Were I to guess, their reasoning is their DC circuitbreaker is designed to better accomodate that erosion in one direction versus the opposite.
It is a safety device afterall. A prudent design would strive to make that device as long lived and reliable as practical.
Today, as I was researching DC circuit breakers again, I stumbled across this article that says that the DC Blue Seas breakers must be wired with proper "polarity", contrary to my previous conclusion.
"Reversing polarity would result in safety issues and irreversible damage."
"Direct currents flow has one and one only ‘unidirectional’ flow of electrical charge one [sic] a constant direction, e.g. batteries or solar cells so the DC circuit breaker must respect that one direction charge."
https://marinesupplydock.wordpress.com/ ... kers-acdc/
[sic] In the quote, I think that the term "one" should read "in" … a constant direction. Meaning, current flows in one direction.