{"id":4250,"date":"2026-09-26T00:00:00","date_gmt":"2026-09-26T00:00:00","guid":{"rendered":"https:\/\/chac-electric.com\/?p=4250"},"modified":"2026-10-19T03:37:32","modified_gmt":"2026-10-19T03:37:32","slug":"typen-von-dc-schutzeinrichtungen","status":"publish","type":"post","link":"https:\/\/chac-electric.com\/de\/blog\/dc-circuit-breaker-types\/","title":{"rendered":"Typen von DC-Schutzschaltern"},"content":{"rendered":"

The main Typen von DC-Schutzschaltern<\/strong> used in low-voltage projects include miniature and molded-case breakers with declared DC ratings, alongside specialist designs for particular applications. The useful classification is not just the enclosure size. Identify the energy source, maximum voltage, current direction, prospective fault current and approved pole arrangement first. A device suited to one PV string is not automatically suitable for a battery bus at the same nominal voltage.<\/p>\n

\"Typen<\/p>\n

Separate breaker construction from application approval<\/h2>\n

DC MCBs are often considered for compact branch circuits; DC-rated MCCBs may offer different frame sizes, trip units and accessory options. Those are family tendencies, not guaranteed current or breaking-capacity boundaries. Read the offered model\u2019s ratings. Some devices have fixed settings and others have adjustable protection, so the letters alone do not tell you what can be configured.<\/p>\n

An isolating switch is a different product function. It may provide a means of disconnection without automatic overcurrent protection. Likewise, a remote-opening accessory does not turn an unsuitable protective device into an approved DC breaker. Write the required interruption and isolation duties separately in the equipment schedule.<\/p>\n

Treat PV and battery fault sources differently<\/h2>\n

For a PV circuit, establish the maximum system voltage under the project\u2019s temperature assumptions, string arrangement and possible reverse-current paths. For a battery circuit, establish the battery configuration, prospective fault contribution and the conditions declared for the protective device. An inverter\u2019s normal operating current does not establish the fault duty supplied by a battery.<\/p>\n

Der battery circuit protection<\/strong> review should include charging, discharging, isolation and fault states. A device that interrupts the normal discharge direction may not be suitable for reverse energy flow or every fault location. Obtain application-specific manufacturer evidence rather than treating a solar-labelled breaker as a universal DC component.<\/p>\n

Distinguish polarity from line and load direction<\/h2>\n

A polarity marking, a line\/load instruction and a declaration of bidirectional suitability are related but different pieces of information. Schneider Electric\u2019s C60H-DC FAQ states that the marked polarity must be respected and that the range should not be used where momentary current reversal can occur. That is a model-specific restriction; it should not be generalized to every DC breaker.<\/p>\n

Ask the supplier to identify permitted current direction for normal operation and interruption. If a storage system can charge and discharge through the same device, that operating mode must be covered explicitly. Do not infer bidirectional fault interruption from a non-polarized product label alone.<\/p>\n

\"CHAC-DC-Schutzschalter-Typen<\/p>\n

Read voltage and pole arrangement as one rating<\/h2>\n

Some DC devices use a manufacturer-specified series pole connection to meet a declared voltage. That connection must follow the exact diagram. Do not create a higher voltage rating by multiplying poles, improvise links or parallel poles to increase the current rating. Earthing arrangements and the fault path can affect how voltage is distributed across the interrupting poles.<\/p>\n

CHACs PXB6DC-63 DC miniature circuit breaker<\/a> und MCCB product range<\/a> provide starting points for a model enquiry. Confirm which offered device is documented for the actual DC application; a general MCCB family listing does not prove a DC rating.<\/p>\n

Keep the selection record useful for future replacement<\/h2>\n

Record the DC voltage range, pole wiring, polarity, current-direction limits, fault-current assumptions, terminal requirements and approved accessories. Include the exact catalogue number and drawing revision. This prevents a later replacement from being selected only because it fits the rail or has the same ampere marking.<\/p>\n

For the physical reason behind the different ratings, see the AC MCB versus DC MCB comparison<\/a>. Keep DC breaking capacity<\/strong> tied to the specified voltage and test conditions rather than importing an AC kA figure into a DC schedule.<\/p>\n

Which DC selection question changes with the source?<\/h2>\n\n\n\n\n\n\n\n\n
Source or operating condition<\/th>\nNachweis zu erlangen<\/th>\nUnsafe shortcut<\/th>\n<\/tr>\n<\/thead>\n
PV strings<\/td>\nMaximum voltage and reverse-current conditions<\/td>\nUsing nominal voltage alone<\/td>\n<\/tr>\n
Battery bus<\/td>\nFault contribution and interruption capability<\/td>\nSizing from normal inverter current<\/td>\n<\/tr>\n
Bidirectional storage<\/td>\nDeclared current-direction suitability<\/td>\nAssuming non-polarized means every duty<\/td>\n<\/tr>\n
Series-connected poles<\/td>\nExact manufacturer connection diagram<\/td>\nMultiplying an individual pole voltage<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\n

H\u00e4ufig gestellte Fragen<\/h2>\n

Kann ein AC-Schutzschalter auch f\u00fcr Gleichstrom verwendet werden?<\/h3>\n

Erst wenn der Hersteller ausdr\u00fccklich eine DC-Leistung f\u00fcr die erforderliche Spannung, den Strom und die Polanordnung angibt. Eine AC-Leistung reicht nicht aus, da die DC-Arschl\u00f6schung anders funktioniert.<\/p>\n

Does polarity matter on a DC circuit breaker?<\/h3>\n

It matters whenever the model has polarity or current-direction restrictions. Follow its markings and approved diagram. For a bidirectional battery circuit, obtain explicit confirmation that charging, discharging and relevant fault conditions are covered.<\/p>\n

Was sollte ein PV-Kombinationsdesigner \u00fcberpr\u00fcfen?<\/h3>\n

\u00dcberpr\u00fcfen Sie die maximale \u00d6ffnungsspannung bei minimaler Temperatur, den Kurzschlussstrom, die R\u00fcckstrompfade, die Anordnung der Strings und die DC-Unterbrechungsfestigkeit des Bremsers.<\/p>\n

Sind DC-Schutzeinrichtungen f\u00fcr Batterien geeignet?<\/h3>\n

Einige sind es, aber die Energieverbrauchsgrenze der Batterien kann die Kapazit\u00e4ten des kleinen Stromschutzes \u00fcbersteigen. Best\u00e4tigen Sie den zu erwartenden Stromverbrauch und das aktuelle Verhaltensmuster sowie die Anwendungsdaten des Herstellers.<\/p>\n

Should a DC switch be on the positive or negative conductor?<\/h3>\n

The grounding arrangement, required isolation function and manufacturer diagram decide which conductors must be switched. There is no universal positive-only or negative-only answer. A protective breaker and a disconnect must each satisfy their declared function.<\/p>\n<\/section>\n

Verweise<\/h2>\n