Tachyon2
Member
- Location
- San Francisco
- Occupation
- Electrician
I have a 45kva 208/120v to 480v 3ø - reverse wired - Delta/Wye transformer grounded to a steel colum with #2str .Primary Conductors: 3/0 with a fused 200A OCPD next to it, that is supplied by a 200A, 65k breaker within the main electrical room 30 ft away. (120/208v 225A PRL1 withbreaker Subfeed )
The 45kva transformer secondary is supplying a 40a fused' 100A 600v rated disconnect that is within 5' feet of the txrm. Then the circuit pipes up 110 ft up an Elevator hoistway to feed one more '40A ( 100A 600v fused rated Disconnect.) Then 15' to the NEW elevator controller No conductors are landed as yet. ( FLA 25A / 6.5 HP )
My thought is there might have been a larger Xtrm in place of the 45k in the past. 75KVA? Also they must have sized conductors to 250% (NEC 450.3(b) in mind.
My questions are:
What do I need to change out to brings this setup code compliant as it will be soon be combed over by the AHJ,
What can I leave in place?
IE : drop my Trxm primary breaker size and feeder size, primary fuse size/ hoistway conductor size?
One last detail, there is #1 thhn leaving the Secondary OCPD, running to the rooftop mechanical rm's service OCDP. Unknown why it's so oversized. I assume this is too large to clear a fault to the xtrm's adjacent secondary OCPD
Thanks for the help!
The 45kva transformer secondary is supplying a 40a fused' 100A 600v rated disconnect that is within 5' feet of the txrm. Then the circuit pipes up 110 ft up an Elevator hoistway to feed one more '40A ( 100A 600v fused rated Disconnect.) Then 15' to the NEW elevator controller No conductors are landed as yet. ( FLA 25A / 6.5 HP )
My thought is there might have been a larger Xtrm in place of the 45k in the past. 75KVA? Also they must have sized conductors to 250% (NEC 450.3(b) in mind.
My questions are:
What do I need to change out to brings this setup code compliant as it will be soon be combed over by the AHJ,
What can I leave in place?
IE : drop my Trxm primary breaker size and feeder size, primary fuse size/ hoistway conductor size?
One last detail, there is #1 thhn leaving the Secondary OCPD, running to the rooftop mechanical rm's service OCDP. Unknown why it's so oversized. I assume this is too large to clear a fault to the xtrm's adjacent secondary OCPD
Thanks for the help!
