AIC Rated

[Mike83]

I have 2 200 amp main breaker panels in a medical building that are rated for 10k each and 2 200 amp non fused Disconnect that are rated for 10 k each. The inspector wants 22k AIC rating so my question is can i replace the disconnect breaker and leave the panels at 10k? The inspector is requisition amendment letter from the site engineer which in return he needs a letter from the power company which hasn't got back to yet. Try to figure out other Options before i start getting fine bye the GC

 

[mwm1752]

AIC rating is usually based upon conductor size, material, conduit type, & length from transformer -- All equipment requiring the 22k rating shall be rated 22k - if the panel board is rated 22k then changing out the breaker only is ok. 110.10

 

[gadfly56]

AIC rating is usually based upon conductor size, material, conduit type, & length from transformer -- All equipment requiring the 22k rating shall be rated 22k - if the panel board is rated 22k then changing out the breaker only is ok. 110.10

It isn't; it's rated for 10K.

 

[electrofelon]

It isn't; it's rated for 10K.

Just to be precise, a Panelboard does not have an AIC rating. The panel board may have a sccr, and the breakers have an AIC rating.

If these are main breaker panels, I would be surprised if the main breakers were only 10k

 

[Jraef]

Just to be precise, a Panelboard does not have an AIC rating. The panel board may have a sccr, and the breakers have an AIC rating.

If these are main breaker panels, I would be surprised if the main breakers were only 10k

Agreed. Most 200A panels are rated at a minimum of 22kA withstand (now called SCCR), usually higher. It's the breaker that has the IC rating. Contact the panel mfr for help. The 10kA down stream branch breakers may be "series listed" with the main for 22kA total, but they may not, which would require changing all of the branch breakers too. The mfr can tell you, but be wary of distributors who may have an agenda to sell you all new equipment. Get the answers from the horse's mouth.

Your non-fused disconnects will be a bigger problem, non fused are almost never rated more than 10 kA SCCR, it's the fuses that protect it from anything higher. You may have to change them to Fused Disconnects. And no, you can't just add fuses even though technically it would be the same, because the AHJ is going to want to see a label or documentation of it as a complete device with at least 22kAIC. A reoprt from a PE might suffice, but just buying fused disconnects might be cheaper anyway.

 

[templdl]

I have 2 200 amp main breaker panels in a medical building that are rated for 10k each and 2 200 amp non fused Disconnect that are rated for 10 k each. The inspector wants 22k AIC rating so my question is can i replace the disconnect breaker and leave the panels at 10k? The inspector is requisition amendment letter from the site engineer which in return he needs a letter from the power company which hasn't got back to yet. Try to figure out other Options before i start getting fine bye the GC

What is the inspector's request based upon? From what I can tell it's because he said so. Or, what he customarily has seen in similar facilitiesin the area. Not good enough.
Ask you POCO first. If not, plan B is to identify the KVA of the transformer which feeds your facility to determine we ith a we ordered posible case sinerio using an unlimited fault current available from you POCO and a 100% motor contribution.
If that figure exceeds 10ka then start fine tuning the results with a fault systems study done by a PE who has experience to do how much dodo you are in. They have the wherewithal to do any calculations that are necessaru to determine the actual available fault current at the secondary of you transformer as well as all the conductor and other components rhat may contribute to the system nimpedance to reduce the available fault current as well as any devices that my contribute to it.
If you do discover a problem you may want to consider if any of the over current protective devices can be series rated with an upstream overcurrent protective device that will allow those down stream devices to be series rated.
You have to first with the facts and not because he said so. You may very well have an issue. But, if you have to make adjustments it would be prudent to do and upgrade as cost effectively as possible.

 

[petersonra]

I have 2 200 amp main breaker panels in a medical building that are rated for 10k each and 2 200 amp non fused Disconnect that are rated for 10 k each. The inspector wants 22k AIC rating so my question is can i replace the disconnect breaker and leave the panels at 10k? The inspector is requisition amendment letter from the site engineer which in return he needs a letter from the power company which hasn't got back to yet. Try to figure out other Options before i start getting fine bye the GC

The required AIC rating is not based on what the inspector "wants". It is based on the available short circuit current at the device. What is the available short circuit current?

It might be above 22kA. if so, what the inspector wants is not adequate to meet code.

 

[Jraef]

In my experience, questioning the motives of an AHJ is kind of like walking into a biker bar and saying you think guys wearing leather are all gay. You might be right, but that doesn't mean your not going to get hurt by saying it out loud...

 

[mwm1752]

In my experience, questioning the motives of an AHJ is kind of like walking into a biker bar and saying you think guys wearing leather are all gay. You might be right, but that doesn't mean your not going to get hurt by saying it out loud...

Kinda a odd comment coming from a moderator (people are influenced by you in your position), maybe its how you responded to AHJ issues (and yes I've dealt with real jerk AHJ's)
-- Its better to ask and learn or figure out the reasoning -- never stick your head in the sand -- you can pick your battles afterward --

 

[templdl]

Kinda a odd comment coming from a moderator (people are influenced by you in your position), maybe its how you responded to AHJ issues (and yes I've dealt with real jerk AHJ's)
-- Its better to ask and learn or figure out the reasoning -- never stick your head in the sand -- you can pick your battles afterward --

Oh Oh.

 

[Jraef]

Kinda a odd comment coming from a moderator (people are influenced by you in your position), maybe its how you responded to AHJ issues (and yes I've dealt with real jerk AHJ's)
-- Its better to ask and learn or figure out the reasoning -- never stick your head in the sand -- you can pick your battles afterward --

Well, we don't KNOW that the inspector only wanted it, for all we know the inspector was doing his job, because he KNEW the AFC was more than 10kA. So I think it's safer to assume that rather than question him.

ASKING him, respectfully, might be an alternative if you are relatively sure the AFC is under 10kA. But given the nature of the question from the OP, I doubt he has that level of confidence and approaching an AHJ to demand their reasoning for a request is, in my experience, the opening salvo in a battle. That battle might end up being one you win, but in a war you will ultimately lose. In my experience a hostile AHJ can make a job a money loser really fast if they have a mind to it.

 

[bsmith8691]

On the inside cover of the panel there should be the information needed. It should tell you if the panel is series rated and at what AIC.

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