-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I'm rethinking our assumptions from earlier this year, and we need to settle on this soon. We need to make sure we're choosing the *most useful* configuration for power in the SSF. Nothing we choose will be universally applicable, but as long as we come up with something that's going to be the trend, we can buy the right PDUs to make it useful to whatever going into the cabinets. What concerns me is that the trend in the computing clusters I see coming in is definitely skewing to the 60A range and not in the 30A range -- this is precisely what prompted our discussion in the meeting on Friday about converting to 60A. Should we be looking at going with a 60A 3 Phase run to every cabinet, alternating UPS and non-UPS for each receptacle? Should we further adopt a hybrid strategy, wherein we deploy 4 x single phase 208 to ALCF's area, 2 x 30A 3 phase to a portion of the room, and 60A 3 phase to another portion? It's starting to feel like the latter is the right choice. Incidentally, the proposed (by Teng) SSF PDU schematic and data sheet is now the wiki: http://wiki.mcs.anl.gov/SSF/index.php/Image:PDM_Mk_II.pdf http://wiki.mcs.anl.gov/SSF/index.php/Image:PDM-MK-II-Schematic.pdf == Craig On Sep 29, 2008, at 1:40 PM, Schmitz Corby wrote:

The wiring would need to change. #10 stranded will be too small and, we should check with Paul, but I believe that using parallel conductors is not allowed with smaller than a #2. We would have to consult the tables, but this would be a #4 I believe. There is another consideration here, the standard conduit size for a 5 wire 3- phase circuit is 3/4" (squeezing it into a 1/2" is not advisable). We would need at least a 1-1/2" conduit for 5x #4 conductors to support the 60a circuits. I am not sure what we are planning as far as electrical distribution, but it is something that we should hash out as it drives the maximum size of circuits going out to our cabinets.

-corby

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