AIC labeling

[mannyb]

we received a set of city approved drawings. the drawings dont have the AIC calculation on the drawings but the drawining does state that

ELECTRICAL CONTRACTOR SHALL BE RESPONSIBLE FOR THE PROVIDING AIC LABELING ON ALL ELECTRICAL DISTRIBUTION EQUIPMENT. AVAILABLE FAULT CURRENT LABELING IN LIEU OF THE MAXIMUM AVAILABLE FAULT CURRENT MARKING AS REQUIRED BY NEC ARTICLE 110.24 A PERMANENTLY AFFIXED LABEL SHALL BE APPLIED WITH THE FAULT CURRENT AT THE TIME OF THE INSTALLATION AND CALCULATION.

Now shouldnt the this already be on approved drawings before it gets approved ?? why would the engineer not provide on their drawings. why would the do all the A and E part of drawing then leave out the AIC ?

 

[tkb]

That would make my bid go up about 4K.

 

[Smart $]

... AVAILABLE FAULT CURRENT LABELING IN LIEU OF THE MAXIMUM AVAILABLE FAULT CURRENT MARKING AS REQUIRED BY NEC ARTICLE 110.24 ....
...

What the heck is that supposed to mean??? Sounds like they are openly instructing the contractor to violate the NEC... but available fault current and the maximum available fault current are the same, are they not? Or is it they are trying to say they have foreknowledge the POCO will change out the source to a higher AFC equipment at a later date and they're trying to sneak in some equipment that will not meet the required AIC at the later date???

 

[roger]

we received a set of city approved drawings. the drawings dont have the AIC calculation on the drawings but the drawining does state that

ELECTRICAL CONTRACTOR SHALL BE RESPONSIBLE FOR THE PROVIDING AIC LABELING ON ALL ELECTRICAL DISTRIBUTION EQUIPMENT. AVAILABLE FAULT CURRENT LABELING IN LIEU OF THE MAXIMUM AVAILABLE FAULT CURRENT MARKING AS REQUIRED BY NEC ARTICLE 110.24 A PERMANENTLY AFFIXED LABEL SHALL BE APPLIED WITH THE FAULT CURRENT AT THE TIME OF THE INSTALLATION AND CALCULATION.

Now shouldnt the this already be on approved drawings before it gets approved ?? why would the engineer not provide on their drawings. why would the do all the A and E part of drawing then leave out the AIC ?

Even though the comment states the EC is "RESPONSIBLE FOR THE PROVIDING AIC LABELING ON ALL ELECTRICAL DISTRIBUTION EQUIPMENT" it certainly does not imply the EC is responsible for the calculation(s), the engineer of record/designer would be responsible for that info, the EC would be responsible for the labeling.

Roger

 

[Smart $]

...
Now shouldnt the this already be on approved drawings before it gets approved ?? why would the engineer not provide on their drawings. why would the do all the A and E part of drawing then leave out the AIC ?

You'd think so on the first question. I can't answer the following questions. Sounds like something fishy is going on...:blink:

 

[dkidd]

See http://forums.mikeholt.com/showthread.php?t=134106

All to often, the information is not available from the utility at the design stage. Sometimes the only time to get a good conservative value is after the actual transformer has been installed.

 

[petersonra]

In a very legalistic way, an AIC rating only applies to OCPD like fuses and circuit breakers and they are generally marked at the factory. So this clause requires nothing at all.

Thes rest of it makes little sense.

 

[mgookin]

Is AIC really a calculation, or just a statement which affirms compliance?
The main OCPD has to withstand the AIC rating of the POCO supplying tranny. POCO tells you what the AIC rating of their equipment is and the EC or EE makes sure the main gear can withstand that rating.

I'd take that note to mean that at time of inspection you need to demonstrate to the inspector that you're in compliance. If the information was not available at the time the drawings were produced, it seems like the plans examiner let you defer it until such time it can be coordinated.
That being said, if it bites you at time of inspection, it's on the EC.

 

[Smart $]

Is AIC really a calculation, or just a statement which affirms compliance?

AIC rating is for "interrupting fault current" devices, which is supplied by the manufacturers because it is determined through testing. What the spec is referring to is the Available Fault Current, also known as the Maximum Available Fault Current (AFC or MAFC). See 110.24.

Regarding services, the only time calculation is involved is if you are wanting to use equipment with an AIC rating or SCCR lower than the AFC value provided by the POCO or as determined through calculation for other points in the premises distribution system.

 

[mannyb]

Even though the comment states the EC is "RESPONSIBLE FOR THE PROVIDING AIC LABELING ON ALL ELECTRICAL DISTRIBUTION EQUIPMENT" it certainly does not imply the EC is responsible for the calculation(s), the engineer of record/designer would be responsible for that info, the EC would be responsible for the labeling.

Roger

I take the statement to mean the same thing. all the EC contractor is responsible for is the actual placement of the calculation/