winslowfam
Senior Member
- Location
- VA
Our client would like to tap his existing switchboard bus for a new feeder. The switchboard has no more space for additional feeder breakers. My reading of the Tap Rule makes it seem pretty straight forward for taps not more than 25 ft in length, but I wanted to put up this post to see if there is any other possible interpretation. My understanding is that the tap conductors' ampacity must not be less than 1/3 of the rating of the switchboard's main breaker, which is the overcurrent device protecting the feeder conductors (main bus of this switchboard). The problem we are having is that the main breaker is rated 4000A, so any tap we install will require over 1300A of wire...more than we need for our new load.