

Based on the above, the assumption is that, if all protective measures are correctly installed and verified, the installation would incorporate:

  • Automatic disconnection within the required times
  • Residual current protection
  • Open‑PEN fault detection

This combination of protections would significantly reduce the likelihood of a fault condition persisting for any meaningful duration.

On this basis, the key question for consideration is:

Where physical separation and barriers are not achievable, would it be considered acceptable to proceed with installation relying on this layered protection approach?

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  • 0
    Dom said:
    My position is that, where physical separation cannot be achieved, the application of layered protection at the EV charge point and associated switchgear would leave the customer in no worse position than prior to the installation. It is accepted that the proposal only outlines protection on the vehicle, but there are no other solutions for industry, are we with the protection detailed taking enough measures to carry out an install and in affect leave the install without a subsantial increase in risk?

    Has this position considered that a fundamental requirement of the effectiveness of protection against electric shock by is that simultaneously-accessible exposed-conductive-parts are connected to the same earthing system (Regulation 411.3.1.1)?

    Basically, if you have a simultaneous contact issue, there is a departure from BS 7671.

    How can you prove your mitigations provide "equivalent safety" to BS 7671 in order that you can make an 'intended departure' ?

    Considering the 'mitigations':

    • Installation of a compliant open‑PEN (O‑PEN) protective device - this would only protect against open-PEN faults, not all conditions that might cause issues for 'simultaneous contact'. 
    • Provision of a double‑pole 30 mA Type A RCBO - this is a requirement of BS 7671 for all EV charging points, and considers you do conform to Regulation 411.3.1.1
    • Use of a charge point - M3 21 mA protection - In IET 01:2024, this is not permitted as a sole means of protection, which it would be if it were operating on a touch-voltage event not related to a PEN fault. In addition, unlike a fault-to-earth via RCD, a person is getting a shock in order for the M3 device to operate. BS 7671 does not recognise this type of device for anything other than that stated in Regulation 722.411.4.1, and certainly not for mitigation against a fundamental requirement of BS 7671.

      Having said that, M3 would be sensible for protection against PEN faults in the lamp-post supply, that would be reflected 'in reverse' on the EV.

    It's worth remembering, that the lamp post might be supplied from a completely separate HV substation ... the fault you're trying to mitigate against here might well be an HV fault, which is way outside the capability of BS 7671 to handle, similarly an OPDD.

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  • 0
    Dom said:
    My position is that, where physical separation cannot be achieved, the application of layered protection at the EV charge point and associated switchgear would leave the customer in no worse position than prior to the installation. It is accepted that the proposal only outlines protection on the vehicle, but there are no other solutions for industry, are we with the protection detailed taking enough measures to carry out an install and in affect leave the install without a subsantial increase in risk?

    Has this position considered that a fundamental requirement of the effectiveness of protection against electric shock by is that simultaneously-accessible exposed-conductive-parts are connected to the same earthing system (Regulation 411.3.1.1)?

    Basically, if you have a simultaneous contact issue, there is a departure from BS 7671.

    How can you prove your mitigations provide "equivalent safety" to BS 7671 in order that you can make an 'intended departure' ?

    Considering the 'mitigations':

    • Installation of a compliant open‑PEN (O‑PEN) protective device - this would only protect against open-PEN faults, not all conditions that might cause issues for 'simultaneous contact'. 
    • Provision of a double‑pole 30 mA Type A RCBO - this is a requirement of BS 7671 for all EV charging points, and considers you do conform to Regulation 411.3.1.1
    • Use of a charge point - M3 21 mA protection - In IET 01:2024, this is not permitted as a sole means of protection, which it would be if it were operating on a touch-voltage event not related to a PEN fault. In addition, unlike a fault-to-earth via RCD, a person is getting a shock in order for the M3 device to operate. BS 7671 does not recognise this type of device for anything other than that stated in Regulation 722.411.4.1, and certainly not for mitigation against a fundamental requirement of BS 7671.

      Having said that, M3 would be sensible for protection against PEN faults in the lamp-post supply, that would be reflected 'in reverse' on the EV.

    It's worth remembering, that the lamp post might be supplied from a completely separate HV substation ... the fault you're trying to mitigate against here might well be an HV fault, which is way outside the capability of BS 7671 to handle, similarly an OPDD.

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  • 0 in reply to gkenyon

    Hi Graham,

    As always, thank you for the insightful response — it’s genuinely appreciated.

    In terms of the points raised, I am trying to establish a practical way forward for the significant number of customers who are currently unable to have EV charge points installed due to simultaneous contact concerns.

    The reality we are facing is that the bonding or linking of earthing between the EV charge point and adjacent street furniture is, in many cases, not practically achievable. This leaves us reliant on DNOs and local authorities to provide a solution, which, at present, is not materialising at the pace or scale required.

    Across our installations, O-PEN protection and double-pole RCBOs are applied as standard. I fully accept your comments regarding M3 protection — they are both fair and technically valid. However, I am consistently seeing installations proceeding in similar scenarios to those described, and my objective is to explore whether a structured, layered protection approach can be applied to minimise risk in situations where compliance through conventional means is not feasible.

    I recognise that this introduces a departure from Regulation 411.3.1.1 in respect to the linking of exposed-conductive-parts. However, given the practical constraints, there are very limited options available that would enable an installation to proceed while remaining commercially and operationally viable.

    I also note that some manufacturers are positioning earth conductor leakage monitoring within their charge points as a means to disregard simultaneous contact risk. My concern is that this appears to be a recharacterisation of M3-type protection and, in isolation, does not seem to provide a fully compliant solution under BS 7671.

    More broadly, the issue is being amplified by the government’s push on off-street parking grants, which is increasing the volume of installations encountering simultaneous contact challenges without a corresponding, standardised industry solution.

    I would welcome your thoughts on whether a clearly defined layered protection model could form part of an interim, risk-managed approach for these scenarios, or whether the position remains that these installations should not proceed until a fully compliant solution is available.

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