Inspect and Test Question

[OtiStu]

Hi all,

Probs a simple one here but when testing a 3 phase board for ze as part of a periodic inspection plus part initial verification of a small db supplied by this board should I note the main 3 phase ze within the supply parameters section of cert and then the small db as zdb within the schedule of tests? Or just use the main ze for both?

Studying for 2391-52 course

Cheers

 

[westward10]

An installation with a single source of supply will only have one Ze everything else is Zs.

 

[IAmSparkytus!]

Most recent NIC test sheets have it so your earth loop test carried out at the origin of supply would be your Ze. Earth loop carried out at the main switch in any fuse boards would be your Zdb

Zs would be your earth loop tests at end of circuits

 

[Lucien Nunes]

Ze is the external loop impedance, so by definition it does not incorporate any part of the installation and can only apply at the origin.

 

[Chivers]

Worth noting if you were completing an EICR on both these boards there would be a separate test sheet for each board and each sheet would have the supply characteristics at the top for you to fill in. so if you view it like that it will become more obvious. hope that helps.