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6LE007331A
The types of protection device
3.5 Ground fault protection
Ground fault protection provides protection against high-intensity phase-to-earth fault currents
present in installations with a TN-S earthing system. It is based on the sum of the phases and
the neutral current. The time delay is adjustable.
Ground fault protection curve
I (A)
t (s)
tg
lg
l²tg
Ground protection
Ground fault protection parameters
G
Ig (xIn)
Ground protection threshold
tg (s)
Ground Fault protection time delay
I²tg (ON / OFF)
Inverse time I²t function
Adjusting the Ig pick-up setting
The Ig pick-up is adjusted using the Ig adjustment dial.
Ig pick-up adjustment range (x In)
OFF
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
1.0
When the Ig pick-up is set to OFF, ground fault protection is deactivated.
Adjusting the tg time delay
The tg time delay is adjusted using the tg adjustment dial.
tg time delay adjustment range (s)
0.05
0.10
0.20
0.40
0.60
Non-tripping time (s)
0.025
0.075
0.175
0.375
0.575
Maximum tripping time (s)
0.1
0.15
0.25
0.45
0.65
Maximum breaking time (s)
0.12
0.17
0.27
0.47
0.67
Ground fault protection provides protection against high-intensity phase-to-earth fault
currents. It is similar to short time delay protection. It also has an I²t inverse time function,
which can be activated or deactivated while adjusting this protection.
This I²t function makes it possible to improve the selectivity of ground faults with downstream
devices. It is activated from the Ig pick-up and functions up to In.
ATTENTION
In the case of a 3-pole product, the ground fault protection is dependant on the neutral
protection setting and on the presence of an ENCT external neutral current sensor. If
an ENCT external neutral current sensor is used, it is necessary to activate the neutral
protection to take into account the sum of the phases and the neutral current.
