¶ APPENDIX D. ELECTRICAL CONNECTION ACCORDING TO DIRECTIVE 2004/108/EC — EMC
Recommendations for Proper Installation from the EMC Perspective
The most common source of interference is frequency converters or switched power supplies for electric heating. To eliminate interference, it is recommended to use sine filters, which should be connected to or before the control panel on the power cable if the frequency converters or electric heating are powered from the control panel. If the frequency converters or electric heating are powered from outside the control panel, the sine filter must be placed directly at the frequency converters or electric heating.
Motor Cables
Cables to frequency converters must be routed separately.
Since the leakage current of frequency converters exceeds 3.5 mA, reinforced protective grounding must be connected.
According to EN 50178 requirements, the cross-section of the grounding cable must be at least 10 mm² or two separate protective conductors must be used.
The sine filter should be connected as close as possible to the output of the frequency converter. Shielded cables should be used to connect the filter and converter.
Poor
Execution
Disruption
of shielding
without further
measures
Execution
The effectiveness
of shielding
is limited
Grounding
of shielding
through eyes
A: I shielding
For shielded cables, it is recommended to use metal bushings.
Inadequate grounding of the entire device may cause balancing currents to flow through the double-grounded shielding. These balancing currents can cause interference.
The assumption for double grounding of the shielding is therefore: Sufficient potential balancing (minimum 16 mm²).
Avoid grounding with braiding.
For serial communication, it is recommended to use twisted pair cables.
A: Frequency Converter
B: Correct Grounding
A: Frequency Converter
B: Poor Grounding