Brymen BM161s User Manual page 6

5
ACA & DCA Current clamp-on function
Inputs are made through the clamp jaws for non-invasive ACA & DCA current
measurements.
CAUTION (Application and removal of the Clamp-on meter)
Press the jaw trigger and clamp the jaws around only one single conductor of a circuit
for load current measurement. Make sure the jaws are completely closed, or else it will
introduce measurement errors. Enclosing more than one conductor of a circuit will
result in differential current (like identifying leakage current) measurement. Locate the
conductor(s) at the Jaws center as much as possible to get the best measuring
accuracy. The jaw arrow-mark indicates current flow direction on DCA positive
readings. For removal, press the jaw trigger and remove the jaws from the
conductor(s).
Note: In DCA measurements, hysteresis of the jaws (after measuring high DC currents)
may introduce non-zero residual readings. Relative Zero mode should be used to
offset the residual readings, if any, so as to get more accurate measurements.
Adjacent current-carrying devices such as transformers, motors and conductor wires
will affect measurement accuracy. Keep the jaws away from them as much as possible
to minimize influence.