Want to move to all 208V for server racks

Thu Dec 2 17:02:58 UTC 2010

On Thursday, December 02, 2010 10:58:52 am Jay Nakamura wrote:
> Anyone have any experience where some oddball equipment that couldn't
> do 208v and regret going 208v?  

Wall wart supplies will need changing, more than likely.

I have a few racks with 208V distribution (EMC 40U racks are built this way), and haven't run into many issues.  But you do need to watch carefully, and whatever you do do not wire a 5-15R or 5-20R (or any other '5-' receptable or 'L5-' receptacle) to 208; use the proper '6-' receptacles or IEC receptacles (as mentioned) for all 208 power.  This is typically mandated by NEC in new installations, and the electrician doing the distribution should be familiar with the NEMA connector chart.  See https://secure.wikimedia.org/wikipedia/en/wiki/NEMA_connector for more information on those connectors.

Also, if your customers provide their own UPS equipment that could be an issue, as very few UPS I'm aware of are multi-voltage input (APC SmartUPS 3000 is what I use typically, and that by default needs an L5-30R).

But if you provide a neutral with your 208 (using an L14 connector) you then can have mixed distribution with 120V available on 5-15R's but 208 receptacles for major power consumers in the rack.  That's what I've done in most of my racks that need 208 (like for 7609's and Cisco 12K), other than the EMC's, which use L6-30's for the rack input, and IEC receptacles for the devices in the rack.