Pyro supply TNS TNCS ??

[shepelec]

Hi everyone, I'm looking for some info on a Pyro supplied C/U. I'm working in a complex that has 16mm pyro fed boards. Are the supplies TNS TNCS etc and when measuring ZE how do you do this as the main earthing is from the gland on the pyro, surely you're not expected to disconnnect it ?:|

thanks in advance

lou

 

[NozSpark]

This is probably fed from a meter cupboard somewhere,, if you can get a look in there otherwise it is being presented to the CU as TNS...

To test your Ze remove the earth bar and chassis links from the CU, you could leave all the final circuit CPCs and bonds connected to it if it's wired in T&E,, if it's metal conduit then you have a bit of a problem

 

[SLIPSHOD & SLAPDASH]

If its fed in MICC then its a sub main and you will be looking at a Zdb, not Ze. On most certs there is a section to fill in only if the board is not connected at the origin. If you do need a Ze its not tested at your mentioned board but at the origin of the supply

 

[Andy™]

if that DB is treated as its own installation, then it could well be Ze...

 

[SLIPSHOD & SLAPDASH]

[quote name='Andy

 

[shepelec]

Thanks for the replies, i have found the distribution cupboard and its labelled PME, the db is a separate installation as it is for a flat so i take it i measure ZE at the db as its the origin of the installation ??

 

[Andy™]

How in this case ?

there was a thread a while back in plenty detail

short version: if the DB is its own installation, then submain is external to it, therefore Ze can be taken.

 

[NozSpark]

Also the Pyro submain may have been "adopted" by the DNO

 

[SLIPSHOD & SLAPDASH]

Thanks for the replies, i have found the distribution cupboard and its labelled PME, the db is a separate installation as it is for a flat so i take it i measure ZE at the db as its the origin of the installation ??

There is a good example of a 'seperate installation'

The origin (in your case) will depend on which end of the cable the meter is.

 

[NozSpark]

Thanks for the replies, i have found the distribution cupboard and its labelled PME, the db is a separate installation as it is for a flat so i take it i measure ZE at the db as its the origin of the installation ??

You won't be able to as you would have to turn off the entire installation and I dare say that the building owners, mainenance company and occupants wouldn't give you authorisation to do that...

This is where "by enquiry" comes in