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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


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  • 0

    Sparkingchip:

    My phone line was installed in the 1960’s . . . 


    . . . The earth electrode is still in place, but the BT guy that replaced the line box disconnected the earth conductor . . . 




    There is used to be some surge suppression between the two wires, but nothing to earth. Originally, telephones became so popular, they quickly out-stripped the number of copper pairs back to the exchange. One relatively quick option was to install a “party line” option to the exchange. This meant the speech path was shared, so the other property could “listen in” to a conversation. However, the bells were connected to earth on one side, giving the option to ring the bells at the two properties separately. When one phone was in use, both numbers were marked as busy. Newer electronic exchanges did not have the ability to have a “party line” option, so the earth connection at a property no longer had a use, and was disconnected. 


    Regards,


    Alan. 

Reply
  • 0

    Sparkingchip:

    My phone line was installed in the 1960’s . . . 


    . . . The earth electrode is still in place, but the BT guy that replaced the line box disconnected the earth conductor . . . 




    There is used to be some surge suppression between the two wires, but nothing to earth. Originally, telephones became so popular, they quickly out-stripped the number of copper pairs back to the exchange. One relatively quick option was to install a “party line” option to the exchange. This meant the speech path was shared, so the other property could “listen in” to a conversation. However, the bells were connected to earth on one side, giving the option to ring the bells at the two properties separately. When one phone was in use, both numbers were marked as busy. Newer electronic exchanges did not have the ability to have a “party line” option, so the earth connection at a property no longer had a use, and was disconnected. 


    Regards,


    Alan. 

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