3-5
IM CW120-E
Precautions for Safe Measurement
3
3.3
Maintaining High Precision of
Measurement
To achieve a high precision of measurement, use the CW120/121 under the
following conditions.
• Ambient temperature:
23° ±5°C
• Ambient humidity:
35 to 75% RH (no condensation)
When installing the CW120/121 in a location where the ambient relative
humidity is 30% or less, use such equipment as an anti-static mat to prevent
electrostatic discharge.
If you move the CW120/121 from an area of low temperature and humidity to
an area of high temperature and humidity or if there is a sudden change in the
ambient temperature, condensation may occur in the meter. If this happens,
let the meter stand for at least one hour to allow it to adapt to the new ambient
temperature and for condensation to evaporate. Then, start operating the
meter.
●
Relationship between Clamp and Conductor
1. When performing a measurement, hold the clamp-on probe so that the
conductor cable runs through the center of the clamping CT.
2. Ensure that the orientation of the clamp to the direction of the conductor
cable (from the power supply to the load) is correct, as shown in the figure.
3. Ensure that the clamping CT is properly closed.
Conductor cable
Power supply source side
Load side
Clamping CT
Joint section
