CK Tools :) The professionals choice when it comes to Electrical Tools
This official sponsor may provide discounts for members

Discuss Zdb testing on busbars in the Electrical Forum area at

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

Hello All,

New assembly line going in at factory I work at. All single phase assembly stations with lights and sockets or screens and tooling etc.

All our existing lines are supplied via local distribution boards but this new line is having a Zucchini 3 phase overhead busbar installed.

When we installed and tested our current stations, I took a Zdb reading at the distribution board but the busbar system has got me thinking.......would I still need to take a Zdb reading (of sorts) at the busbar tap off box?

If so, this poses me another problem, once the cover is removed, all power is lost from the tap off box (as you would expect) so I am not entirely sure how I would take the reading? Only way I can think of is to keep a tap off box purely for testing with a socket connected to it on a short length of cable which I could them use for taking the Zdb.

Thanks for any advice.




Zdb at the distribution board.

Then do your Zs test at the item connected to the bus bar.
  • Thread Starter Thread Starter
  • #3
Thanks for your reply Rob, that makes complete sense.

I will have to ask the lads installing the busbar for the Zdb reading, it is being connected to an ancient MiniForm board which our landlord refuses to let us anywhere!

No problem with the Zs at the other end.

Thanks again for your help.


You must be able to Zs at the busbar connection point and I would have thought any further impedance increase along the section would be negligible.
  • Thread Starter Thread Starter
  • #5
The only way I can think of taking a Zs reading at the busbar connection point is using the socket on a short cable is mentioned in my original post.

The fuse connections etc within the tap off box are isolated as soon as the cover is opened. I can of course, take Zs at the end of the assembly station circuit and I do this at present when connecting to the distribution boards.


Bulk Workwear - Clothing Suppliers for the Whole Forum Network
This official sponsor may provide discounts for members

Reply to Zdb testing on busbars in the Electrical Forum area at

Top Bottom