Niceic Contractor Green Eic.

[Lee Sparks]

Hey guys,

Quike query.

I helped on a EIC testing & inspect the other day.

When we filled out the green contractor niceic EIC, i noticed that there are two boxes to state the Ze of the installation.

I wondered why there is two boxes?

One box for Ze in "supply characteristics" and the other in the "Particulars of installation at the origin".

I have not noticed this on other certs.

The electrician that was filling out the cert was testing the whole house as he changed the fuseboard and needed to do the cert and asked if i would like to attend. I jumped at it.

He filled out the two boxes in the end, the 1st box he stated the Ze measured at the main intake position then the 2nd box was stated the Ze measured from the main switch at CSU and earthing conductor.( the way im familiar with)

Hope someone can clear this up, cause it threw me.

Lee.

 

[SPECIAL LOCATION]

Isn't one in the Supply characteristics and the other in the particulars of the installtion....

And where the first could be by enquiry..

as on some sites it is not feasible to turn everything off and disconnect the earthing arrangements to measure Ze...

whereas a sub main to a distribution board feeding part of a site may well be able to have the Ze for that board (AKA Zdb) measured.

Within a domestic it is not normally too hard to isolate the whole installation to read Ze.

Ask to have another look at your mates forms...

The small print actually says something like....

External Earth Loop (by enquiry)

& the other says Measured Ze

:coffee

 

[SLIPSHOD & SLAPDASH]

With out the forms to hand i am sure one box is for the supply charateristics and the other is only if the dist board is remote from this. So the second not needed in a normal domestic situation where the C/U is adjacent to the head

 

[Lee Sparks]

Thanks lads,

It makes sense now.

 

[Ash]

how can you have two Ze results?

A DB remote would be Zs

 

[Zeespark]

Ash Zs = Ze + R1 + R2, you are thing remote, which is unofficially Zdb.

Andy Guinness

 

[Sidewinder]

AKA colloquially known as Zdb

 

[Sidewinder]

Zee beat me to it

 

[brianabsolute]

Explanation given to me by NICEIC as follows:

"Supply Characteristics Ze" = DNO maximum (i.e. 0.35 for TNCS, 0.8 for TNS) ;

"Particulars of installation at origin Ze" = your measured Ze.

 

[steptoe]

Explanation given to me by NICEIC as follows:

"Supply Characteristics Ze" = DNO maximum (i.e. 0.35 for TNCS, 0.8 for TNS) ;

"Particulars of installation at origin Ze" = your measured Ze.

err,

the only flaw you have here is they are NOT DNO max figures,

they are the max figures allowed for in the calcs for 7671 etc,

 

[Steve3948]

DNO are a law of their own, recently had supplies where above 0.25 was not acceptable and they insisted onTT.

 

[Lee Sparks]

Explanation given to me by NICEIC as follows:

"Supply Characteristics Ze" = DNO maximum (i.e. 0.35 for TNCS, 0.8 for TNS) ;

"Particulars of installation at origin Ze" = your measured Ze.

Thanks mate, sums it up perfect.

 

[brianabsolute]

Rodney - good point, so in my original post, for DNO read BS7671. To-date this kept the NICEIC assessors happy - although they have been known to change their minds!