Mess: Power Wheeps and Extenders, something you should know

[BillP]

I recently opened a post asking for the possibility of cutting APC power wheeps (http://forums.apc.com/spaces/6/racks-rack-accessories-cooling/forums/general/2836/understanding-pdu-...), I anticipated what the below pictures show.

There's no way you can make room for so many connectors to feed rack PDUs, not in a regular canalization. PDMs have a flawed design, they should bring a guaranteed hardwire connection. After all If you feel the need to change or replace some PDM it would be a major pain to free the wheeps through the whole installation.

[BillP]

"come with breaker/whip moduels in various lengths"

This is not the case for 400v/230v configurations. PDPMs are all the same, what varies is the extender length (coming right of BOT).

Suppose in the future there where 400v/230V PDPMs with the desired lengths available without having to use extender wheeps,.. The whole point of a modular power distribution panel is being able to make changes, can you imagine removing one PDPMs 16Apms and replacing it by a 32Apms like the ones shown in the picture?

[upsguy_apc]

http://www.apc.com/products/family/index.cfm?id=431

The bottom of the list is all of the 400/230V breaker and whip modules with various lengths and current configurations from 140cm to 1080cm and you should be able to custom order 1680cm whips.

The number at the end of the part number is the length of the whip in CM.

Here is a PDPM that is unpopulated and you can order whatever breaker combination and length you choose to.

http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=PDPM277H

[BillP]

As i said before, the list is correct, but there are no combinations without extenders to match 32A and 16A monophasic circuits.
The only combinations available in the 32A range are:

32A
PDM1332IEC-3P
PDM1332IEC-3P-2
PDM1332IEC-3P-3

20A
PDM1320IEC-3P-1
PDM1320IEC-3P-2
PDM1320IEC-3P-3

16A
PDM1316IEC-3P

Message was edited by: fedelang

[upsguy_apc]

There is actually a pretty good reason the Breaker/whip module only has extenders available and not lenght to order.

The 400V/230V 5 wire whips are made to multiple lengths so that you can run the whip directly to the rack you want.

The 400V/230V 3X1 Breaker modules take the 3 single phases and run them each to a single phase connector. All the connectors should not be going to the same rack so you wouldn't want 3 single phase whips all the same length because you would end up with to much slack or not enough to reach the rack mount PDU so the correct thing to do in this case is to use a extender to reach each rack. If you are planning on running all three whips to the rack you would better off using 3 phase PDU's in the rack.

With this many whips and racks you would have been better off using 32A 3 phase rack mount PDU's and you could have avoided using the extenders and all of the mess.

[BillP]

You are correct again, but not entirely. International part numbers for Rackmount PDUs are very limited in comparison with US RmPDU portfolio. There are no 7kW (equivalent to a 32A monophasic) three-phase pdus, you have to jump for 11kW PDUs or 22kW PDUs. And summing up thats why the solution with extenders is a pain.

BTW the solution came right out from APC ISX Configuration tool, with extenders included, and was approved that way by the staff despite my observations.

Even if APC could design a full range of whip sizes, the solution still fails for all non-standard datacenter layouts (most of them). Maybe next refresh could bring the Schneider Electric Powerclip technology to avoid this trouble.

[BillP · Accepted solution]

I recently opened a post asking for the possibility of cutting APC power wheeps (http://forums.apc.com/spaces/6/racks-rack-accessories-cooling/forums/general/2836/understanding-pdu-...), I anticipated what the below pictures show.

There's no way you can make room for so many connectors to feed rack PDUs, not in a regular canalization. PDMs have a flawed design, they should bring a guaranteed hardwire connection. After all If you feel the need to change or replace some PDM it would be a major pain to free the wheeps through the whole installation.