Power Supply – Common Cable Sizes for PSU Connections

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Most all wall plugs in North America are type A or type B.

What type of cable end usually plugs into an aftermarket PSU?

I am pretty sure it is the C13 cable, but not many PSUs make this specification.

I am asking because I am hoping to purchase an HP E7681-63001 PDU, plug it into my 30A dryer plug, and plug 4 * 1,400 PSUs into it. I assume I will need 4*male-female c13 cables to do so. Am I right?

Best Answer

The C13 (often referred to in industry as an IEC cable) is an absolute standard for computer PSU mains connections. Cables with 15A north american mains (NEMA 5/type B) male end* and IEC female end are thus ubiquitous. Note that the HP PDU, since it's intended for direct use with computer equipment, features female IEC connectors. So you need an IEC->IEC cable (commonly referred to as IEC Extension) rather than a mains->IEC cable to connect devices to this PDU. These cables are a little less common, but still cheap.

Note that the dryer receptacle you have now (probably a NEMA 14) will not be matched by the connector that comes with the PDU, since data centers almost universally use the NEMA L-series "twist-lok" connectors for mains service. So, you'll need to splice on a new cable, which you should be careful with since this will carry around 240v 20A (plus or minus a lot, depending on machine load) in the configuration you describe. In an enterprise environment any non-locking connector is considered a hazard (unreliable, unsafe), and I think this should be wisely carried to homes. What I'm saying is that it might be worth it to have a twist-lok connector installed.

(*) In the theatre industry we call these Edison plugs. I'm not sure how common the term is in IT. There are a lot of standards that define these plugs, NEMA 5 is cited the most.

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