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my surge protection 'cpd', such as it is...

psychicwarrior
Good morning all


I have obtained the following [I feel as the] 'best we can do for now' information from the DNO. They were helpful in my test case request for info.


"...address 1:

LV underground - 362m

HV underground to primary-  2000m

No Surge protection devices


address 2:

LV underground to substation - 110 m

HV UG from substation to HV pole is 823m then 301m 11kV overhead then 190m HV UG to the primary substation.

Distance to cable termination with surge protection device from secondary substation is 1124m (823m 11kV UG + 301m 11kV Overhead).  The nearest cable

termination does not have surge protection installed. ..."


In relation to the risk assessment equation variables dealing with distribution cable lengths  ie. the Lpal Lpcl Lpah Lpch, how would one fit the given values into the variables ?


For addr1, ignore the HV (e.g. use zero for Lpah Lpch),  then take Lpcl as 362 and Lpal as 638 ?


For addr2, i'm not sure on this one ?


Thanks for your input.

Habs


Parents
  • 0

    psychicwarrior:


    Interesting re: the phone line concerns - perhaps all one can do, given it belongs to the phone company up to the master socket and is not BS7671, is advise the client that it too needs looking at and to contact the supplier to have it assessed - or can someone fit something themselves without messing with the master socket - will have to have a read. Then there is fibre (dependng on construction materials) to consider...Or is it really immune as one might think.


    Thank you all again.




    The requirement in BS 50174-3 (referred to from BS 6701 and BS 7671) is to fit SPDs "at all building entrances if the IT cable contains metallic cable elements, and where inadequate protective measures have been provided in the external IT network".


    There are telecomms-specific devices available to do this.


    These days, it's important to ensure you purchase SPDs that can cope with the VDSL2 bandwidth.



    Zoomup:

    The official advice ........

    http://phonefault.com/lightning-damage/


    Z.




    There's a statement on this linked site, that says " There is lightning protection fitted inside each Master Socket – even if it’s the old style."


    There is almost certainly surge protection at the Exchange and the FTTC cabinet.


    However:


    (a) I'm not sure it's always the case that surge protection is installed in all NTE5 Master Sockets. I understand that when we moved from ADSL to VDSL, SPDs were removed as they were affecting data rate. (Whilst info on this is sketchy, it's verified by vendors of the sockets, e.g. this listing on a popular internet sales web-site clearly says "Latest Design. Does NOT Contain Voltage Surge Protector as this can reduce BroadBand speeds.")


    (b) Even if there is, or you have the older style master socket with the SPD in it, there's definitely no surge protection to Earth at your installation (i.e. your MET), only between the two conductors. (And as the web-page says, protection of your stuff after the master socket is your problem).


    FTTP is a different story of course - fibre doesn't import overvoltages.




    So, the question as to whether SPDs affect broadband speeds when using VDSL?


    Well, I'm not 100 % sure. Quite possibly, the original inexpensive types did affect data rate.

    There are certainly devices that operate OK for CAT5 and CAT6 networks, and there are various options available for broadband lines (but probably outside the cost of the NTE5 master sockets).


     

Reply
  • 0

    psychicwarrior:


    Interesting re: the phone line concerns - perhaps all one can do, given it belongs to the phone company up to the master socket and is not BS7671, is advise the client that it too needs looking at and to contact the supplier to have it assessed - or can someone fit something themselves without messing with the master socket - will have to have a read. Then there is fibre (dependng on construction materials) to consider...Or is it really immune as one might think.


    Thank you all again.




    The requirement in BS 50174-3 (referred to from BS 6701 and BS 7671) is to fit SPDs "at all building entrances if the IT cable contains metallic cable elements, and where inadequate protective measures have been provided in the external IT network".


    There are telecomms-specific devices available to do this.


    These days, it's important to ensure you purchase SPDs that can cope with the VDSL2 bandwidth.



    Zoomup:

    The official advice ........

    http://phonefault.com/lightning-damage/


    Z.




    There's a statement on this linked site, that says " There is lightning protection fitted inside each Master Socket – even if it’s the old style."


    There is almost certainly surge protection at the Exchange and the FTTC cabinet.


    However:


    (a) I'm not sure it's always the case that surge protection is installed in all NTE5 Master Sockets. I understand that when we moved from ADSL to VDSL, SPDs were removed as they were affecting data rate. (Whilst info on this is sketchy, it's verified by vendors of the sockets, e.g. this listing on a popular internet sales web-site clearly says "Latest Design. Does NOT Contain Voltage Surge Protector as this can reduce BroadBand speeds.")


    (b) Even if there is, or you have the older style master socket with the SPD in it, there's definitely no surge protection to Earth at your installation (i.e. your MET), only between the two conductors. (And as the web-page says, protection of your stuff after the master socket is your problem).


    FTTP is a different story of course - fibre doesn't import overvoltages.




    So, the question as to whether SPDs affect broadband speeds when using VDSL?


    Well, I'm not 100 % sure. Quite possibly, the original inexpensive types did affect data rate.

    There are certainly devices that operate OK for CAT5 and CAT6 networks, and there are various options available for broadband lines (but probably outside the cost of the NTE5 master sockets).


     

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