Hello. This is a little long; please bear with me:
An installation consists of a 750 kva dry type sub, 12.47 kV primary, 120/208 volt secondary. There is proper primary fusing at a 15 kV pad mounted switch outside the bldg. and a primary load break switch adjacent to the sub. (Primary is on owners system; the utility is way upstream). NOW: the secondary conductors run from the sub to a main dist. board with a 2500 amp bolted pressure switch main. The length of these conductors is less than 25 feet. During installation of the new sub and gear it was not possible to run separate conduits for the secondary conductors so the contractor routed them through existing large pullboxes at the ceiling of the room and then extended via wireway to the equipment. The contractor was told that if he routed these cables inside the junction boxes he would have to physically separate them from other feeder cables that are present in the box. Folks thought this could be done but it couldn't be. So is there a violation in having these conductors mixed with feeders per Art. 230.7? Or should this be viewed as a 25' transformer tap and Art. 240.21(B)(6) apply? If so, then would the last requirement that "the secondary conductors are suitably protected from physical damage" be satisfied by the fact that all conductors are in pullboxes etc.? The contractor is demanding that we show him where in the code he has done something wrong. He did not do what the drawings showed but it wasn't possible to do that.... We are concerned in that even if these are not service entrance conductors they do not have overcurrent at their source. The contractor did good work, bundled the cables and kept them as separate as possible.
A little disjointed description I know but that is the situation.
Thanks for your time. Have a Merry Christmas and 2004!
An installation consists of a 750 kva dry type sub, 12.47 kV primary, 120/208 volt secondary. There is proper primary fusing at a 15 kV pad mounted switch outside the bldg. and a primary load break switch adjacent to the sub. (Primary is on owners system; the utility is way upstream). NOW: the secondary conductors run from the sub to a main dist. board with a 2500 amp bolted pressure switch main. The length of these conductors is less than 25 feet. During installation of the new sub and gear it was not possible to run separate conduits for the secondary conductors so the contractor routed them through existing large pullboxes at the ceiling of the room and then extended via wireway to the equipment. The contractor was told that if he routed these cables inside the junction boxes he would have to physically separate them from other feeder cables that are present in the box. Folks thought this could be done but it couldn't be. So is there a violation in having these conductors mixed with feeders per Art. 230.7? Or should this be viewed as a 25' transformer tap and Art. 240.21(B)(6) apply? If so, then would the last requirement that "the secondary conductors are suitably protected from physical damage" be satisfied by the fact that all conductors are in pullboxes etc.? The contractor is demanding that we show him where in the code he has done something wrong. He did not do what the drawings showed but it wasn't possible to do that.... We are concerned in that even if these are not service entrance conductors they do not have overcurrent at their source. The contractor did good work, bundled the cables and kept them as separate as possible.
A little disjointed description I know but that is the situation.
Thanks for your time. Have a Merry Christmas and 2004!
