duct bank
- Thread starter mswartho
- Start date
- Status
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Re: duct bank
NEC 300.3(B): All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors and bonding conductors shall be contained within the same raceway, auxiliary gutter, cable tray, cablebus assembly, trench, cable, or cord, unless otherwise permitted in accordance with 300.3(B)(1) through (4).
The installation you describe does not meet any of the next four paragraphs, so it would be a code violation.
The size of the equipment grounding conductor is based on the overcurrent protection device. You didn?t give us that detail. There is also the difficulty that no NEC table gives an ampacity for a set of three single insulated 1250 mcm, 15kV conductors in conduit. The closest I found was Table 310.69, but it applies in free air, and not conduit. Once you have selected the OCPD setting, go to Table 250.122 for the EGC size.
NEC 300.3(B): All conductors of the same circuit and, where used, the grounded conductor and all equipment grounding conductors and bonding conductors shall be contained within the same raceway, auxiliary gutter, cable tray, cablebus assembly, trench, cable, or cord, unless otherwise permitted in accordance with 300.3(B)(1) through (4).
The installation you describe does not meet any of the next four paragraphs, so it would be a code violation.
The size of the equipment grounding conductor is based on the overcurrent protection device. You didn?t give us that detail. There is also the difficulty that no NEC table gives an ampacity for a set of three single insulated 1250 mcm, 15kV conductors in conduit. The closest I found was Table 310.69, but it applies in free air, and not conduit. Once you have selected the OCPD setting, go to Table 250.122 for the EGC size.
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