Smart question. I don't see polarity markings on the breaker, but then I don't even see markings to show it is good for DC. Amazon listing says 60 V DC.
You need to locate a manufacturer data sheet to determine.
Otherwise, look for a well known name that does have DC ratings, and indicates polarized or not. Midnight sells some CBI and some Carlingtech breakers. Schneider has some DC breakers.
Separately, and maybe this is what you meant by direction, breakers for AC might be intended for line on one side, load on the other. This breaker is marked "Line". Not sure, might have better protection from arcing across the two lines, except I think the poles have insulator between them. Wire connection terminals also have to have clearance (airgap) and creepage (over the surface) between them, and these UL 1077 supplementary protectors don't provide as much as UL 489 breakers.
Most reference I find refer to GFCI.
This mentions breakers suitable vs. backfed or not, but I still don't know the technical reason. A couple comments were given.
Good day! what will happen if a load is connected to the line side (and vice versa )of a circuit breaker that is not listed as interchangeable? We have this recent proj. in where the contractor did this kind of connection and cause a wire burn-out. they are claiming that the CB is...
forums.mikeholt.com
"ALL molded case breakers are suitable for back feed use UNLESS marked line and load."
"The line and load issue has to do with energized and de-energized parts when the cover of the breaker is opened and its internal parts are exposed"
"As far as I know, thermal overload mechanism is located near the load side of the CB (in a normal position), if the overheating (due to loose connection) occurs on the load side, the heat will immediately reach the TOM and will cause a trip."
