ABB ACS 600 Hardware Manual page 12

Safety Instructions
Components
Connected to Digital/
Analogue Inputs
EMC
x ACx = ACS/ACC/ACP
WARNING! IEC 664 requires double or reinforced insulation between
live parts and the surface of accessible parts of electrical equipment
which are either non-conductive or conductive but not connected to the
protective earth.
To fulfil this requirement, the connection of a thermistor (and other
similar components) to the digital inputs of ACx 600 can be
implemented in three alternate ways:
1. There is double or reinforced insulation between the thermistor and
live parts of the motor.
2. Circuits connected to all digital and analogue inputs of the ACx 600
are protected against contact, and
insulated with basic insulation (the same voltage level as the
converter main circuit) from other low voltage circuits.
3. An external thermistor relay is used. The insulation of the relay must
be rated for the same voltage level as the converter main circuit.
Installing control instruments (contactors or relays) or control cables
other than those of the ACx 600 inside the frequency converter (drive
enclosure) is not acceptable.
Note: If safety switches, contactors, connection boxes or similar
equipment are used in the motor cable, they should be installed in a
metal enclosure with 360 degrees earthing for the screens of both the
incoming cable and the outgoing cable, or the screens of the cables
should otherwise be connected together.
WARNING! The printed circuit boards contain integrated circuits that
are extremely sensitive to electrostatic discharge. Exercise appropriate
care when working on the unit to avoid permanent damage to the
circuits. Do not touch the boards unnecessarily.
ACS/ACC/ACP 604/607 Frequency Converters