AIC ratings

[Davebones]

Have a new panel with a main breaker ( 480V 3 Phase 250 Amp ) . The panel has a AIC rating of 100,000 amps with a main breaker installed . Now the branch breakers are rated 14,000 amps . Can you install this on a system that has 32,000 amps of available fault current .This is on a series rated system ....

 

[jim dungar]

Does the panel have a lable that says it is 'series rated' using these devices, see NEC 110-22.

 

[LEO2854]

Also look at 240.86

 

[Davebones]

Its a Siemens that has a chart showing this combination.

 

[jim dungar]

Its a Siemens that has a chart showing this combination.

Then it meets the NEC and UL.
Do your project specifications allow series rated equipment?

 

[kingpb]

Then it meets the NEC and UL.
Do your project specifications allow series rated equipment?

Good point to mention, because my specs do not allow it.

 

[Davebones]

No specs as this was added to a existing manufacturing plant a few years back. Saw where there seems to be be more information out there about the AIC rating of equipment . I know a contractor added this and no engineering was done . As I wrote before this is a Siemens and the label says 100,000 aic with main breaker installed . Just trying to better understand the AIC of this equipment and the proper way to install . We are going to get a Arc Flash study done on the electrical equipment in the plant to verify our equipment is properly rated . Over the years theres been numerous changes to the electrical system by outside contractors .......

 

[Jraef]

OK so the deal is, the panel and the breakers used in it CAN have a Series Combination Rating that might exceed the rating of some of the individual components if they were standing alone. In essence, the panel in combination with ALL of the devices in it is acting as a whole unit to safely interrupt faults that might otherwise damage lower rated units. But this applies to very narrowly specific tested combinations of devices, NO DEVIATIONS. You have to make sure the devices in your panel are ALL listed, by Siemens, to be used in the combination that allows the higher rating. You cannot make any assumptions on your own or in the field.

Here is where you can download the Series Combination Ratings for Siemens breakers:
Residential (240V max in load centers and small panelboards):
Industrial (600V max in panelboards and switchgear): This one is a little funky because the only thing I could find was the actual printing file for the cards that they would put into the panelboards themselves, so every other one is upside down.

 

[Davebones]

Thanks to everyone for the information....I appreciate it very much...