Ze readings change

[amptest]

Hi all have a problem with zs readings on final circuit of 4.4

so tested ze which was also in the same region 4.00

tested r1 + r2 which were ok (dead test) 0.25

tested ze again now a reading of 0.37

tested socket again 0.68

tested again ten min later 2.7

went next door as the two houses are feed from this house
They were the same when reading good on one house same the other and when bad so was next door.

i think a bad supply earth but can't understand why the fluctuations. When nothing moved etc

the supply is a tns as stated above feeding two houses.

any ideas

 

[Baker1988]

What earthing system is it?
Have you checked your earthing terminations

 

[Richard Burns]

I assume that the supply is actually looped from the first house to the second rather than both going through one meter.
With a TNS earth it could well be that the cable is damaged somewhere out in the road.
It could also be that the batteries are flat on your meter or you are doing a trip lock test.
However as baker says could be the earth connection at the service head that is poor, that is the first thing to check, is the earth coming form the cable sheath properly sweated in place or is it a BS951 clamp. Is the connection of this cable to the MET secure and uncorroded, are the connections from the MET to CU secure (less likely considering the supply to next house)?

If you have checked these and the Ze is still not stable then call the DNO and ensure they are aware that the Ze is unstable, they may then check again.

 

[amptest]

I assume that the supply is actually looped from the first house to the second rather than both going through one meter.
With a TNS earth it could well be that the cable is damaged somewhere out in the road.
It could also be that the batteries are flat on your meter or you are doing a trip lock test.
However as baker says could be the earth connection at the service head that is poor, that is the first thing to check, is the earth coming form the cable sheath properly sweated in place or is it a BS951 clamp. Is the connection of this cable to the MET secure and uncorroded, are the connections from the MET to CU secure (less likely considering the supply to next house)?

If you have checked these and the Ze is still not stable then call the DNO and ensure they are aware that the Ze is unstable, they may then check again.

Yes sorry it is looped from one to another

did both trip lock an no trip lock just to see
batteries new

cal ok
tester checked on my house on known zs ok every time so I assume tester ok


Extra info service cable comes into house 1 and splits to at service head
the earth coming from the cable sheath also splits to each property looks to have a clamp on it (covered in self amalgam tape) don't want to disturb it for now

from the cable sheath it goes to a met then to cu same next door.


i will contact DNO tell them it is unstable see what happens
will let you know.

 

[amptest]

What earthing system is it?
Have you checked your earthing terminations

TNS supply all terminations ok don't know about one on cable sheath don't want to disturb it

 

[amptest]

DNO came out today and told customer readings were ok
i phoned them and arranged to met them on site

reading was terrible said it was not like that earlier yeh no kidding told them that .

now replacing head and connection to cacable oh and the customer told me it was pass the blame phoned Scottish power who said no Scottish gas who than said no it councils because of house next door .

agreed to fix but said it could be tomorrow or 4 to 5 weeks

glad house is rcd protected at least that gives some protection house next door is older fuses so very bad told them to complain.

Thanks again for the replaysreplays

 

[amptest]

DNO came out today and told customer readings were ok
i phoned them and arranged to met them on site

reading was terrible said it was not like that earlier yeh no kidding told them that .

now replacing head and connection to cacable oh and the customer told me it was pass the blame phoned Scottish power who said no Scottish gas who than said no it councils because of house next door .

agreed to fix but said it could be tomorrow or 4 to 5 weeks

glad house is rcd protected at least that gives some protection house next door is older fuses so very bad told them to complain.

Thanks again for the replaysreplays

hay like the tv there not replays reply is what I typed. Stupid auto correct