Built 120V circuits, now need single phase 208V circuits 1

[hawaiianhokie]

Hi,
Last year we had a 100amp panel (2 hots) in our server room. It gets its power from the main panel, which is a 3 phase panel, 100 amps per leg. I ran 5 120V 20amp circuts from the server room panel. We run 120V servers from these, or, we did...

Now we're switching to single phase 208V chassis, and I need to have our server room power changed to single phase 208V circuits. I only need to support four chassis, and I can get rid of all five of the 120V circuits. The chassis are supposed to draw 4000watts each, at 208V single phase.

Is there any reason why I can't make four 20amp, 208V circuits from the same 100 amp panel? Of course these will be completely new circuits.

Thanks

 

[SierraJ]

If all the information you provided is correct (the main panel is three phase, the server room panel is 120/208 with two "hots" & one neutral) then you can install new 208V branch circuits to feed the new server from this server room panel.

However you need to take make sure that the system has enough capacity to handle the new load, i.e.

1.) 5 circuits x 20A@120V = 5 x 2400 = 12,000 VA

2.) 4 circuits x 20A@208V = 4 x 4160 = 16,640 VA

As you can see, although your 100A server room panel is adequate to feed the new servers, in theory the main panel will need to supply an additional load of 4,640VA.

 

[hawaiianhokie]

Thanks,
I was wondering what I was missing, and it was the volt/amp calculation. Looks like I will have just enough power available at the main panel for this year.

Now, can you install a new 600amp main panel for me =^)