Video – Solving power connector confusion

Why talk about network power connectors?

Here at Network Sherpa base camp, we’re all about removing confusion and saving time.   I’ve always had a bit of difficulty differentiating between the connector types,  PDU’s,  inlets outlets and country specific power cords. In this post I share my learnings.

In the video below I focus on the commonly used low power IEC 320 series C13/14 connectors.  If you want further detail or more info about other connectors, then check out NetworkingNerds’s great post on this topic.

Check out this quick 5 minute you-tube video on power cords.

The flow of power

Inlet – it’s where the power flows into the networking device. These inlets are pretty standard, almost always a C14 or C20 recessed connector.

Outlet – where the power flows out from the supply, normally a PDU or power distribution unit, sometimes called a power strip.  The outlet type can vary widely.  Some companies choose PDUs with IEC standard (C13/C19) outlets. Sometimes you’ll find PDUs with outlets that match the country specific power standard such as a NEMA 5-15R(US) receptacle, or a BS1363 (UK/Ireland) socket.

The power cord helps you transfer the power from the outlet to the inlet. I know that APC sell locking C14 power cords, which help prevent accidental removal of the power cord.  I like the idea but haven’t really used them much, and suspect that you’ll pay a premuim and need an APC pdu to get the benefits.

On being Male – it’s in the pins

When it comes to gender (of connectors!) I get a little confused.  The C13 connector has a plastic connector which is inserted into the power inlet,  but that C13 connector receives the pins of the inlet.  So…is the C13 a male or a female connector?

For electrical connectors the answer is straightforward: ignore the plastic and focus on the pins.  If it has pins it’s a male connector.

Female to male

Alright now that I’m sure that ‘the pins’ identify male, how can I remember the gender of inlets/outlets and power cords.  That’s simple too. Wikipedia tells me that power always flows from female-to-male. So the outlet is always female (no pins) and the inlet is always male (pins).

Finally, how do you remember which of  C13/C14 is female or male.  Well as long as you think of them as a couple then the female-to-male power principle still holds:

C13/C14 = Female/Male    C19/C20 = Female/Male.

Sherpa Summary

  • Spend a little time learning the terminology and you’ll reduce frustration and lost time due to miscommunication. If you’re a new engineer this knowledge will make you stand out from the crowd.
  • Power flow is female-to-male. From Outlet (no pins) to Inlet (pins), or from odd (C13 or C19) to even (C14 or C20).
  • When ordering a new device, verify it’s inlet type: C14, C20 or fixed (eg. Nexus 7500W)
  • When doing your site survey, check the PDU. Does it have a C13/C19 type outlet or a country specific socket or receptacle?
  • Order the right cable – don’t just ‘assume’ the bundled cord will be right for you.
  • It can be really difficult to find the right power-cord SKU sometimes. Now that you have the terminology, you can ask your VAR for the SKU matching the specific cable you require, or go buy one quickly when the wrong cable inevitably shows up.

 

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4 thoughts on “Video – Solving power connector confusion

  1. Great post, thanks a lot. The Nexus 7500 fixed power supply – I wish vendors would stop making fixed power supplies. I’ve had so many issues in the past on campus implementations where I would find a spare 4500 only to learn it had a fixed power supply and end up having to order new power supplies or an electrician.

    • Hey Will,
      Agreed the fixed power cord is a bummer. Even if you do manage to find the correct receptacle, the length of the power cord can be a real pain. For overhead the cable could be too short, but for underfloor connection you can end up with a cable coiling up and blocking plenum space. Joy 🙂

  2. I have a PDU with 20 x C13 (female) plugs. However, one server needs C19 (female) plugs. Can I simply use an adapter to connect a C19 intended device to a C13 plug?

    • Mike,
      No, don’t do that. Remember it’s not just about the connectors.

      C19/C20 cables have a higher power rating than C13/C14, and you risk a fire in your datacenter or a blown PDU/circuit if you connect an appliance to a lower-rated outlet, or using a lower-rated cable.

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