service entrace tap

[bradleymattlin]

I have 3 sets of 3/0 copper parallel feeders coming in from a CT cabinet, thru a trough and into a 400 amp distribution panel. My tap is for 100 amps and using number 1 copper and going to tap off one leg of A phase and one leg of B phase and a neutral to give my 120/208. My tap is under 10 feet and all rules apply for 240.21. Can someone explain to how the 3/0 copper that iam tapping into doesn't have to be bigger and handle the load of the new tap, or maybe it doesn't work that way and its just voltage. Thanks

 

[infinity]

According to the tap rules and Article 100 definitions this is not a tap since these are service entrance conductors and do not have an OCPD ahead of them.

 

[curt swartz]

You are planning to just connect into one of the sets of parallel conductors? If so that would not be code compliant. Each set of parallel conductors are required to be exactly the same so the load is distributed equally across all of them. You would need to either connect you new conductors to either end where the parallel conductors come together or install a 7 port distribution block in the middle of the run.

 

[texie]

I have 3 sets of 3/0 copper parallel feeders coming in from a CT cabinet, thru a trough and into a 400 amp distribution panel. My tap is for 100 amps and using number 1 copper and going to tap off one leg of A phase and one leg of B phase and a neutral to give my 120/208. My tap is under 10 feet and all rules apply for 240.21. Can someone explain to how the 3/0 copper that iam tapping into doesn't have to be bigger and handle the load of the new tap, or maybe it doesn't work that way and its just voltage. Thanks

As some might say, I think we have a failure to communicate.
If you are connect directly in the CT cabinet to lugs that are in addition to the lugs for the other service conductors this is not a tap as Infinity said. They are simply service conductors and all is well as long as you don't exceed the ampacity of the CT cabinet with your calculated load.
If on the other hand you are doing as Curt said and connecting to the existing parallel conductors for this, then this would not be compliant.