Temp Power

A

Alwayslearningelec

Senior Member
Location
NJ
Occupation
Estimator
So GC wants 100A brought to each floor(4 floors- 4,5,6,7th floor) from 2nd floor. It's going directly up.

We don't know the calculated load so we are just provide 100A 120/208v panel on each floor

We are getting power for this riser from a 277/480v panel( not sure size but it has enough available power).

The plan is to run a feeder from 480v panel to 112kva xfrmr step down and run feeder to 400A panel( all this in same closet) then run (4) separate 100A MC cables to each floor 100A panel. Guess if sized correctly this makes sense?
 
I would realy just do..
2nd floor ceiling =2 holes
3rd floor ceiling =2 holes
4th floor ceiling =1 hole
5th floor ceiling =1 hole and so on..
And if we are doing cores for data, 4" and so forth, we kill 2 birds with one stone and just stuff them all in 1 hole....
Why not? No need to drill seperate holes on every floor, especially if its concrete.
Even if you re-purpose f/a holes... use them for temp. $$$$
Of course if you do this to save money and use cores you need in the future-
The holes need to be perfect...
 
rambojoe said:
I would realy just do..
2nd floor ceiling =2 holes
3rd floor ceiling =2 holes
4th floor ceiling =1 hole
5th floor ceiling =1 hole and so on..
And if we are doing cores for data, 4" and so forth, we kill 2 birds with one stone and just stuff them all in 1 hole....
Why not? No need to drill seperate holes on every floor, especially if its concrete.
Even if you re-purpose f/a holes... use them for temp. $$$$
Of course if you do this to save money and use cores you need in the future-
The holes need to be perfect...
Click to expand...
Ok so we do need to core drill. We're not doing data but we do have a lot of perm riser cores in those closets. I'm not following you, 2nd floor 2 holes etc. You mean multiple cable in one core? Also,I don;t think we could use the perm feeder riser cores for the temp as they would be needed so we'd have to make separate cores just for the temp( again, not doing data).
 
JoeStillman said:
Or just run a 400A riser from a secondary Sw/Fu at the transformer. Tap it with a MCB panel within 10' on each of the floors.
Click to expand...
Ok so 400A feeder up from secondary then tap box at each floor by 100A panel and run 100A feed over to panel...then reduce may be to 300A feeder going up to next floor and so on? Seems like more work then (4) 100A cables.
 
For the way I initially proposed would it make sense to do 3/0 cu from 480v panel to prim side xfrmr then 500 mcm from sec side xfrmr to 400A panel then AL MC cable from 400A panel to the 100A panels? Any reason not to do aluminum on prim and sec side of xfrms?
 
Alwayslearningelec said:
Ok so 400A feeder up from secondary then tap box at each floor by 100A panel and run 100A feed over to panel...then reduce may be to 300A feeder going up to next floor and so on? Seems like more work then (4) 100A cables.
Click to expand...
Reducing the feeder will be more expensive than going full size all the way. You need OCP @ the reduction.
 
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