adalewhite
Master Electrician, Electrical Design, Veteran
- Location
- Georgia
- Occupation
- Licensed Electrician, Electrical Designer, A&E PM
I am reviewing the proposed installation below on a renovation project where a new 125A MLO Panel for guest room fan coil units is being installed ajacent to an existing 225A MLO.
"COMBINE NEW FEEDERS(PARALLEL) FOR PANELS C AND C2,AND A AND A2 IN EXISTING 2-1/2" CONDUIT WITH 4#1/0 + 4#2/0 +1#4G"
Looking in the NEC this is not really "parallel" feeders as recognized by the NEC since they are serving different loads and are different lengths. Conduit fill is OK, cunductors will have to be derated for more than three. The smaller feeder will pass through the existing panelboard cabinet so 40% fill will have to be reviewed for the cross section the conductors pass through the can. A warning label for the feed through conductors per 312.8.
I do not see any code issue right off that would prevent this solution to a difficult conduit route in an existing building but just do not see it as a good practice. The client's engineering standards for this location does not even allow combining more than three circuits in a homerun "(8) Maximum of three phases or poles shall be installed in any conduit system, which includes single-phase circuits, regardless of derating tables in the NEC."
Does anyone know anythign that would preclude this suggestion?
Thanks in advance.
I am BlessedToBeFree!
"COMBINE NEW FEEDERS(PARALLEL) FOR PANELS C AND C2,AND A AND A2 IN EXISTING 2-1/2" CONDUIT WITH 4#1/0 + 4#2/0 +1#4G"
Looking in the NEC this is not really "parallel" feeders as recognized by the NEC since they are serving different loads and are different lengths. Conduit fill is OK, cunductors will have to be derated for more than three. The smaller feeder will pass through the existing panelboard cabinet so 40% fill will have to be reviewed for the cross section the conductors pass through the can. A warning label for the feed through conductors per 312.8.
I do not see any code issue right off that would prevent this solution to a difficult conduit route in an existing building but just do not see it as a good practice. The client's engineering standards for this location does not even allow combining more than three circuits in a homerun "(8) Maximum of three phases or poles shall be installed in any conduit system, which includes single-phase circuits, regardless of derating tables in the NEC."
Does anyone know anythign that would preclude this suggestion?
Thanks in advance.
I am BlessedToBeFree!
