mwm1752
Senior Member
- Location
- Aspen, Colo
Here I am getting more request to upgrade individual feeders in muti-dwelling units. Some instances are suggesting a service equipment upgrade. In general we are talking 1970's services with a main to a gutter tapping to feed the meter mains of each unit. Since the 70's it appears due to individual unit upgrades, the service conductors are not sized sufficiently to carry the load per 230.23, 230.31, & 230.42 (A).
Here is the conumdrum - my existing service conductors can handle 400 amps and have OCPD as a main disconnect rated at 400 amps which feed to such gutter & taps to some 15 units. The Building management wants to upgrade service equipment to say 800 amp rated main with meterstack assembly and fuse at 400 amps. This of course, open options to each dwelling for feeder replacement/upgrade/ load increase.
Though the existing condition have not cause over current tripping it leaves option for fuse replacement above the current carrying capacity of the service conductors if the fuses eventually start to open due to excess current draw. I keep landing on upgrade service comply with NEC 2014 230.23, 230.31, & 230.42 (A). Does anyone have a clear NEC code path otherwise in this type of situation?
Here is the conumdrum - my existing service conductors can handle 400 amps and have OCPD as a main disconnect rated at 400 amps which feed to such gutter & taps to some 15 units. The Building management wants to upgrade service equipment to say 800 amp rated main with meterstack assembly and fuse at 400 amps. This of course, open options to each dwelling for feeder replacement/upgrade/ load increase.
Though the existing condition have not cause over current tripping it leaves option for fuse replacement above the current carrying capacity of the service conductors if the fuses eventually start to open due to excess current draw. I keep landing on upgrade service comply with NEC 2014 230.23, 230.31, & 230.42 (A). Does anyone have a clear NEC code path otherwise in this type of situation?