Vetus SPP230 Manuel D'utilisation page 15

Fuses and automatic circuit break-
ers can be overloaded briefly when
appliances that require a high but
brief surge of current to start up
(such as fridges, air conditioners,
fan motors, etc.) are in use.
Various types of automatic circuit
breakers are available depending
on the application that differ in the
extent to which they can be over-
loaded. In general an automatic
circuit breaker with characteristic
B is used for domestic applications
while automatic circuit breakers with
characteristic C can also be found
in use in other applications.
According to the standard (EN 60
898) a fuse with characteristic B
must be able to accept at least three
times the nominal current value for
5 seconds and at least two times
the nominal current value for 10
seconds.
The limits for a fuse with characte-
ristic C are even slightly more than
this.
If you have a fridge, air conditioner
or other appliance that demands
a fairly high switching on current
you naturally want to be able to switch this on while still remaining within the limits of the
automatic circuit breaker.
However, most of the competitive products do not allow for this and disconnect immedi-
ately when the set value is exceeded.
The Vetus Shore Power Protector does make allowance for this possibility so that you can
continue to use your appliance in the normal way.
The Shore Power Protector even allows you to set which characteristic it should follow
when switching off - either B or C characteristic. This will usually be the B characteristic
and if you do not know what type of automatic circuit breaker is in use this is the safest
choice.
According to the official standard such a circuit breaker may also be overloaded for a
longer period provided that this is not by too much. The characteristic actually allows 20%
overloading for more than one minute. However, the Vetus Shore Power Protector will
always switch off whatever the overload, however small, if this continues for more than one
Shore power protector
120
60
I = 1.13 x I
1
40
20
10
6
4
2
1
40
20
10
6
4
2
1
0.6
0.4
0.2
B
0.1
0.06
0.04
0.02
0.01
1 1.5 2 3 4 5 6
ENGLISH
I = 1.45 x I
n 2 n
C
8 10 15 20
x I
n
090901.01
30
15