Recommended Circuits For Dc Systems Iec - Siemens Sentron 3VA Manual

Applications
3.4 Use of 3VA UL molded case circuit breaker in DC systems
3.4.5

Recommended circuits for DC systems IEC

GF Ground-fault monitoring
750 V DC is not a listed voltage according to UL 489
1)
Note
DC 2-pole (all-pole disconnection), grounded system
The grounded pole must always be assigned to the individual conducting path, so that in the
event of a ground fault there are always 2 conducting paths in series in a circuit with 3-pole
molded case circuit breakers, and 3 conducting paths in series in a circuit with 4-pole molded
case circuit breakers.
Note
DC 2-pole (all-pole disconnection), non-grounded system
If there is no possibility of a double ground fault occurring, or if any ground fault that does
occur is dealt with immediately (ground-fault monitoring), 500 V will be the maximum
permissible direct voltage. In a non-grounded system, all poles must be disconnected.
146
3VA molded case circuit breakers with UL and IEC certification
Manual, 01/2019, L1V30435333-01