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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.

  • 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.

  • 0 in reply to Dom
    Dom said:
    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.

    BS 7671 won't let you just bond two separate earthing systems together, see Regulation 542.1.3.3. In considering the fault currents that might flow, as indicated in my previous post, the fault currents can be from the HV supply system to either supply ... outside the scope of BS 7671.

    Dom said:
    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.

    But the DNOs operate the HV systems to which the LV systems are connected. It could well be the case that there is no magic wand here.

    Dom said:
    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.

    The problem is that the departure undermines a basic premise of BS 7671, and also introduces risks that BS 7671 (and OPDDs) are not designed to handle. I'm not sure, therefore, it's a logical step to say 'no less safe' as required by Regulation 120.3.

    Dom said:
    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.

    Any organisation is entitled to their opinion, and of course, I'm only providing an opinion here based on the facts as I see them.

    BS 7671 is agreed by industry consensus and public comment. It is in turn based on international standards HD 60364 series, and IEC 60364 series, both developed by agreement between international experts, and which have the exact same requirement as Regulation 411.3.1.1 in BS 7671. 

    So hopefully you can understand why I am unable to say that it's OK to use another approach which does not (at present) have consensus, and in fact undermines the consensus provisions "because it's inconvenient for what we want to do now". 

    Dom said:
    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.

    The Simultaneous Contact issue is not new. OZEV publish information on it themselves. It's been a key part of the risk assessment in the IET Code of Practice for EV Charging Equipment Installation since the very first Edition in 2012. The IET CoP is also developed by industry consensus and subject to public comment.

    The particular provision in Regulation 411.3.1.1 of BS 7671 is not new. 

    Dom said:
    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.

    Please see above. I'm not saying that the risks can't be managed somehow, but there needs to be a consensus-based approach agreed in the correct industry forums.

    In terms of 'position', we can only go off what's published in BS 7671 and the IET Code of Practice for Electric Vehicle Charging Equipment Installation at the present time. It is my opinion that this is the only reliable conclusion to draw.

    In terms of an actual 'determination', only a court of law can provide an interpretation of standards for a given set of circumstances, as advised by BS 0.

Reply
  • 0 in reply to Dom
    Dom said:
    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.

    BS 7671 won't let you just bond two separate earthing systems together, see Regulation 542.1.3.3. In considering the fault currents that might flow, as indicated in my previous post, the fault currents can be from the HV supply system to either supply ... outside the scope of BS 7671.

    Dom said:
    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.

    But the DNOs operate the HV systems to which the LV systems are connected. It could well be the case that there is no magic wand here.

    Dom said:
    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.

    The problem is that the departure undermines a basic premise of BS 7671, and also introduces risks that BS 7671 (and OPDDs) are not designed to handle. I'm not sure, therefore, it's a logical step to say 'no less safe' as required by Regulation 120.3.

    Dom said:
    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.

    Any organisation is entitled to their opinion, and of course, I'm only providing an opinion here based on the facts as I see them.

    BS 7671 is agreed by industry consensus and public comment. It is in turn based on international standards HD 60364 series, and IEC 60364 series, both developed by agreement between international experts, and which have the exact same requirement as Regulation 411.3.1.1 in BS 7671. 

    So hopefully you can understand why I am unable to say that it's OK to use another approach which does not (at present) have consensus, and in fact undermines the consensus provisions "because it's inconvenient for what we want to do now". 

    Dom said:
    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.

    The Simultaneous Contact issue is not new. OZEV publish information on it themselves. It's been a key part of the risk assessment in the IET Code of Practice for EV Charging Equipment Installation since the very first Edition in 2012. The IET CoP is also developed by industry consensus and subject to public comment.

    The particular provision in Regulation 411.3.1.1 of BS 7671 is not new. 

    Dom said:
    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.

    Please see above. I'm not saying that the risks can't be managed somehow, but there needs to be a consensus-based approach agreed in the correct industry forums.

    In terms of 'position', we can only go off what's published in BS 7671 and the IET Code of Practice for Electric Vehicle Charging Equipment Installation at the present time. It is my opinion that this is the only reliable conclusion to draw.

    In terms of an actual 'determination', only a court of law can provide an interpretation of standards for a given set of circumstances, as advised by BS 0.

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