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Hi Guys,
Had a strange issue i have never come across on a domestic job before and made testing a nightmare.
Was a couple of new circuits in a bathroom, new CU and earthing upgrade gas/water, new blah, blah, blah.
Did some quick continuity and IR checks prior to the CU change all came out ok so ripped the old out and in with the new one.
Went to do final testing and meter will not earth loop Ze or any Zs readings. Meter comes up with error 5 every time and will not test, now up till now whenever this happens it usually means neutral missing so head scratching started, checked meter instruction book (felt a bit of a girl at this point, no real man reads instructions) and error 5 in noisy earth, thought this a bit strange as this was a council estate and no where near industrial areas so checked with Fluke uk and they confirmed this. told me how to get round the noisy earth problem when testing so sorted.
Still cannot understand how these houses can suffer such a problem. any ideas ?
 
Have you ruled the meter being itself faulty by getting a successful Ze/Zs reading elsewhere? (as in not the place you are currently working).
 
Have you ruled the meter being itself faulty by getting a successful Ze/Zs reading elsewhere? (as in not the place you are currently working).
See what your saying, and TBH did not even think of the meter being an issue.

Should have given the supply also really. Its a TN-S supply cable installed about 1954 so the owners said, quite an old service head, old yellow box jobbie, still good condition for its age though.
 
you could of caalculated it with max values of ze...... but suppose just another why is this happening..
How can you calculate Zs and Ze just from an assumption on supply, not very proffessional.
In saying that, I now know how to use meter in this situation.
Which brings another question, do other meters suffer this problem or are most people unaware of this at an installation.


Is this something to just ignore or inform DNO. ?
 
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well you could of used max ze value and just take your reading on R1+R2 and add together..... but i see you point a strange one..
 
How can you calculate Zs and Ze just from an assumption on supply, not very proffessional.
In saying that, I now know how to use meter in this situation.
Which brings another question, do other meters suffer this problem or are most people unaware of this at an installation.

Is this something to just ignore or inform DNO. ?

The only MFTs that are fairly immune to high noise are the Meggers due to the averaged multiple measurement technique employed. Megger users rarely see a high noise warning, I see an average of one a year, all of those have been in known high noise industrial areas.

If you inform the DNO I doubt they will take action, they will probably just pass the buck, saying it's your clients responsibility. You will be lucky if you can get them to formally test or monitor the supply let alone the local network, but we live in hope.
 
This phenomenon, relates back to other threads here on the forum on the need for ''Clean Earths''!!

This is a perfect example of why a real clean earth system is often employed where noisy/dirty earthing is known to exist. Also why you tend to find the bigger IT processing facilities are located away from heavy industrial areas/parks and the like...
 
seen the noise symbol once on megger 1553 although it still returned readings, pylon stood exactly at bottom of garden which i put it down to
 
Also why you tend to find the bigger IT processing facilities are located away from heavy industrial areas/parks and the like...

This is why i was suprized to have it where this was. It was a large council estate nowhere near any ind/com sites.
Perhaps jabbajaws is right about the meter being the culprit but was not aware they could.


Oh Murdock, that was a joke reply BTW :)
 
It could well depend on the way the DNO local distribution network has been arranged. These day's every home is kicking out noise from all the modern electronic stuff we all now take for granted. Everything now, seems to be controlled one way or another by electronic this and that's, and many will have mains filtering that's connected to earth. Not saying this is the cause in your particular case, but it's certainly going to become a problem in the future, along with the amount of harmonics, that's also associated with today's modern living... lol!!
 

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