Viessmann C3TB, Installation And Service Instructions For Contractors

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RCD RCD
kWh
Z1
H
400 V / 230 V~ K
D
F
RCD
A
B
C
G
kWh
Z2
1~
E
L
~
N M
kWh
Z3
Fig. 14 Example: Selective sizing of the protective
devices
A
RCD (on-site) e.g. 40 A/0.5 A, 4-pole
B
On-site consumers
C
Fuse/MCB to the sub-distribution board, e.g.
3 x 35 A
D
On-site consumers
E
Vitovalor 300-P
F RCD Vitovalor 300-P 25 A/30 mA, single pole (if
required)
G Selective mains circuit breaker 3 x 63 A
H
Property boundary
K
Low voltage grid
L
GS protection
M
Inverter (DC/AC converter) S
EMAX
= 1.5 kVA
N
Fuel cell stack
Z1 Balancing bi-directional meter (observe meter cir-
cuit)
Z2 Net electricity meter (standard delivery
Vitovalor 300-P)
Z3 Bi-directional energy management (not relevant for
billing by the grid operator)
Ensure adequate selectivity if any new RCD is instal-
led downstream of any existing circuit breaker. In order
to ensure complete selectivity of two residual current
devices connected in series, the fault current of
upstream RCD
A must be at least 3 times as high as
that of RCD F used to protect the Vitovalor 300-P.
Adjust the activation times of both RCDs connected in
series such that the disconnection time of RCD
F
is
less than the shortest disconnection time for RCD
A
.
Both conditions ensure that RCD
F
of the
Vitovalor 300-P responds earlier than upstream RCD
A
l in A
t in s
A
F
Fig. 15 Response characteristics of the residual cur-
rent devices
Preparing for installation
Notes on connecting to the mains supply
(cont.)
5775 636 GB
Installation