AIC rating of panel versus panel main breaker

[LUIS FERNANDEZ]

We have a job that the fault cuttent at the panel is 5600 Aic but the main breaker which is a 150A has to be rated 22,000 for coordination purposes, does the panel bus itself has to be rated 22,000 or it could be 14,000.

 

[ron]

The bus within the panel has to withstand the fault current imposed .. 5600A.

 

[jim dungar]

We have a job that the fault cuttent at the panel is 5600 Aic but the main breaker which is a 150A has to be rated 22,000 for coordination purposes, does the panel bus itself has to be rated 22,000 or it could be 14,000.

The breakers in the panel need to be rated for 5,600 AIC minimum, anything beyond that is acceptable. The bus bars of the panel also just need their SCCR to be above the available fault current.

Normally, but not always, the AIC rating of a device does not affect its ability to be coordinated. However there times, like when a different model breaker is needed.

The circuit X/R ratio also affects the application of protective devices, so I like to leave a 20% margin, when choosing the AIC rating of a breaker based only on available SCA.