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Proposal for Amendment to BS 7671 Regulation 134.1.1

Sergio Fernandez

Regulation to be Amended

134.1.1 (Good workmanship and manufacturer's instructions)
Proposed New Wording

    Good workmanship by one or more skilled or instructed persons and proper materials shall be used in the erection of the electrical installation. The installation of electrical equipment shall take account of relevant manufacturers' instructions as long as they are no less safe than the intent of BS 7671.


Statement of Problem/Reason for Change

    Ambiguity of "Take Account of": The current wording is often interpreted as an absolute requirement to follow Manufacturer’s Instructions (MI), even when those instructions are generic, poorly translated, or based on non-UK earthing arrangements (e.g., ignoring PME risks).

    Safety Hierarchy: Currently, installers face a conflict when an MI contradicts a fundamental safety principle of BS 7671. This proposed wording clarifies that BS 7671 remains the primary safety framework for UK installations.

    Accountability of the Skilled Person: It empowers the "Skilled Person" to exercise professional judgment. If an MI suggests a method that provides a lower level of safety (e.g., regarding RCD selection or earthing), the installer is explicitly authorized to prioritize the higher standard.

Supporting Examples for the "Safety Case"

    EVSE Installations: Where MIs might suggest a lack of RCD protection that contradicts Section 722.

    Terminations: Where MIs for domestic accessories may not account for the thermal effects of high-load continuous use (e.g., EV or Heat Pump circuits).

    Foreign Equipment: Industrial machinery with MIs written for IT or TT systems being installed on a UK TN-C-S system.

As always please be polite and respectful in this purely academic debate.





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  • Sergio Fernandez said:
    as long as they are no less safe than the intent of BS 7671

    That bit could be problematic, from the perspective that you would need to interpret BS 7671 to determine what it's intent is.

    BS 0 advises that only a court of law can provide a definitive interpretation of a standard (meaning anything else is merely an opinion).

    Hence, the form of words similar to the following is used in a number of Regulations in BS 7671: 
    "at least the same degree of safety as that afforded by compliance with the Regulations"

    AJJewsbury said:
    While I share you perception that a lot of MI don't make a lot of sense, I'm not sure about applying installation standards (e.g. BS 7671) flatly to the detail of individual items of equipment

    I think this is true. Products to appropriate standards may themselves be less safe (in a particular aspect) than conformity to BS 7671, although I would point out that surely equipment ought to be selected for conformity in general.

    Chris Pearson said:
    I feel sure that it says, "take account of" rather than, "follow" because of potential conflicts between BS 7671 and manufacturers' instructions.

    I think this is a very good point.

Reply
  • Sergio Fernandez said:
    as long as they are no less safe than the intent of BS 7671

    That bit could be problematic, from the perspective that you would need to interpret BS 7671 to determine what it's intent is.

    BS 0 advises that only a court of law can provide a definitive interpretation of a standard (meaning anything else is merely an opinion).

    Hence, the form of words similar to the following is used in a number of Regulations in BS 7671: 
    "at least the same degree of safety as that afforded by compliance with the Regulations"

    AJJewsbury said:
    While I share you perception that a lot of MI don't make a lot of sense, I'm not sure about applying installation standards (e.g. BS 7671) flatly to the detail of individual items of equipment

    I think this is true. Products to appropriate standards may themselves be less safe (in a particular aspect) than conformity to BS 7671, although I would point out that surely equipment ought to be selected for conformity in general.

    Chris Pearson said:
    I feel sure that it says, "take account of" rather than, "follow" because of potential conflicts between BS 7671 and manufacturers' instructions.

    I think this is a very good point.

Children
  • in reply to gkenyon
    gkenyon said:
    I think this is true. Products to appropriate standards may themselves be less safe (in a particular aspect) than conformity to BS 7671, although I would point out that surely equipment ought to be selected for conformity in general.

    As an example 

    If you walk into a Screwfix (other retailers/wholesalers are available) today, you might see "Type AC" RCD/RCBO still on the shelf in some clearance kits. While the product is "safe" in a lab, installing it on a circuit with modern electronics (DC leakage) is less safe than the intent of Amendment 2, which has effectively deprecated Type AC for most modern applications

    Second example

    13A Plug-in Shower Pumps / Waste Pumps

        The Product: Saniflo units or shower booster pumps sold with a pre-fitted 13A molded plug.  (other brands are available)

        The Conflict: The MI often says "Simply plug into a standard 13A socket."

        The "Less Safe" Gap: If that pump is installed in a bathroom (a "Special Location" under Section 7), BS 7671 generally prohibits 13A sockets within 3m of the boundary of Zone 1. An installer following the MI who plugs the unit into a socket just outside the curtain is technically following the manufacturer, but they are significantly decreasing safety compared to the BS 7671 intent of keeping current-using equipment hard-wired and protected by a 30mA RCD in those zones

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