[watersparkfalls]

howdy folks,
I have a job i am looking at and wanted a second opinion.
a warehouse is adding some indoor offices by loading docks, which will be used for typical office stuff(computers, printers,lights, ect... oh and a break room with microwave) they have a 480/277 panel which feeds a 45 kva (60 amps input 125 amps output)transformer which feeds a 208/120 panel that has no space left for any more breakers(loads are 98% 1 pole 20 amp with 1 3phase conveyor belt @ 20 amps and a 2pole 30amp recep) I am thinking of adding sub panel from existing panel and junction conveyor circuit in existing panel and re feed from my new sub panel along with new offices.
Does this seem logical or would double barrel lugs on x1,x2,x3 make more sense skipping the juntion part in existing panel? I like the junction part so I dont have to shut transformer down along with everything in the panel too.

What would you do is my question? Thanks,
H2O

 

[BryanMD]

480/277 panel which feeds a 45 kva transformer
which feeds a 208/120 panel that has no space left

Amp load and balance is the issue.
The rest of your post sounds like you have a handle on things.

Assuming the existing load leaves room to add the new work it doesn't matter a lot (electrically) where you get the power from. In the real world, adding a sub panel off the 208/120 with an X amp breaker would be the simplest (no or minimal shut down) approach.