USACE_Nash
Member
- Location
- Nashville, TN
Hello all,
I am currently working on rehabbing shore power power distribution on a non-floating pier for some large vessels, like commercial tugs and a dredging barges. I have a total of six 480 V three phase shore power stations, five 100 A and one 200 A for the dredge.
I have been trying to apply Article 555 but I am starting to wonder if that is correct for industrial style shipyard applications. In the 2017 version there is a requirement for 30 mA ground-fault protection and I'm not sure how you would accomplish that for a 200 A, 480 V circuit. And I saw today that the 2020 version has a limit of 250 V between phases, which makes me think that this article is really only intended for smaller craft. I'm pretty sure really large vessels like cruise ships and super tankers take all the way up to 13.8 kV, so where would one find the appropriate code? I wouldn't think it would be the NESC as these circuits are still going to end up as branch circuits off of the main panel at the yard.
Also, the pier construction is a concrete shell with a rock/earth fill. The circuits will be buried in the earthen portion and run to power stations located at the edge on the concrete. The surface isn't that far above water and I've been told that the ground water level in the earthen center portion is pretty much the same level as the water surrounding the pier so the conduit is probably going to spend a fair amount of time in saturated ground. Does anyone have any recommendations or tips other than calling out PGRS?
I am currently working on rehabbing shore power power distribution on a non-floating pier for some large vessels, like commercial tugs and a dredging barges. I have a total of six 480 V three phase shore power stations, five 100 A and one 200 A for the dredge.
I have been trying to apply Article 555 but I am starting to wonder if that is correct for industrial style shipyard applications. In the 2017 version there is a requirement for 30 mA ground-fault protection and I'm not sure how you would accomplish that for a 200 A, 480 V circuit. And I saw today that the 2020 version has a limit of 250 V between phases, which makes me think that this article is really only intended for smaller craft. I'm pretty sure really large vessels like cruise ships and super tankers take all the way up to 13.8 kV, so where would one find the appropriate code? I wouldn't think it would be the NESC as these circuits are still going to end up as branch circuits off of the main panel at the yard.
Also, the pier construction is a concrete shell with a rock/earth fill. The circuits will be buried in the earthen portion and run to power stations located at the edge on the concrete. The surface isn't that far above water and I've been told that the ground water level in the earthen center portion is pretty much the same level as the water surrounding the pier so the conduit is probably going to spend a fair amount of time in saturated ground. Does anyone have any recommendations or tips other than calling out PGRS?