Discuss Zdb before dead tests. in the Electrical Forum area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

swaley

-
Reaction score
31
Hi guys got my assesment in 3 weeks and want to get my testing spot on. Little confused whether to test Zdb on 2 way CU before dead tests?? Or do I jump straight into continuity? Thanks in advance.
 
Hi guys got my assesment in 3 weeks and want to get my testing spot on. Little confused whether to test Zdb on 2 way CU before dead tests?? Or do I jump straight into continuity? Thanks in advance.
Test procedures as per BS 7671 would be my choice. Would be interesting to know your reasons for wanting to test Zdb prior to dead testing.
 
Test procedures as per BS 7671 would be my choice. Would be interesting to know your reasons for wanting to test Zdb prior to dead testing.

I suppose that would depend on whether the OP is using an existing supply or not. Its not clear. I suspect he means dead testing the circuits on the sub DB
 
Dead tests should always be done first before live tests for safety purposes.

As you are not being inspected on safety, personally I would not worry to much. However if you want to donit by the book then dead tests first.
 
Dead tests should always be done first before live tests for safety purposes.

As you are not being inspected on safety, personally I would not worry to much. However if you want to donit by the book then dead tests first.

Thanks I'm constantly over thinking everything. I will just follow OSG in future.
 
Yes. Why you ask?

That wasn't clear from the op.

So I would install and test the sub main first, including live tests...

Then move on to the dead and live live tests in the new building.

You need the ze + R1 +R2 of the sub main top check the Zs of the sub main (which is also the zbd)

Then you have the zbd +R1 +R2 and then the Zs ....

So one EIC, 2 schedules ....

Where is the RCD?
 
Technically there is no such thing as Zdb the measurement at your two way CU is Zs. Try to use the correct terminology.
 
But widely used
I agree but not a abbreviation I ever quote. I believe it has been adopted where a true value of Ze cannot be established due to operational restrictions and the value is often referred to as Zdb which although often quoted is not a recognised abbreviation.
 
I agree but not a abbreviation I ever quote. I believe it has been adopted where a true value of Ze cannot be established due to operational restrictions and the value is often referred to as Zdb which although often quoted is not a recognised abbreviation.
I have always taken Zdb as the measured EFLI at a DB to avoid confusion between Ze and Zs.

Ze would always Be Ze whether tested with the main earth disconnected or with parallel paths in place.

Although not a recognised abbreviation I've found it can save a lot of confusion. Especially handy when dealing with several DBs in an installation. If there was only one DB then there would only be Ze and Zs.
 
Yes I know that I was just wondering in what context if any it would be used in a technical report/document. My initial comment on it being the OP shouldn't really use a non recognised abbreviation on an assessment.
 

Reply to Zdb before dead tests. in the Electrical Forum area at ElectriciansForums.net

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

Electrical Forum

Welcome to the Electrical Forum at ElectriciansForums.net. The friendliest electrical forum online. General electrical questions and answers can be found in the electrical forum.
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock