Polarized vs non polarized

[JJJJ]

OK. Old topic. However wanted to clear something up.

Does polarized only allow current flow in one direction, or is this outdated information?

For instance: PV -> (combiner) -> SCC -> bus bar which feeds both batteries and inverter (hardware in between but a summary of flow)

In this case, would a polarized breaker prevent backflow from the inverter to the SCC? Or am I completely wrong here? There is a ton written about non polarized breakers and fire risks with polarized so perhaps this thinking is outdated?

My understanding is non polarized is bidirectional.

Thanks for your help

 

[ko6kL]

diodes prevent back flow,

 

[Bud Martin]

Polarized dc circuit breaker does not prevent back flow.
Polarized dc circuit breaker info:
www.altechcorp.com/PDFS/DC%20wiring_white%20paper_Altech%20DC%20series_0813.pdf

 

[timselectric]

Polarized breakers can only extinguish the arc in one direction. They don't control the direction of flow.

 

[JJJJ]

So is there ever a reason in DC applications where a polarized breaker is used?

 

[HRTKD]

My limited understanding is that the polarized breaker will allow current to flow both ways, until it won't, at which time you have a problem. I've used the polarized breakers for very specific loads where I know the power is going to flow only in one direction. Was a polarized breaker necessary? No, but it's what would work for me given time constraints, cost, quality, specifications (amps) and availability.

 

[timselectric]

They are usually cheaper.

 

[Supervstech]

So is there ever a reason in DC applications where a polarized breaker is used?

AFAIK, the polarized breakers are used when an arc fault from a large power source is needing protection.