TT or TNCS

[mst]

I went to see a job today .The installation was what i thought to be TT however the 100ma and 30ma was nowhere to be seen. I guess it was wired early to mid 80s.

The TT electrode termination was a bit loose. What confused me a bit was where the cutout was (bearing in mind it wasnt your normal looking TNCS) cutout. there was a henly block with phase (line) and neutral in it and then a lenth of 16mm from the board going into that block. Im thinking maybe it joins to the neutral so someone was trying to make it TNCS????or TNS???? But i dont think it would have PME avaliable due to overhead wires coming in.

Wish i had my camera

Has anyone seen this before?

 

[Lectrician]

PME can take on many looks, especially on retro installs.

A pic would have helped.

Often, rods get left in on board changes and PME upgrqades, not for any electrical reason really - just lazy.

Overhead services do not automatically mean TT.

Many PME's are overhead. you want to see my rural areas.

Older service drops where terminated with a henley fuse block and a standard henley block adjacent to it for the neutral. The PME earth is obviously taken from this block.

 

[mst]

Ahh many thanks Lecky.

I advised a periodic , but maybe ill just do a ZE test for her tommrow and see what i come back with. hopefully it will be below .35. Never seen PME like it before.
Bit embarssing really

Thanks and happy new year to ya.

 

[RF Lighting]

Take your camera with you.

Thats an order



We love pictures!

 

[mst]

Yes i know you do RF

Ill be suprised if you havent got my holiday pictures in your collection!

 

[JohnD]

and http://i113.photobucket.com/albums/n228/JohnD_UK/NakedWife.jpg

 

[reggie perrin]

I've come across TT systems where an earth has been dogged into the neutral.

Trouble is if there's no PME sticker at the cut-out or on any nearby poles* you have to assume it's TT surely...?






*poles in this context is not of the East European neighbour who's gate-crashed your party and has been sleeping on the settee for the last three months.

 

[ColJack]

the only poles that get to sleep at my house while i still breathe, will be 6 ft under the shed in a plywood box..

 

[ban-all-sheds]

and http://i113.photobucket.com/albums/n228/JohnD_UK/NakedWife.jpg[/QUOTE]
Excellent!!


As for the OP, IMO if it doesn't have a proper label stating it's PME, then it should be regarded with utmost suspicion as a DIY TN-C-S.

Confirm with the DNO. TN-C-S without PME is very dodgy.

 

[reggie perrin]

With a TT spike to keep 'em firmly in place...

 

[securespark]

TN-C-S without PME is very dodgy.

As is PME without MEB's.

 

[mst]

Thanks folks.

Bas as you say, a phone call to western power will be made.
And i agree the TNCS without the PME just dosent mix.

have a good new year to all