What kind of supply do I have (TT,TN,etc)

[trey]

The supply comes in encased in lead pipe. This appears to have a L and N. The lead casing goes to Earth block. Then earth bonding and earth from CU connect to this block. The L goes to meter and on to CU, the N goes to meter and then CU but there is also a cable between the N and the Earth block.

So diagramatically (this might not work):
[code:1]
L N E
| | |
***** 3 separate connectors
| |-|
| | |
*** | Meter
| | |
***** CU
| | |
[/code:1]

So I tried working it out from the descriptions on TLC's guide. Is it TN-S or TN-C-S? From the description of TN-S I didn't think the N and E would be linked at the property (as well as obviously at the transformer).

The other possibility is than I have only L and N/E and the link to the sheath (lead pipe) is just earthing rather than a connection all the way back.

In case it help, the house is 1960s ish (former MOD) and in the MEB (East Midlands) area.

 

[JohnD]

a cable between the N and the Earth block.

where is this cable?

can you post a photo?

//www.diynot.com/forums/viewtopic.php?t=129539

 

[trey]

The "block" is on big unit with the fuse. The cable comes in below, the earth block is on the Left, the Live in is in the middle with the fuse inline and the N is to the right. The cables to the CU or meter (for Earth) come out the top. The cable between the N and E is on the top - ie there are two N cables, one to the meter and one the Earth block.

The connection to the lead sheath is wide, thin stranded metal.

Sorry, no picture.

 

[JohnD]

if the cable is in plain view, as you say, it is probably a DIY bodge (this is not permitted).

A TNC-S does have such a connection, but it is provided by the electricity supplier and is not visible. Additionally there would be a durable label near the meter, saying "Protective Multiple Earth"

Yours sounds like a TNS

There are some pictures

here //www.diynot.com/wiki/electrics:earthing_supply_types_and_bonding:earthing_arrangements

 

[trey]

No, I have a label that says "Protective Multiple Earth".

And it's not a bodge - had elec board out recently for main fuse upgrade and they didn't say anything. Also the cable is exactly the same and the cables to the meter (size, colour, appearance).

So it probably is TN-C-S. Just wondered.

 

[JohnD]

shame about the picture

 

[sm1thson]

Hmm, a very unconventional setup, can we have a picture anyway!

 

[GaryMo]

No, I have a label that says "Protective Multiple Earth".

So it probably is TN-C-S. Just wondered.

If there's a PME label then your assumption that it's TN-C-S would be correct.