3 Copper tests
ARGUS Copper Test Manual
25
Special features for RE (Examples):
1a. Measuring site, e. g. demarcation point:
The demarcation point is not earthed. The Copper box (GND socket) is disconnected from
the shielding terminal of the demarcation point. The measurement works when the cable
shield os continuous. The displayed RE measurement is the R-cable shield (Rshield). The
measurement works even if e. g. a shield terminal in the earth cable becomes high-ohm
due to an installation error or a lightning strike. This can then be recognised from the high
RE measured value.
1b. However, if the cable shield is not continuous (see image) or too high-ohm, the
measurement will no longer function (RE>10 kΩ).
As a remedy, the reistance symmetry measurement can be conducted using the building
potential equalisation rail or an earthed metal water or heating pipe. If this is not possible
either, trained electricians can, after checking the building configuration (TN-S, TT), use the
PE (protective ground) line as an earthing point after verifying thar it is voltage-free. In gen-
eral, attention must be paid to ensuring secure contact, particularly to oxidised or corroded
earthing points.
The measurement does not work when the earthing is interrupted at one of the connection
points. However, it will work for a poor ground connection. Reason for cancellation of mea-
surement (RE >10 kΩ).
