Recommended circuit configurations for DC systems


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.


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.

Further circuits are available on request.


Ground-fault monitoring


Ue > 250 V DC: DC insulating plate is mandatory for sizes 3VA10 and 3VA11 with a non-insulated mounting plate (see chapter Insulating equipment)