Converter Operation On A Grounded Network; Connect Metal Shield In The Terminal Box - Siemens SIMOTICS M-1PH8 Operating Instructions & Installation Instructions

Electrical connection
6.4 Auxiliary circuits
6.4.9

Converter operation on a grounded network

CAUTION
Damage resulting from protective conductor currents
When the machine is operated on a converter with current limiter, but without ground-fault
monitoring, protective conductor currents of up to 1.7 times the external conductor current
can arise if there is a ground fault on the output side. Neither the PE conductors of normally
rated multi-core connecting cables nor the PE connecting points of normal terminal boxes
are suitable for this purpose. Material damage can result.
● Use an appropriately sized PE conductor.
● Connect the PE conductor to the grounding terminal on the motor enclosure.
6.4.10

Connect metal shield in the terminal box

If you are using metal-armored cables that are inserted into the terminal or auxiliary terminal
boxes, then the metal shield is connected as follows:
● Ensure that the metal shield is grounded only once: either in the terminal box or in the
● In terminal boxes with an internal grounding component, connect the metal shield to the
● In terminal boxes without an inner grounding component, connect the metal shield to one
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control room of the operator.
If you connect in the control room, then the connection in the terminal box is not permissible:
the following points do not apply.
inner grounding component, if it is not grounded in the control room.
of the green-yellow grounding terminals, if it is not grounded in the control room.
WARNING
Explosion hazard for multiple grounding
If the metal shield is grounded more than once, it may form an electrical loop. In an
explosive atmosphere, there is a risk of an explosion. This can result in death, serious
injury or material damage.
Ground the metal shield only once.
Operating Instructions 05/2012 A5E03986435A AA
SIMOTICS M-1PH8