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interpretation of SPD para in GN1 (18th)

psychicwarrior
"It should be noted that SPD's required by Section 443 of BS 7671 are to protect the electrical power installation, but exclude any electronic equipment, the protection of which is outside the scope of BS 7671."


what does that break down to mean ?


- that SPD's are for the (im interpretting 'electrical power installation' here to be...) fixed installation and any thing not permanently connected, is excluded ?

- that SPD's are for the fixed installation and any thing connected (permanently or otherwise) is included, *except* electronic equipment (which is pretty much every thing these days) ?

- that SPD's are for the fixed intallation and any thing connected is included, but what is the last bit re: electronic equipment about ?

- something else ?


Initially I went for the first of the above, but the definition of electrical equipment is clear enough, so what is that para getting at.


Hmmm

Habs
  • 0
    Humm, sounds like a bit of an odd statement - the 18th Ed (both 443 and 534) has many references to type 3 SPDs protecting category I equipment (which I think would normally cover most electronic equipment). I wonder if it's been left behind from an earlier edition of the GN which was aligned with the 17th Ed - which had a much less thorough approach to transients.

      - Andy.
  • 0
    Whilst perhaps not well worded, telecomms and similar systems ('ICT systems') are specifically excluded from the scope of Section 443 of  BS 7671, as it is covered sufficiently well in other standards.


    See the paragraph (it's part of the Reg, not the Note) after Note 4 in 443.1.1, which says 'This section does not cover overvoltages transmitted by Information, Control and Telecommunications (ICT) systems. See BS EN 50174, BS EN 62305-4 and BS EN 61643-22.'


    ICT systems covers more than simply telephone and data though ... it includes security, controls/BMS etc.
  • 0
    Also worth noting, though, that where SPDs are required for the electrical installation, they should also be provided for ICT systems ... at least on the points of entry/exit ... you just can't use 443 for this, you have to use the other standards referred to in 443.1.1.


    Also worth pointing out that surge protection at the premises may not be provided by a wired / FTTC broadband or telephone service provider.
  • 0
    Isn't this similar to BS7671 having nothing to say about things plugged into sockets, yet still requiring those sockets to be RCD protected?
  • 0
    @gkenyon - yes I can see that as a reasonable explanation. The para is not worded well at all in that case in my opinion.
  • 0

    Whilst perhaps not well worded, telecomms and similar systems ('ICT systems') are specifically excluded from the scope of Section 443 of  BS 7671, as it is covered sufficiently well in other standards.



    But surely there are loads of electronics that aren't anything to do with ICT systems - everything from RCBOs to dimmer switches to electronic "transformers" for SELV lighting to variable speed drives for motors.


      - Andy.

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