{"id":33599,"date":"2026-09-16T07:18:06","date_gmt":"2026-09-16T07:18:06","guid":{"rendered":"https:\/\/fenchenergy.com\/?post_type=product&p=33599"},"modified":"2026-10-26T01:21:02","modified_gmt":"2026-10-26T01:21:02","slug":"300a-dc-circuit-breaker-mccb-diy-batteriebox","status":"publish","type":"product","link":"https:\/\/fenchenergy.com\/lb\/product\/300a-dc-circuit-breaker-mccb-diy-battery-box\/","title":{"rendered":"300A DC Circuit Breaker MCCB fir DIY Batterieboxen | 2-Pole Batterie Isolator, EU Lager"},"content":{"rendered":"
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E 300A DC Circuit Breaker m\u00e9cht eng Aufgab, d\u00e9i \u00c4re BMS net eleng maache kann: en g\u00ebtt Iech eng physesch \u00cbnnerbriechung am Circuit.<\/strong> \u00c4re BMS sch\u00fctzt d'Zellen g\u00e9int Iwwerstrom an Kuerzschl\u00e9i, mee wann Dir um Pack schafft, den Inverter isol\u00e9iere musst oder d'Kraaft an engem Noutfall ofschalte w\u00ebllt, braucht Dir eppes wat Dir tats\u00e4chlech ausschalte k\u00ebnnt. D\u00ebsen 2-Pole DC Breaker s\u00ebtzt t\u00ebscht \u00c4rer Batterie an \u00c4rem Inverter, f\u00fc\u00fcgt Kuerzschluss-Schutz iwwer dem BMS derb\u00e4i, an g\u00ebtt Iech e sichtbaren Disconnect-Punkt.<\/p>

Firwat e 300A DC Circuit Breaker besser ass w\u00e9i n\u00ebmmen op de BMS ze vertrauen<\/h3>

E BMS ass e Schutzapparat, kee Schalter. Hien schneit de Stroum of wann eppes falsch leeft, mee hie l\u00e9isst Iech net de Pack op Ufro isol\u00e9ieren \u2014 an hie kl\u00e4ert och kee schw\u00e9iere Kuerzschluss um Haapt-DC-Feed w\u00e9i e Breaker et m\u00e9cht. E Breaker derb\u00e4isetzen g\u00ebtt Iech dr\u00e4i Saachen, d\u00e9i e BMS eleng net kann:<\/p>

  • Eng manuell Disconnect<\/strong> fir \u00cbnnerhalt, Upgrades an Noutf\u00e4ll<\/li>
  • Kuerzschluss-Kl\u00e4ren<\/strong> bew\u00e4ert op 7.5kA<\/li>
  • E Feeler deen Dir gesitt<\/strong> \u2014 e ausgel\u00e9iste Breaker weist Iech datt eppes geschitt ass, amplaz Iech ze loossen raten<\/li><\/ul>

    AC Breaker geh\u00e9ieren net op eng Batterie Circuit<\/h4>

    D\u00ebst ass de wichtegste Feeler. Altern\u00e9ierende Stroum pass\u00e9iert 50-60 Mol d'Sekonn duerch Null, an d\u00ebse Null-Duerchgank erlaabt engem AC Breaker den Bogen auszeschalten wann en ausgel\u00e9ist g\u00ebtt. Gl\u00e4ichstroum huet keen Null-Duerchgank, sou datt de Bogen weiderbrennt. E AC Breaker kann e Feeler op engem Batterie-System net kl\u00e4ren, wat genee d\u00e9i Situatioun ass, d\u00e9i e Breaker soll l\u00e9isen.<\/p>

    E 300A DC Circuit Breaker fir h\u00e9ich-Output Systemer auswielen<\/h3>

    300A ass d'Top vun d\u00ebser Serie. Wielt et wann \u00c4re System wierklech op deem Niveau leeft:<\/p>

    • Dir benotzt e 300A BMS<\/strong><\/li>
    • Dir hutt en Inverter deen no bei der BMS-Grenz zitt<\/strong> kontinu\u00e9ierlech<\/li>
    • Dir sidd m\u00e9i w\u00e9i ee Inverter am Gebrauch<\/strong>, oder plangt ee derb\u00e4izesetzen<\/li>
    • \u00c4re Lastprofil ass h\u00e9ich an dauerhaft<\/strong> rather than short bursts<\/li>
    • You want no margin compromise<\/strong> \u2014 the breaker stays above everything downstream<\/li><\/ul>
      Your BMS \/ system<\/th>Model to choose<\/th><\/tr><\/thead>
      200A BMS \u2014 the standard DIY build<\/td>BCPS2DM220, 220A<\/td><\/tr>
      250A BMS, or 200A BMS with surge-heavy loads<\/td>BCPS2DM250, 250A<\/td><\/tr>
      300A BMS and high-output systems<\/strong><\/td>BCPS2DM300 \u2014 this model, 300A<\/strong><\/td><\/tr><\/tbody><\/table><\/div><\/div>

      One warning that matters more than the table: at 300A the cable becomes the bottleneck.<\/strong> A 300A breaker does not make an undersized cable safe \u2014 size the cable for the current first, and make sure your terminals and busbars are rated for it too.<\/p>

      Reading the Label: DC Rating and Breaking Capacity<\/h3>
      Marking<\/th>What it means<\/th><\/tr><\/thead>
      125\/250V DC<\/strong><\/td>DC voltage rating \u2014 125V per pole, 250V with both poles<\/td><\/tr>
      2P<\/strong><\/td>Two poles, breaking together<\/td><\/tr>
      300A<\/strong><\/td>Rated continuous current<\/td><\/tr>
      Icu\/Ics 7.5kA<\/strong><\/td>Short-circuit breaking capacity<\/td><\/tr>
      IEC 60947-2<\/strong><\/td>The switchgear standard the device is marked to<\/td><\/tr><\/tbody><\/table><\/div><\/div>

      Fitting a DC Circuit Breaker Into a DIY Battery Box<\/h3>

      At 78 \u00d7 38 \u00d7 63mm and 225g, this breaker fits inside a battery enclosure or a tight cabinet instead of needing its own panel.<\/p>

      1. Mount it where you can reach it.<\/strong> A breaker you cannot access is decoration.<\/li>
      2. Follow the LINE and LOAD markings<\/strong>, and confirm the wiring diagram in the manual before connecting.<\/li>
      3. Torque the terminals to spec<\/strong> and re-check after the first thermal cycle.<\/li>
      4. Keep AC and DC separate.<\/strong> This device goes on the DC side between battery and inverter; the AC output side needs its own AC breakers.<\/li>
      5. Check heat at full load.<\/strong> High-current builds warm up; leave airflow around the breaker and check terminal temperature after the first hour at full load.<\/li><\/ol>

        Spezifikatioune<\/h3>
        Parameter<\/th>Spezifikatioun<\/th><\/tr><\/thead>
        Modell<\/td>BCPS2DM300<\/td><\/tr>
        Typ<\/td>2-pole DC circuit breaker (MCCB)<\/td><\/tr>
        Rated current<\/td>300A<\/td><\/tr>
        Voltage rating<\/td>125\/250V DC<\/td><\/tr>
        Breaking capacity<\/td>Icu\/Ics 7.5kA<\/td><\/tr>
        Poles<\/td>2<\/td><\/tr>
        Dimensiounen<\/td>78 \u00d7 38 \u00d7 63mm<\/td><\/tr>
        Gewiicht<\/td>225g<\/td><\/tr>
        Application<\/td>Short-circuit protection and manual isolation for battery boxes<\/td><\/tr>
        Standard marking<\/td>IEC 60947-2<\/td><\/tr>
        OEM \/ ODM<\/td>Supported<\/td><\/tr>
        Liwwerung<\/td>EU Lager, DDP Liwwerung aus Polen<\/td><\/tr><\/tbody><\/table><\/div><\/div>

        Net abegraff:<\/strong> the battery box, the BMS and the battery cells. This listing is the circuit breaker only.<\/p>

        FAQ<\/h3>

        Which systems need a 300A DC circuit breaker?<\/strong>
        300A BMS builds, systems with inverter loads running close to the BMS limit, and installations with more than one inverter.<\/p>

        Can I use a smaller breaker to save money?<\/strong>
        No. A breaker rated below your system’s continuous current will nuisance-trip. Size at or just above your continuous current.<\/p>

        Can I use an AC breaker on a battery circuit instead?<\/strong>
        No. DC arcs do not self-extinguish, so an AC breaker may fail to clear a fault. This device is DC-rated at 125\/250V DC.<\/p>

        How much short-circuit current can it clear?<\/strong>
        7.5kA (Icu\/Ics).<\/p>

        Will it fit inside my battery box?<\/strong>
        At 78 \u00d7 38 \u00d7 63mm and 225g it fits most DIY enclosures. Send us the mounting space if you are unsure.<\/p>

        Do you make other ratings?<\/strong>
        Yes \u2014 220A (BCPS2DM220) and 250A (BCPS2DM250) in the same series.<\/p>

        Does it come with the box, BMS or cells?<\/strong>
        No. This listing is the breaker only.<\/p>

        Related: Battery Box Parts and Accessories<\/h3>

        Building a complete pack? Pair the breaker with a DIY battery box kit, a battery box base, a set of battery box wheels, and a JK BMS heating pad if you charge in cold weather. Cells in 280Ah, 314Ah and 320Ah are available from the same warehouse.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>","protected":false},"excerpt":{"rendered":"

        \ud83d\udd0c 300A DC Circuit Breaker MCCB \u2014 2-Pole Batterie-Isolator<\/strong>
        \n\u2705 DC-bew\u00e4ert 2-Pole Circuit Breaker fir DIY Batterie-K\u00ebschten | 125\/250V DC
        \n\u26a1 300A bew\u00e4ert | Icu\/Ics 7.5kA Kuerzschluss-Breaking-Kapazit\u00e9it
        \n\ud83d\udd17 Fir 300A BMS Konstruktiounen an h\u00e9ich-Output Systemer
        \n\ud83d\udcd0 Kompakt 78 \u00d7 38 \u00d7 63mm | 225g | install\u00e9iert bannent dem Geh\u00e4is
        \n\u26a0\ufe0f Circuit Breaker n\u00ebmmen \u2014 K\u00ebscht, BMS an Zellen sinn NET abegraff
        \n\ud83d\ude9a EU Stock | Polen Lager<\/p>","protected":false},"featured_media":33607,"comment_status":"open","ping_status":"closed","template":"","meta":[],"product_brand":[],"product_cat":[305],"product_tag":[],"class_list":["post-33599","product","type-product","status-publish","has-post-thumbnail","product_cat-accessories-parts","first","instock","shipping-taxable","purchasable","product-type-simple"],"_links":{"self":[{"href":"https:\/\/fenchenergy.com\/lb\/wp-json\/wp\/v2\/product\/33599","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fenchenergy.com\/lb\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/fenchenergy.com\/lb\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/fenchenergy.com\/lb\/wp-json\/wp\/v2\/comments?post=33599"}],"version-history":[{"count":1,"href":"https:\/\/fenchenergy.com\/lb\/wp-json\/wp\/v2\/product\/33599\/revisions"}],"predecessor-version":[{"id":34238,"href":"https:\/\/fenchenergy.com\/lb\/wp-json\/wp\/v2\/product\/33599\/revisions\/34238"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/fenchenergy.com\/lb\/wp-json\/wp\/v2\/media\/33607"}],"wp:attachment":[{"href":"https:\/\/fenchenergy.com\/lb\/wp-json\/wp\/v2\/media?parent=33599"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/fenchenergy.com\/lb\/wp-json\/wp\/v2\/product_brand?post=33599"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/fenchenergy.com\/lb\/wp-json\/wp\/v2\/product_cat?post=33599"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/fenchenergy.com\/lb\/wp-json\/wp\/v2\/product_tag?post=33599"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}