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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
    Whether required: that depends on whether damage to electrical items (e.g. LED lamps, POS terminals etc) would interrupt commercial activity.

    Switching: well, in principle an adjacent  building could be generating switching surges, but that doesn't seem to figure into any of the actual rules (compulsory, or risk assessment etc).

    Type 1's are part of the LPS - they equipotentially bond the wiring system to the rest of the LPS so that there's less chance of flashover between say a water pipe and nearby cabling, starting a fire. Thus they are not intended to provide protection for electrical equipment. For that you need a type 2 in addition, or possibly a combined type 1+2.
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  • 0
    Whether required: that depends on whether damage to electrical items (e.g. LED lamps, POS terminals etc) would interrupt commercial activity.

    Switching: well, in principle an adjacent  building could be generating switching surges, but that doesn't seem to figure into any of the actual rules (compulsory, or risk assessment etc).

    Type 1's are part of the LPS - they equipotentially bond the wiring system to the rest of the LPS so that there's less chance of flashover between say a water pipe and nearby cabling, starting a fire. Thus they are not intended to provide protection for electrical equipment. For that you need a type 2 in addition, or possibly a combined type 1+2.
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