How do "Marine" circuit breakers relate to Moulded Case CBs?

latchr

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Feb 27, 2018
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I've been looking at options for a DC circuit breaker to put on my battery output. It needs to be at least 125 A at 24 V (nominal 3kW system), but given that the inverter can handle 2x rated power for some seconds, perhaps I need to be looking even higher (200A?).

I've found the "regular" kind of thing (eg Noark DC breakerhttps://www.offgridcompany.com.au/noark-2p-dc-mccb ), which seems to be called a "moulded case circuit breaker (MCCB)". These match my expectation.

However, I've also found a number of alternatives that seem to have similar current specs but are much cheaper. They are often sold as "marine" or "automotive" circuit breakers (eghttps://www.ebay.com.au/itm/DC48V-250AMP-Waterproof-Surface-Mount-Circuit-Breaker-with-Manual-Reset-Type/401304387434?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20180105095853%26meid%3Dbe79e24fa8bb4bd8bae35e1ae18c2bb4%26pid%3D100903%26rk%3D1%26rkt%3D20%26sd%3D401304387434%26itm%3D401304387434&_trksid=p2509164.c100903.m5276 ).

My gut feeling is to not trust these marine breakers for a home battery installation, because there has to be some catch with their cost being 1/5 of the MCCB. What is the story here?
 
Circuit breakers and fuses should be sized to protect the wiring, not the maximum transient overload condition of the attached equipment, and have timing characteristics to suit any start-up peaks.

Schnieder have a very high qualityDC range,and a premium price. CBi are another lesser known brand of high quality products, they sell a lot for Telco equipment use, which often appears on eBay. The DDframe range may well suit your requiment, I expect they do a rail mount version as well.

http://cbi-lowvoltage.co.za/sites/default/files/downloads/DC Catalogue 24 06 2016.pdf
 
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