Stupid question comming up...

[Superspark23]

I should know this been in the trade for 3 years now, just recently completed my nvq and done the 2382 and 2392

But what is a Zdb? never heard of this before and just read it on 2 different threads.

 

[trev]

EFLI at a submain

 

[Superspark23]

Ok then cheers just so i know im correct

Ze is with the main earth disconnected at the consumer unit

Zbd is taken with the main earth still connected at the consumer unit

and Zs is at the end of the circuit

Cheers

 

[trev]

Incorrect
Ze you're right there
Zdb is at a submain eg you have a three phase supply, from that you have supplied a single phase CU
Zs you're right

 

[Engineer54]

Zbd is the Zs at a sub-main panel, normally where there are several sub-main panels. It just distinguishes between Zs of the panels final circuits from the incoming supply Zs...

Zdb the db stands for distribution board, and will normally have a the DB number attached to Zdb (as is Zdb.xxxx )

 

[tuckermot]

agree with above

ze at origin
zdb at 2nd ccu supplied via main ccu

 

[telectrix]

it's a simples thing to remember. Ze at origin = eeeeesy' Zdb at sub main = zebedee, time for bed. Zs is end of circuit, Zssssssssss time for sleep.

 

[ian.settle1]

As said Zdb is used for the Ze for a distribution board but I think you will find that it is a term that does not have a official standing in the regs.

 

[Superspark23]

I got that nice one. Learn something new every day.

 

[Engineer54]

There is no such thing as taking a Ze at a sub-main board/panel, as there will ''Always'' be parallel earth paths, so it is a Zs value you will be recording, not a Ze value!! This is how the term Zdb came about, to differentiate between main and sub-main ELI tests....

 

[morph]

There is no such thing as taking a Ze at a sub-main board/panel, as there will ''Always'' be parallel earth paths, so it is a Zs value you will be recording, not a Ze value!! This is how the term Zdb came about, to differentiate between main and sub-main ELI tests....

exactly how can ZE be anywhere except at the origin..

 

[GLENNSPARK]

A garage dis board being a good example here.......house dis board=Ze....
house final circuits=Zs....garage dis board=Zdb and garage final circuits=Zs for that part of the installation (garage)......as has been said already....just a way of identifying whats what......