What are your thoughts and experiences, the good, the bad and the ugly, of manufactured electrical building systems. The ones that come with equipment installed and pre-wired ...
My new projects are generally grassroots at 480V with plenty of MCC lineups.
Note that there are competing alternatives using building spaces (office/garage/warehouse) that can be used for installing the electrical equipment.
I put in a good number of them, full with LV and MV switchegars, MCC's and MV staters, raised floor DCS rackrooms, etc.
No roof entry or penetration to prevent leaks. (When it is large enough so that you have to ship them in sections watch out how the seam is done.)
My requirements are call for elevated buildings, put them on 4/6 columns and have the distribution transformers underneath.
N+1 wall mounted HVAC units with centralized control, integrated fire detection and alarm. Keep it slightly pressurized to keep dust out.
Cable tray distribution.
Building fabricators like to use wireways at the top perimeters and throw all the wiring there. I don't allow this but ask them to use a perimeter tray to make additions and interwiring more flexible. (Have you unbolted 60' wireway to add a circuit?)
Pay attention to the paintjob quality and patch up after placement. (UV protection is a must in the spec. We have a building that is 'chalking'.) Precoated panels, folded panels seals, how continuity of the coating is assured of the precoated panels after fabrication, etc. Ask lot of questions....
Allow for equipment removal by oversized doors or removable panels.
Watch out for the panel construction, minimum gauge size for rigidity, support member locations in the wall where you can field-mount additional equipment. Floor loading and penetration locations, load bearing reinforcment where heavy equipment may be located, like battery racks.
Provide cable transits for all - including future - wire penetrations through the walls and floor. (It is difficult to add more in the future.)
