We are designing some 12,470VAC distribution for a primary metered customer - so NEC 2017 applies. We are designing bollards around some outdoor oil-filled transformers. We have the local utility standards as a reference, but we obviously need an NEC compliant (and more importantly SAFE design). Our transformers are dead front, with 15kV 200A load break elbows - shotgun work. They also have bay-o-net fusing - more shotgun work.
We do need some bollards about the transformers. The utility standards require a 5' minimum clearance along the door radius, but they allow bollards up near the side of the transformer.
110.31(D) requires "suitable guards" - so the bollards will be included in the design
250.194(A) requires metal "fences" within 16 feet of exposed electrical conductors to be bonded
Here are my questions:
1. Are these "dead front" transformers considered, uhh, dead fronts? In other words - when the elbows are pulled do we treat it as if there are no exposed conductors?
2. If bollards are within 16 feet of the transformer, and include a metallic pipe, should they be bonded?
Thanks!
We do need some bollards about the transformers. The utility standards require a 5' minimum clearance along the door radius, but they allow bollards up near the side of the transformer.
110.31(D) requires "suitable guards" - so the bollards will be included in the design
250.194(A) requires metal "fences" within 16 feet of exposed electrical conductors to be bonded
Here are my questions:
1. Are these "dead front" transformers considered, uhh, dead fronts? In other words - when the elbows are pulled do we treat it as if there are no exposed conductors?
2. If bollards are within 16 feet of the transformer, and include a metallic pipe, should they be bonded?
Thanks!