Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Replies 17 replies
  • Subscribers 44 subscribers
  • Views 1241 views
  • Users 0 members are here
Options
You may also be interested in

is a surge protected extension/powerstrip any use without upfront SPDs

psychicwarrior

hello goodly morrow

If a T3 SPD, 'must not' be used, as per 7671,  without upfront (T1+)T2 SPD  (for want of better words) ,  what real value is a plugged in surge protected extension lead/powerstrip  (which is a T3 in effect one presumes) without a T2 somewhere upfront ?

Or is it really just a sacrificial item and really is better to have.

Perhaps the components are pretty useless and cheap in most of the consumer grade surge leads/strips.  May be connected devices (via power blocks and transformers etc) can cope just as well  ;-)

Engineering references and regs are not going to use the anything is better than nothing finger in the air style and have to present a considered, tested and  co-ordinated approach. The consumer market takes a different view it seems and makes little to no effort (does it) to advise that surge protected powerstrips/leads 'must not be used' without upfront SPD,  but if course such is not part of fixed wiring any way so no need, or is there a need . 

  • 0 in reply to psychicwarrior
    psychicwarrior said:
    One brand stocked by CEF states it conforms to BS 5733, BS EN 61643-11   (I don’t have the BS docs but is 61643  about SPD types conformance etc). 

    BS 5733 has nothing to do with SPDs and overvoltage protection  and, for the purposes of this discussion, is not really a valid.

  • 0 in reply to gkenyon

    however, its good to know it meets '5733, as a lot of cheap Chinese extension leads and adaptors etc don't. It sets a minimum standard for the housing strength,  and performance in a fire...the insulation of live part and creepage and clearances between them. But no, nothing  SPD specific.

    That is indeed in  61643, and yes, part  11 is all about SPDs for AC systems.

    Mike.

  • 0 in reply to psychicwarrior

    So it is a T3 

    Although live every standard, the specification sets only a minimum requirement - the manufacturer is free to improve on that if they wish (and may well feel inclined to do so if there was a financial incentive to do so). Make something that has the protective characteristics of a T3 but the survivability characteristics of a T2 (or near to) the standards might only allow you to label it a T3 (rather than say T2+T3) but it could still give satisfactory service without an upstream T2.

    BS 7671 of course has to take the precautionary apporach - many thing labelled T3 wouldn't survive without an upstream T2 so that's what it requires. The plug-in filter manufacturers however are playing in a different ball park

       - Andy. 

  • 0

    My trailing lead SPD has protected my electronic stuff for 20 years, through thunderstorms and lightning. My computers, mobiles, tv, broadband, smart meters. Now the esteemed regulations are banning it? Ok, I'll get an electrician to charge me £1000 for an £80 all bells and whistles new fusebox.from Screwfix. Really? Regards, UKPN

  • 0 in reply to gkenyon

    I dont think the discussion was deviating from SPD by its mention and it was a comment about what was listed in the info, but perhaps you were worried.

    I did look it up though   ;-)

  • 0 in reply to UKPN2025

    Don't worry. Unless you fix your extension lead to the wall, it's not even covered by BS7671. So what's in that standard makes no difference.

  • 0 in reply to AJJewsbury

    The best SPD protection would be offered by cascading a T! SPD into a T2 SPD and then very close to the appliance a T3 SPD.  Sounds simple in a UK domestic dwelling until people understand that a type 1 SPD is mainly used for lighting protect/transients so I suspect it would be very rare to find in the average UK 3 bed semi detached house.  A few years ago I started a thread on this forum about should SPD type 2 be mandatory of UK CU/DB and it was met with mixed response.  Caveat time, should a SPD type 2 be mandatory, in my mind yes BUT and this is the caveat.  Is it a new install or an existing one from yesteryear which may not accomodate an SPD type 2.  This is the same type of conundrum of EICR......Does it need to meet the new regulations or the one it was designed an installed to from several years of decades ago?

    To draw a parallel with the EICR / Should SPD be mandatory conundrum

    Look at fire safety systems.  Sometimes those regulations say that system needs to meet the new regulation and that is final.  Any remedial work needs to meet the new regulation for the WHOLE system.  I am sure there are others on this forum that can explain this better than myself.  

Community Rules & Guidelines