Main earth tns

[graham123]

On a domestic tns suppy what do you class as your main earth onto test sheets? As I have a unsheathed 2.5 from sheath to earth block then 16mm to db. Get fine ze readings. Would you record it as 2.5?

 

[Forty4]

Record what comes from the MET to the DB. You don't record the size of the distributor tails going to the meter do you.

 

[Baker1988]

Dont record the distribution earth just the installation earth from the met

 

[davesparks]

But do still do the calculation to establish whether said bit of 2.5 is ok or not.
And I'd hazard a guess that it'll be an imperial size cable rather than metric.

 

[telectrix]

What,s your PEFC?

 

[AndyL]

Record what comes from the MET to the DB. You don't record the size of the distributor tails going to the meter do you.

Have to disagree with this i'm afraid, earthing conductor is from the means of earthing to the MET

 

[telectrix]

debatable point. we should ask niceic who will then come up with a 20 page fact sheet which will say nowt.

 

[shanky887614]

Have to disagree with this i'm afraid, earthing conductor is from the means of earthing to the MET

wrong the MET in domestic is within the ccu so thats what you write down.

the core coming of the pilc doesnt go straight toto board and is not your problem, if the external loop impedance is too high its in the hands of the supplier

 

[AndyL]

Or could look in BS7671, where it has the definition of an earthing conductor

 

[brucelee]

Unless on a rewire someone has correctly supplied a external MET to facilitate easier connection of earthing and bonding as well as being better for I&T

 

[davesparks]

wrong the MET in domestic is within the ccu so thats what you write down.

What on earth would the MET be doing inside a cooker control unit?

The MET can either be the earth bar of the CU or an external earth block, personally I normally fit an earth block.

 

[Andy78]

I'm with the other Andy on this.
The earthing conductor is the conductor between the means of earthing and the MET. If the MET is in the CU then you only have one conductor anyway. If the MET is external to the CU, then the conductor between the CU and MET is really a CPC.