This could possibly be a UL, Safety, or engineering quetsion but I'll go here.
I couldn't find much using search, my key words: tap, bus, and, bar were too common.
Anyway we have a 12,750 - 277/480 xfmr (not sure of the rating yet) supplying switchgear with a 1200A main, and 6 400/3 switches. 6 switches is all the space the gear has. The facility is requesting an additional service of 400A. The facility electrician has told them we can tap the bus and hang a 400/3 disconnect on the end of the gear. The panel is lightly loaded approx 25% and working clearance would not be an issue. I don't like this idea and feel like its a sub par installation, but I can't find a reason to say we can't do it. I am getting a lot of pressure to "make it work." What do you think?
I couldn't find much using search, my key words: tap, bus, and, bar were too common.
Anyway we have a 12,750 - 277/480 xfmr (not sure of the rating yet) supplying switchgear with a 1200A main, and 6 400/3 switches. 6 switches is all the space the gear has. The facility is requesting an additional service of 400A. The facility electrician has told them we can tap the bus and hang a 400/3 disconnect on the end of the gear. The panel is lightly loaded approx 25% and working clearance would not be an issue. I don't like this idea and feel like its a sub par installation, but I can't find a reason to say we can't do it. I am getting a lot of pressure to "make it work." What do you think?