How To Attach The Current Transformer (Ct) - Panasonic KW2G User Manual

3.6 How to attach the Current Transformer (CT)

・One CT is needed for 1 unit when measuring 1P2W (2 CTs for 2-circuit). Two CTs are needed when
measuring 1P3W/3P3W. Using all CTs for one unit should be the same.
・Check beforehand that the thickness of the electric wire is smaller than the through-hole of the CT.
・When connecting CT, connect the secondary side to the terminal of the main unit first, and after that
wire the primary side to a load electric wire. Incorrect order might cause an electric shock or break CT.
・The CT has polarity. Wire correctly according to the K and L marks. Wrong direction can't measure
correctly.
・When closing CT, check that there is no foreign materials on the divided face. And make sure it is
closed securely once the wire is in place; if not the measurement value will be not accurate.
・When CT's cable is extended, it is possible to extend up to about 10m with the cable of AWG#22 or
more cross section under the environment without noise at all. Please use the thick cable as much as
possible.
・Separate the wiring (strong electric part) of the measured voltage input terminal (operating power
supply terminal) from the CT cable. It may not satisfy the accuracy due to noise.
・Only same color housing of cable and connector of CT can be connected.
That of different color (blue and white) can't be connected.
◆To connect CT with secondary side current 5A
How to set for measuring by combination with CT (secondary side current 5A)
(1) Select 5A at CT type setting mode (CT-T).
(2) Set the primary current of measured CT (secondary side current 5A) at primary side current of
CT setting mode (CT-1).
<ex> If the measured CT is 400A/5A, set to '400'.
(3) Clamp the dedicated CT for 5A (AKW4801C), which is connected to the main unit first, to
secondary side of the CT (secondary side current 5A). CT direction (K→L) should be set for the
commercial CT direction.
*Set the CT (secondary side current 5A) and the dedicated CT for 5A approximately 1m apart.
If the two CTs are set too close each other, it may not measure accurately due to magnetic
field interference.
(Connection example)
With Ammeter etc.
Power supply
Breaker
Load
Secondary current
K
CT with 2nd current 5A
L
Ammeter etc.
L K
Dedicated CT for 5A
17
KW2G / KW2G-H Eco-POWER METER
Eco-POWER
METER