I have this project where I have a 500kVA, 13.8kV-220/127V, delta-wye distribution transformer, which is serving a 1600A switchboard. My secondary feeder (from transformer to the switchboard) has 4 parallel sets of #600KCMIL copper in a PVC conduit. In total, I have 4 PVC conduits and each conduit has 3 hots, 1 neutral, and the supply-side bonding jumper (SSBJ). It confuses me about the sizing of the SSBJ.
From the 2011 NEC Art. 250.30(A)(2)(a)(b), the size of the SSBJ for parallel conductor installations shall be according to Art. 250.102(C)(2). The confusing part is the term single-supply-side bonding jumper (SSSBJ), which shall be sized according to Art. 250.102(C)(1).
Is the SSSBJ will be installed/run in each PVC conduit with the hots and neutral conductors? If so, the size of my SSSBJ in each conduit will be the 12.5% of the total sum of ungrounded conductors, which is #300KCMIL, if larger than 1100KCMIL. How it will be install? OR, the size of the SSBJ in each conduit will be according to Table 250.66, which will be #1/0AWG in each PVC conduit for each set of parallel installation.
This explanation from the 2011 NEC Art. 250.102 Handbook confuses me even more, "From an installation standpoint, it is likely that installing the five smaller supply-side bonding jumpers (one to each conduit) will facilitate proper bonding of the raceways when compared to installing a single, 250kcmil conductor through the five fittings that are used to connect the bonding jumper to the rigid metal conduits."
Can anyone clear this up for me? Thank you.
From the 2011 NEC Art. 250.30(A)(2)(a)(b), the size of the SSBJ for parallel conductor installations shall be according to Art. 250.102(C)(2). The confusing part is the term single-supply-side bonding jumper (SSSBJ), which shall be sized according to Art. 250.102(C)(1).
Is the SSSBJ will be installed/run in each PVC conduit with the hots and neutral conductors? If so, the size of my SSSBJ in each conduit will be the 12.5% of the total sum of ungrounded conductors, which is #300KCMIL, if larger than 1100KCMIL. How it will be install? OR, the size of the SSBJ in each conduit will be according to Table 250.66, which will be #1/0AWG in each PVC conduit for each set of parallel installation.
This explanation from the 2011 NEC Art. 250.102 Handbook confuses me even more, "From an installation standpoint, it is likely that installing the five smaller supply-side bonding jumpers (one to each conduit) will facilitate proper bonding of the raceways when compared to installing a single, 250kcmil conductor through the five fittings that are used to connect the bonding jumper to the rigid metal conduits."
Can anyone clear this up for me? Thank you.
