Confused about question for 200 amp service upgrade.

[wkeil]

http://imgur.com/HxoVhEr

I have read these forums alot and this is my first post. Im confused on the information the AHJ is requesting from me here in the above linked image. It is an image of the request. Any input is appreciated. I think I will call the utility and ask as well. Thank you.

Walt

 

[iwire]

You do need to call the power company.

The inspector is asking for the available fault current.

 

[JES2727]

Walt,

Call PSE&G Central Division at 1-800-782-0067. They'll put you in touch with the engineer for that area. They'll ask you for the address and the pole number.

 

[Dennis Alwon]

The utility here will only give the aic rating to the transformer. It will change depending on wire size, material , distance, etc into the building. THis you can do thru Mike Holt calculator- http://www.mikeholt.com/freestuff.php?id=shortcircuitcalculations or get an engineer

 

[kingpb]

First, AIC means Amps Interrupting Current

When the utility company gives you this number, make sure you ask them exactly where on the system this number applies.

If it is on the LV side of a distribution transformer that feeds the residence then compare it to the AIC or KAIC rating of the main breaker and panelboard. If the number they give you is lower than the breaker and panel rating then your done. However, if the number they give you is higher, then you will need to calculate the value at the panelboard. The calculated value at the panelboard will be lower due to the impedance in the cable. If the calculated number is still higher than the panel rating, than you have a problem.

 

[kwired]

If you know the KVA rating and impedance of the transformer you can calculate the "worst case" available fault current at the transformer terminals. Worst case meaning the calculation assumes an infinite available supply from the primary. The smaller the transformer - the more accurate this calculation becomes in reality as it will not have as much impact from primary limitations.