Chapter A General rules of electrical installation design

F - Protection against electric shock
10,000
1,000
500
300
250
200
150
130
100
60
40
10
t (ms)
15
30
Fig. F34 : Total discrimination at 2 levels
Fig. F35 : Total discrimination at 2 levels
A
A
60
100
RCD 300 mA
type S
Relay with separate
toroidal CT 3 A
delay time 500 ms
RCD
30 mA
Fig. F36 : Total discrimination at 3 or 4 levels
B
RCCB 1 A
delay time 250 ms
C
150
B
RCCB 300 A
delay time 50 ms
or type S
D
RCCB
30 mA
300
500
600
1,000
5 Implementation of the TT system
Discrimination at 2 levels (see Fig. F35)
Protection
b Level A: RCD time-delayed setting I (for industrial device) or type S (for domestic
device) for protection against indirect contacts
b Level B: RCD instantaneous, with high sensitivity on circuits supplying socketoutlets
or appliances at high risk (washing machines, etc.) See also Chapter P
Clause 3
Schneider Electric solutions
b Level A: Compact or Multi 9 circuit-breaker with adaptable RCD module
(Vigi NS160 or Vigi NC100), setting I or S type
b Level B: Circuit-breaker with integrated RCD module (DPN Vigi) or adaptable
RCD module (e.g. Vigi C60 or Vigi NC100) or Vigicompact
Note: The setting of upstream RCCB must comply with selectivity rules and take into
account all the downstream earth leakage currents.
Discrimination at 3 or 4 levels (see Fig. F36)
Protection
b Level A: RCD time-delayed (setting III)
b Level B: RCD time-delayed (setting II)
b Level C: RCD time-delayed (setting I) or type S
b Level D: RCD instantaneous
Schneider Electric solutions
b Level A: Circuit-breaker associated with RCD and separate toroidal transformer
(Vigirex RH54A)
b Level B: Vigicompact or Vigirex
b Level C: Vigirex, Vigicompact or Vigi NC100 or Vigi C60
b Level D:
v Vigicompact or
v Vigirex or
v Multi 9 with integrated or adaptable RCD module : Vigi C60 or DPN Vigi
Note: The setting of upstream RCCB must comply with selectivity rules and take into
account all the downstream earth leakage currents
Schneider Electric - Electrical installation guide 2008
Current
(mA)
1 1.5 10 100 500 1,000 (A)
II
I
selective RCDs
domestic S
and industrial
(settings I and II)
RCD 30 mA
general domestic
and industrial setting 0
F21
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