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2.
Installation and wiring
2.5 Fitting the CTs to the measuring wires
When monitoring one circuit with 1-phase 2-wire, you need one CT. When monitoring one circuit with 1-phase 3-wire,
you need 2 CTs. When monitoring one circuit with 3-phase 4-wire, you need 3 CTs. The following diagram is an
example of fitting CTs when monitoring one circuit with 1-phase 2-wire.
• For details about how to connect the CTs to the measuring wires, refer to the manual of the CTs you are using.
• Fit the CTs to the measuring wires after connecting the CT cables to the unit.
• Attach to the L-phase if measuring 1-phase 2-wire.
Attach to the R-phase and T-phase if measuring 1-phase 3-wire or 3-phase 3-wire.
Attach to the R-phase, S-phase, and T-phase if measuring 3-phase 4-wire.
• Refer to "2.8 Wiring diagrams (
35)" for more on attaching CTs according to the phase and wire types.
• The CT has polarity. Confirm the directions from the power side (K) to the main unit side (L) before connecting it.
You will be unable to measure correctly if you make a mistake with the directions.
Important
• Electric shock may occasionally occur.
Always make sure that the power is turned OFF before connecting the CT.
• Make sure that the primary electrical wire clamped at the CT is insulated coated wire.
• Do not expose the CTs to excessive vibrations or impacts.
CT
Power side
Main unit side
Main
unit
Breaker
L
N
K
L
