tns or tncs

[multimick]

strange one, supply comes off a pole down wall into house ,cable looks newish and split conn,however on measuring fault current line to neutral was 1.6 ka and line to earth was 1.15 ka ze 0.19 i would have thought from a pole it would be a tncs but maybe not ?

 

[Leesparkykent]

Well from what you’ve written it suggests it’s TNS....The fact that split concentric cable has been used.

 

[multimick]

yep it does test like tns (tested a few times)

 

[R-fur]

An LV OHL can be TNS or TNC-S. It would be unusual for the DNO to use a split concentric for a TNC-S supply. But the supply could have been recently converted.

 

[multimick]

am i missing something i thought a tncs would be split conn ?

 

[R-fur]

A TNC-S would normally be a straight concentric cable. Split concentric is normal for a TNS supply.

 

[multimick]

thanks rfur ,see the difference now

 

[davesparks]

strange one, supply comes off a pole down wall into house ,cable looks newish and split conn,however on measuring fault current line to neutral was 1.6 ka and line to earth was 1.15 ka ze 0.19 i would have thought from a pole it would be a tncs but maybe not ?

How have you confirmed that it is split concentric?

 

[multimick]

i haven't i just assumed ,sorry

 

[Lister1987]

Purely from a trainee POV; what's the cable difference? Armour arrangement? Example images?

 

[davesparks]

Purely from a trainee POV; what's the cable difference? Armour arrangement? Example images?

Concentric cable is 2 core and has a single inner line conductor with an outer PEN conductor.

Split concentric cable is 3 core with a single inner conductor, part of the outer conductor is a bare copper CPC and the rest is insulated neutral strands.