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Sprinkler System Pipework Main Protective Bonding

JE 1872

Good Evening

New to the forum and was hoping some of the knowledgeable people on here could assist with a query on main protective bonding of sprinkler system pipework.

We look after a number of schools as part of various FM contracts and have had fixed wire electrical testing & inspection undertaken at the sites when required over the last 10-15 years. On a few of the EICR's we have received recently it has been highlighted that their is no main protective bonding to sprinkler system pipework, in the sprinkler pump house or where it enters the main plant room within the main school buildings.

This has never been picked up before and as it seems to be the case that their is none present at sprinkler pipework within any of the schools, I was wondering if their could possibly be a reasonable explanation that at design stage, it was deemed there was no requirement for this pipework to be bonded.

Thanks in Advance

  • 0 in reply to Philip Oakley
    Philip Oakley said:
    For those that are doing EICR and other inspections, aren't we getting into the "Rigidly defined areas of doubt and uncertainty" HHGTTG problem that needs a DMZ between the codes?

    Well, I am one of those who is doing periodic inspections but I have absolutely no idea what that means but it certainly sounds clever!

    Philip Oakley said:
    Or at least a clearer mechanism for recording, at the equipment, which side of the fence it stands (or is designed to stand) to provide a level of hysteresis that avoids flip-flopping between codes and inspectors?

    I think the Best Practice Guide 4 was an attempt to do that, at least for the domestic side of things. NICEIC and NAPIT often don't see eye to eye over the most simple issues. The Wiring Regulations Advisory Group had to arbitrate over the debacle relating to single insulated tails in domestic meter boxes. But the subjectivity involved in reporting issues is what makes it all so interesting!

    Back to the OP; would it not be reasonable to ask the inspector how he arrived at a code 2? To do so he would have had to make the determination that the sprinkler pipe was indeed an extraneous conductive part. How did he do that? What danger is he envisaging? Is it shock? What if earthed pumps were in the pipework, would that not mitigate shock? If that were the case, perhaps he was thinking of thermal damage to the cpc's? Or was he just thinking; there is a metal pipe that isn't bonded better just code 2 it to cover my ass. What if careful assessment showed it not to be an extraneous conductive part, would slavishly bonding it make the inspectors code 2 disappear but introduce a real code 2 issue?

    I have always argued that inspectors should set out their concern, If it is a code 2, explain how they perceive it to be a potential danger. 

  • 0 in reply to lyledunn
    lyledunn said:
    there is a metal pipe that isn't bonded better just code 2 it to cover my ass

    Spot on!

  • 0 in reply to lyledunn

    Sorry for the hidden references and Un-Named Abbreviations (UNA).

    HHGTTG : Hitch Hikers Guide To The Galaxy; where two philosophers argue about the consequence of asking AI "The meaning of life the universe and everything" (including EICR code choices?) 

    DMZ: De Militarised Zone, very similar to Hysteresis, where the limits are different depending on which way you are going.

    Overall, highlighting the trickiness between expectations, guidance and rules between the differing participants (and who 'takes responsibility' for which aspect).  

  • 0 in reply to DavidT
    DavidT said:
    (often considered to be 22 kΩ for being "non-extraneous" in the context of touch voltages)

    Although this is not universally agreed upon by experts.

    This is important, as BS 7671 was changed a couple of editions back, and the wording changed to 'dangerous potential' ... it therefore also depends on what 'danger' you need to prevent, and in some cases a value exceeding 100 kΩ is more appropriate.

    Regards the other points you make, and in the general case, yes I agree ... my previous post, as I said, was based on what I could see in the pictures provided (and I summarised that, so the OP could check my observations were indeed correct) ...

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