Megger Limited
PWS / Nov 06
DET4TC/R Launch
23
“STAKELESS” Earth Electrode Testing
Earth electrode testing can be a difficult and time-consuming business; this is why
Megger is committed to making life as easy as possible for you. Our experience of
real life situations led to the introduction of
ART
, first seen with the
DET3TC
, and
now with the
DET4TC
we add the capability to perform
Stakeless
measurements.
Adding a second clamp, the
VCLAMP
, the
DET4TC
can be used to measure
electrode resistance in locations where driving stakes is not practical.
To take a measurement simply select the dual clamp range on the
DET4TC
, connect
the
ICLAMP
and the
VCLAMP
to the appropriate terminals. Then clamp both of them
around the electrode under test (or the cable connected to the electrode) and press
the test button, simple. However there are a few simple things to remember.
The first is that there must be at least 100mm gap between the clamps. This is to
ensure the field around the clamps do not interfere with each other. The result would
be incorrect readings.
Lets take a look at the test in practice:
Current is induced into the circuit by the
ICLAMP
and then the resulting voltage is
measured with the
VCLAMP
. From this the resistance of the compete loop / current
path can be measured.
The important thing to remember is that the method measures the resistance of the
total loop, where the test current in flowing. Therefore it is important to understand
the path the test current is taking.
Gr ound
Elec tr ode
Under
Test
Building ear th
connec tion/s
ICLAMP
VCLAMP
