Mitsubishi Electric MELSEC-Q QE81WH4W User Manual page 4


When using this product, make sure to use it in combination with current sensor (EMU-CT□□□
series or EMU2-CT5-4W) and Voltage transform unit (QE8WH4VT). Please not to exceed the
ratings of this product for input of current sensor. For further details, please refer to current sensor
manual to maintain the functionality and the accuracy of this product. The available range of the
voltage transform unit is from 63.5/110 to 277/480V AC. When used in a circuit more than
227/480V AC, voltage transformer is required.

Current sensor (EMU-CT50, EMU-CT100, EMU-CT250, EMU-CT400, EMU-CT600) is used only
for low voltage circuit. It cannot be used with a high voltage circuit. Also, EMU2-CT5-4W should be
used with the secondary side (5 A) of transformer transfixed. If it is connected with a high-voltage
circuit by mistake, it may cause a burnout of the device and a fire. It is critically dangerous. For the
Allowable maximum voltage, refer to Appendix 2 "Option devices".

Current sensor has a polarity (directionality). Be careful about it when installing the module.

Do not open the secondary side of current sensor.

Take care not entering any foreign objects such as chips and wire pieces into the module. It may
cause a fire, failure or a malfunction.

In order to prevent the module from incoming foreign objects such as wire pieces during wiring
work, a foreign-object preventive label is placed on the module. While a wiring work is performed,
keep the label on the module. Before operating the system, peel off the label for heat release. If
the foreign-object preventive label is not peeled and the system is in use, residual heat inside the
module may reduce the product life.

The wires to be connected to the module shall be put in a duct or fixed together by clamp. If not,
the loosing and unstable wire or careless stretching results in poor contact of electric wires. That
may cause a breakage of the module or wire or a malfunction.
 Use appropriate size of electric wires. If inappropriate size of electric wire is used, it may cause a
fire due to generated heat. For appropriate size of electric wires, refer to 7.4.2 How to connect
wires (
P7-6).

In case using stranded wire, take measures so that the filament should not vary by using a bar
terminal or by processing the point twisted. Use the bar terminal appropriated for the size of
electric wires. If using inappropriate bar terminals, a wire breakage or a contact failure may cause
a device malfunction, failure, a burnout or a fire.

After wiring, confirm whether there is a wiring forgetting or a faulty wiring. They may cause a
device malfunction, a fire, or an electric shock.

When removing the wires connected to the module, do not pull wires as holding on their electric
wire portions. Push the buttons on the terminal, and then remove the wire.

If the wires connected to the module are strongly pulled off, it may cause a malfunction or a
breakage to the module or the wire. (Tensile load: 22N or less)

Ensure the wiring to the module properly, checking the rated voltage and current of the product
and the terminal pin assignment. If the input voltage exceed the rated voltage or the wiring is
improper, it may cause a fire or a breakage.

Do not exceed the specified voltage when doing an insulation resistance test and a commercial
frequency withstand voltage test.

To protect persons who do not have adequate knowledge of electric equipment from elevtric
shocks, any of the following measures should be taken for the panel.
(a) To lock the panel so that only trained persons having adequate knowledge of electric equipment
can open it.
(b) To design the structure so that the power is automatically interrupted upon opening of the panel.
The protection class of the panel should be IP2X or higher.
CAUTION
A - 3