Delta EB3000 Series User Manual page 460

Criteria for Earthing System and EMC
Good
Continuity of the
Safety of PE conductor
Personnel
must be ensured
throughout the
installation
Poor
High fault current
Safety of (around 1kA)
Property
Availability of
Good
Energy
Excellent
• Few
Problems:
• Need to handle
EMC Behavior
•
TN-S
Good
Continuity of the
PE conductor
must be ensured
throughout the
installation
Poor
High fault current
(around 1kA)
Good
Poor (prohibited)
• Neutral and PE
equipotential are the same
• Circulation of
disturbance
the high currents in
leaking exposed
currents conductive
problem of the parts (high
device magnetic-field
radiation)
High fault
current • High fault
(transient currents
disturbances) (transient
disturbances)
Appendix A. EMC Standard Installation GuideEB3000
TN-C
Good
RCD is mandatory
Good
Medium fault
current (< a few
dozen amperes)
Good
Good
• Over-voltage
risk
• Equipotential
Problems:
• Need to handle
the high
leaking
currents
problem of the
device
• RCD
(Residual-
current device)
A-13
TT IT
Good
Continuity of the
PE conductor
must be ensured
throughout the
installation
Good
Low current at the
first fault (< a few
dozen mA) but
high current at the
second fault
Excellent
Poor (should be
avoided)
• Over-voltage
risk
• Common–
mode filters
and surge
arrestors must
handle the
phase-to-phase
voltage.
• RCDs subject
to nuisance
tripping when
common-mode
capacitors are
present
• Equivalent to
TN system for
second fault