Haven't seen it happen with a breaker, but I've seen plenty of relay contacts fuse. One of the things to watch for is that the CBs have a high enough voltage rating, and are rated for DC not AC. The higher-voltage ones have "blow-out magnets" to help extinguish the arc when the contacts snap open, but I can imagine the scenario where the contacts are partially made (as in during a manual reset attempt), which could cause arc-welding of the contacts.
I agree that Class T fuses are a better choice for battery banks. Having seen the quality of products put out by Blue Sea Systems I think it's safe to assume their engineering folks know what they're talking about.
Jim
--- In electricboats@yahoogroups.com, "Tom" <boat_works@...> wrote:
>
> The Oct/Nov issue of Professional Boatbuilder magazine has an article on
> the design and installation of large battery banks.
>
> In a side bar, the author discussed protection of large banks with Wayne
> Kelsoe, VP of electrical engineering at Blue Seas Systems. Among the
> author's conclusions is that Class-T fuses are preferred over circuit
> breakers for protecting large battery banks.
>
> ..."a common failure mode after a short-circuit fault is for the
> contacts to fuse when reset. How many of us have reset a circuit breaker
> without investigating the cause? If the fault still exists, and the
> over-current protection is compromised, a fire could result. At the very
> least, the breaker will be internally damaged, and will not reset,
> allowing the circuit to remain open. Boat operators often carry spare
> fuses, but how many carry spare primary circuit breakers?"
>
> Anybody in the group had any experience with the type of circuit breaker
> failure that Wayne is talking about?
>
> -Tom
>
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