Tracing 3-phase earth-leakage causes ?

[n***@motz.invalid]

The maintenance man in this office block can't find the
error-cause on the 6th floor, which trips even at night,
when the offices are not occupied. When the problem is
detected, its cause has disapeared.

Each floor has a single earth-leakage safety detector, for all
the offices of different tenants.

I think that the phases are divided amongst the different tenants.

On my floor/office the light and plugs are on different phases,
because when we had similar problems, I just put my computer
on the light circuit, to avoid problems from the plugs
tripping-out.
------------

My thinking is that this is a very dificult problem to diagnose ?

The 3-phase EL-detector is 25mA [for the 220V here].
And a rat/s or carbonned-over contact which crosses the 25mA
threshold when humidity...etc. changes ...etc. could be the
problem cause ?

How do the professionls handle such problems, other than
having an EL-unit for each separate tenant ?

== TIA.




Although this NewsGroup still functions well,
there are already many other previously good
NewsGroups which have been crowed-out by
the twittering-idiot-masses. To avoid further
displacement of the NNT-protocol by the
dumbed-down inefficient clik-blogs, we need
to take a stand.

[Andrew Gabriel]

Post by n***@motz.invalid
The maintenance man in this office block can't find the
error-cause on the 6th floor, which trips even at night,
when the offices are not occupied. When the problem is
detected, its cause has disapeared.
Each floor has a single earth-leakage safety detector, for all
the offices of different tenants.
I think that the phases are divided amongst the different tenants.
On my floor/office the light and plugs are on different phases,
because when we had similar problems, I just put my computer
on the light circuit, to avoid problems from the plugs
tripping-out.
------------
My thinking is that this is a very dificult problem to diagnose ?
The 3-phase EL-detector is 25mA [for the 220V here].

No idea where _here_ is, but in the UK, having a single
earth-leakage detector of such a low value covering
many separate circuits and tenants would not be permitted,
for exactly this reason.