How to determine the SMA Inverter's exact Breaker KAIC value when installed on a combiner box.

[electrofelon]

The document is poorly written. It's not really clear what "65kaic" means for the combiner. I think we deduce that that is the rating of the main breaker. It's not clear if the 42 and 25 kaoc breakers are acceptable without knowing the AFC at that point or if they have a series rating.

 

[inforaj]

The document is poorly written. It's not really clear what "65kaic" means for the combiner. I think we deduce that that is the rating of the main breaker. It's not clear if the 42 and 25 kaoc breakers are acceptable without knowing the AFC at that point or if they have a series rating.

Panel boards are typically rated based on the lowest AIC of any installed device.
Just specify the minimum Short Circuit Current Rating (SCCR) you want for the panel and let the contractor or manufacturer supply appropriately rated equipment.

The single-line mentioned above is typically supplied by contractors. We must confirm these specifications. I am very knowledgeable about building specifications, but since solar power is backfeed to the utility, I am becoming a little perplexed about this. Additionally, the manufacturer needs the accurate value rather than performing any calculations in order to get the right size.

Below are the snapshot for Eaton Breaker specs. I just want to know how to calculate and verify these values.

 

[electrofelon]

The single-line mentioned above is typically supplied by contractors. We must confirm these specifications. I am very knowledgeable about building specifications, but since solar power is backfeed to the utility, I am becoming a little perplexed about this. Additionally, the manufacturer needs the accurate value rather than performing any calculations in order to get the right size.

Below are the snapshot for Eaton Breaker specs. I just want to know how to calculate and verify these values.
View attachment 2563762

Someone needs to find out the AFC. Seems like there is just lots of guessing or assuming based on the existing equipment. Without a AFC value everything is just guess work.

 

[ggunn]

Someone needs to find out the AFC. Seems like there is just lots of guessing or assuming based on the existing equipment. Without a AFC value everything is just guess work.

Agreed. If you can't determine the AFC at the point where the panel or switch is to be installed, just use the AFC at the transformer. It will be overkill but it will be safe.

 

[inforaj]

Agreed. If you can't determine the AFC at the point where the panel or switch is to be installed, just use the AFC at the transformer. It will be overkill but it will be safe.

This will be helpful—the base we may assume for the transformer AFC.