Why is MCCB 1000Vdc for photovoltaic?
Why is MCCB 1000Vdc for PV?


That is a matter of opinion. For whatever reason UL determined there was a need to have a standard that specifically covers circuit breakers for PV applications.


  What is the difference between UL489 and UL489B?


UL489 covers circuit breakers for general use with exceptions and supplemental requirements for specific uses covered in the standard. UL 489A covers circuit breakers for use in communications equipment. UL 489 B covers circuit breakers for PV systems.


  Is it okay to use the 1000Vdc PV MCCB for my 750Vdc traction application?


No. Items intended for specific uses either by UL standard number designation or by manufacturer designation are not suitable for other uses.