AIC Ratings

[Designer101]

Is the reviewer asking for the solar breaker to also have a 22kA series rating with the branch breakers like the main does?

yes, his wording is" if service interrupt is rated 22KA, The new breaker should be rated for the same value".

 

[petersonra]

yes, his wording is" if service interrupt is rated 22KA, The new breaker should be rated for the same value".

why would the rating matter? it is about the available short circuit current.

 

[electrofelon]

why would the rating matter? it is about the available short circuit current.

As I said before, probably an assumption that the 22k was properly selected. I'm not saying it's correct, but it's a common approach.

 

[jim dungar]

yes, his wording is" if service interrupt is rated 22KA, The new breaker should be rated for the same value".

The reviewer is probably taking the path of least resistance.

Per 110.09 a protective device needs to be rated for the available fault on its line side.
In your case you should be able to use a series rating for when the solar breaker is being fed by the utility. The solar breaker also needs to be rated for the fault current provide by the PV system. You would need to provide documentation that shows the PV provides less fault current than the breaker you are suggesting.

 

[petersonra]

The reviewer is probably taking the path of least resistance.

Per 110.09 a protective device needs to be rated for the available fault on its line side.
In your case you should be able to use a series rating for when the solar breaker is being fed by the utility. The solar breaker also needs to be rated for the fault current provide by the PV system. You would need to provide documentation that shows the PV provides less fault current than the breaker you are suggesting.

If the solar breaker is a backfed breaker, and the available short circuit current from the solar exceeded 10 kA, would the other breakers need to be 22 kAIC as well?

 

[jim dungar]

If the solar breaker is a backfed breaker, and the available short circuit current from the solar exceeded 10 kA, would the other breakers need to be 22 kAIC as well?

Not if the solar breaker was also series rated with the branches.

HOWEVER, I believe no series rating would be possible for the panel at all, if the solar backfed fault current exceeds 1% of the branch breaker non-series rated AIC (in this case 100A). My reasoning is similar to the limitation for motor loading found in 240.86(C). Luckily solar inverters are not usually very good at injecting fault current back into the POCO grid.

 

[WA_Sparky]

one question here in same topic
the main panel main breaker is rated for 22KAIC,400A main panel Eaton.
usually KAIC RATING LISTED IN eaton BR breakers are 10kAIC
Now the plan reviewer wants us to revise the plans to show eaton BR breaker to be rated 22kaic as well For the solar breaker 40A.

so as per the above discussion the breaker itself is rated for 600 volts, means 240 volts should be rated for up to 65 KAIC?
What's the calculation involved here, can somebody please help me understand this. so I can convince plan reviewer.

If i have it correct, you would have had to actually specify the correct BR breaker model number to achieve 22KAIC protection. The BR breaker is only intended for (1) voltage range, 120/240V.