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I have a ccu with a Ze of 0.09 and it's supplying another ccu which that board supplies multiple other CCUs I was wondering how I would work out my zs and ze on the other boards?
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I have a ccu with a Ze of 0.09 and it's supplying another ccu which that board supplies multiple other CCUs I was wondering how I would work out my zs and ze on the other boards?
Does it not become Zs at DB? from board to board, I hear what you're saying, but does my statement not hold water in this case?Ze is only at the origin, the rest are Zs.
Measure/calculate the R1+R2 for each distribution circuit and add the Ze. (Zs=Ze+(R1+R2))
Does it not become Zs at DB? from board to board, I hear what you're saying, but does my statement not hold water in this case?
Each board would have its own Zs, sometimes referred to a Zdb. I think we're saying the same thing.Does it not become Zs at DB? from board to board, I hear what you're saying, but does my statement not hold water in this case?
Yes exactly nice one MateEach board would have its own Zs, sometimes referred to a Zdb. I think we're saying the same thing.
But, 'Zs at DB1, 2, 3', whatever, is a statement...nothing wrong with the terminology, whatsoever.Yes it does become the Zs at the DB, but obviously that is also the Zs of the distribution circuit because they are one and the same thing.
Strictly speaking 'Zs at DB' or 'Zdb' are not correct terminology, much like 'ring main' instead of 'ring final circuit', everyone knows what is meant by it, it's commonly used, but it's not correct terminology.
If it's the origin CUU does anything need to go into
"Zs at DB" on the "Schedule of test results" form ?
Nope, unless it's not connected to origin.If it's the origin CUU does anything need to go into
"Zs at DB" on the "Schedule of test results" form ?
I agree with ipf, but there will always be a Jobsworth that disagrees with this though.But, 'Zs at DB1, 2, 3', whatever, is a statement...nothing wrong with the terminology, whatsoever.
Yes, the Zs at the DB goes in the "Zs at DB" box, the clue is in the name, it's not a trick question.
Bit of Confusion there, Someone did tell me I have to do the Ze test with all Parallel paths even at origin seems a bit pointless.Nope, unless it's not connected to origin.
You do your PEFC with all parallel paths connected at the origin not a ZE test .The Ze test determines the resistance of the earthing conductor external to the installation and confirms an earth connection to the installation hence it’s done with no parallel paths connected.Bit of Confusion there, Someone did tell me I have to do the Ze test with all Parallel paths even at origin seems a bit pointless.
If it's the origin CUU does anything need to go into
"Zs at DB" on the "Schedule of test results" form ?
I'm talking about Schedule of test result - Zs at DBYou do your PEFC with all parallel paths connected at the origin not a ZE test .The Ze test determines the resistance of the earthing conductor external to the installation and confirms an earth connection to the installation hence it’s done with no parallel paths connected.
Bit of Confusion there, Someone did tell me I have to do the Ze test with all Parallel paths even at origin seems a bit pointlessI'm talking about Schedule of test result - Zs at DB
The test carried out at the origin DB is the Ze not Zs. This is done with parallel paths removed to confirm the continuity and loop impedance of the DNO supply.ill just take it you don't have to do Zs at DB at origin DB, unless anyone says differently.
Bit of Confusion there, Someone did tell me I have to do the Ze test with all Parallel paths even at origin seems a bit pointless.
That was my understanding.No, Ze is measured with the earthing conductor disconnected to eliminate parallel paths.
Zs is measured with everything connected
Take Ze at the switch fuseWould it be the case that Ze may not always be at the first dB, for example if tails have been extended via fused switch and swa? you'd take ze at the switch, disconnecting earthing conductor, then your 'sub main zs would also be your zs at db1?
As others have said Ze is only measured at intake.I have a ccu with a Ze of 0.09 and it's supplying another ccu which that board supplies multiple other CCUs I was wondering how I would work out my zs and ze on the other boards?
If the Earth is connected to the MET reliably then you get current flowing but the increase in local potential should be negligible in the test.Zs via measurement is a live test, so if I'm testing a plug socket Zs - so once the Live current reaches the MET all Earthed and Bonded metal work will become live - seems a bit dangerous - what is the current and voltage the meter uses for the test?
Would it be the case that Ze may not always be at the first dB, for example if tails have been extended via fused switch and swa? you'd take ze at the switch, disconnecting earthing conductor, then your 'sub main zs would also be your zs at db1?
Ze is not at any DB, Ze is the earth fault loop impedance of the incoming supply.
The e stands for external, it is is the impedance external to the installation.
Ze is the earth fault loop impedance at the incoming supply terminals,
If the supplier has provided an isolator then it is measured between the outgoing L terminal of the isolator and the disconnected earthing conductor, if there is no isolator then strictly speaking it is from the outgoing L terminal of the meter. As meters are sealed we normally measure at the closest L terminal to the meter that is available
It's a live test...….no operation until the voltage is available....indicated by the instrument prior to test.Thanks, Still interested in what voltage Loop Impedance testers use?
Thanks, Still interested in what voltage Loop Impedance testers use?
You could say you shouldn't be touching this and that but you know Zs tests take place without any preparation and probably R1+R2 is calculated from Zs tests etc.
There is no danger,If the meter detects that the voltage rise is above the meters setting, typically 50v to earth then your meter will abort the tests, so the danger is removed.Ok thanks, surprised if it actually uses 230v for the test and doesn't use a transformer.
but maybe people should think a bit more before just plugging there tester into a socket and letting whatever A.C voltage 15mA flow through the earth etc.
Even a low voltage it might not be a "Danger"There is no danger,If the meter detects that the voltage rise is above the meters setting, typically 50v to earth then your meter will abort the tests, so the danger is removed.
The meter will not let you carry out the test if the voltage to earth rises above 50v by a break in the continuity of a cpc connecting to any exposed conductive partsEven a low voltage it might not be a "Danger"
but a child touching a metal faceplate in a residential property while a break in the CPC during such test it's obviously not very good.
Ok thanks, surprised if it actually uses 230v for the test and doesn't use a transformer.
but maybe people should think a bit more before just plugging there tester into a socket and letting whatever A.C voltage 15mA flow through the earth etc.
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