Supply characteristics

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Here is a question regarding the supply to a normal household.
The CU is wired in TN-S (as the earth is separated from the neutral bar), but back at the Elec Boards transformer - would I be correct in saying that the Neutral is connected to Earth (therefore TN-C-S)?
With that in mind, when the Installation Cert is signed up, do you enter supply characteristics as TN-S (as found at the house CU) or do you enter TN-C-S (as this is technically the supply from the E board) ?
 
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Seeing as most sparks don't have access to the other end of the cable, you can only record what shows at the consumer's end of the cable.
 
foofighter said:
Here is a question regarding the supply to a normal household.
The CU is wired in TN-S (as the earth is separated from the neutral bar), but back at the Elec Boards transformer - would I be correct in saying that the Neutral is connected to Earth (therefore TN-C-S)?
With that in mind, when the Installation Cert is signed up, do you enter supply characteristics as TN-S (as found at the house CU) or do you enter TN-C-S (as this is technically the supply from the E board) ?
Or maybe TT, as back at the transformer, not only are N & E linked, they are also connected to an earth rod... ;)
 
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Earthing arrangements such as TT, TN-S, TN-C-S etc are not derived from what happens at the tranny end of the supply.

It all depends on the service head.

A seperate earth from the tranny to head, weather a seperate cable, an extra core in a cable, a cable sheath etc will be TN-S

If the earth is derived from the neutral AT THE HEAD, it will be TN-C-S

In our area, we have split concentric cables at the head - seperate N and E. Therefore TN-S. HOWEVER, these cables go out to the street and joint in feeder pillars - these are basically unfused joint boxes. These pillars are fed with a 3 core 185mm waveform concentric cable, therefore being TN-C-S. The recorded earthing type is still TN-S according to the DNO and NIC.
 

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