Viessmann Vitovalor 300-P Installation And Service Instructions For Contractors page 21

Notes on connecting to the mains supply
B
kWh
A
Z3
RCD
kWh
Z1
G
Fig. 14 Example: Selective sizing of the protective
devices
RCD (on-site) e.g. 40 A/0.5 A, 4-pole
A
On-site consumers
B
Fuse/MCB to the sub-distribution board, e.g.
C
3 x 35 A
On-site consumers
D
Vitovalor 300-P
E
RCD Vitovalor 300-P 25 A/30 mA, single pole (if
F
required)
Selective mains circuit breaker 3 x 63 A
G
Property boundary
H
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 must be at least 3 times as high as
A
that of RCD used to protect the Vitovalor 300-P.
F
Adjust the activation times of both RCDs connected in
series such that the disconnection time of RCD
less than the shortest disconnection time for RCD
Both conditions ensure that RCD
Vitovalor 300-P responds earlier than upstream RCD
A
D
RCD RCD
F
C
H
F
A
of the
F
(cont.)
E
kWh
Z2
1~
L
M N
~
400 V / 230 V~ K
Low voltage grid
K
GS protection
L
Inverter (DC/AC converter) S
M
Fuel cell stack
N
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)
is
.
l in A
Fig. 15 Response characteristics of the residual cur-
rent devices
Preparing for installation
= 1.5 kVA
EMAX
A
F
21