kaic ratings and selctive coordination

[bccodes]

In reveiwing a set of plans for a 5 story building I have come across the following dilemma
Local power company sez we need 100,000 amp interrupting capacity
The MDP is rated at 65KAIC.
The panels downstream of it are rated at 10KAIC
The specs say breakers are to be 14KAIC
The building will have a Standby Gen. due to the need for a Fire Pump and Accessable Elevator,hence selective coordination applies (Article 701)
It seems to me that a short on a branch circuit could damage the breaker and associated panel and not properly clear until the MDP opens or something downstream of it blows up or catches fire.This also just wrecks any thoughts of selective coordination like the fire pump working to put out the fire that probably just hapenned.
Am I on the right track here?????

 

[ron]

Never mind coordination, the protective devices need to be rated to handle the available fault current. Then you can make sure there is selective coordination in the generator distribution to the loads.

 

[bccodes]

bccodes

bccodes

Thanks Ron,
Does this mean that all breakers and panelboards need to be rated at 100K??

 

[augie47]

ratings

ratings

bccodes: check your message box

 

[jim dungar]

Thanks Ron,
Does this mean that all breakers and panelboards need to be rated at 100K??

The breakers need to be rated (series or fully ) for the fault current available at their line terminals. Different locations in the electrical system will have different fault levels due to the amont of impedance between them and the service entrance. A short circuit study will determine the different fault current levels.

 

[kingpb]

You may want to consider installing current limiting reactors between the transformer load terminals and the switchgear main. Since its a high rise, voltage regulation should not be a problem and be fairly steady. You can improve the voltage by tapping the transformer accordingly.