C13, C14, C19 and C20 Power Cords Explained: Which You Need
Rack power cords use IEC connectors, and the letter-number codes describe which end is which and how much current it carries. Getting one wrong means a cable that does not fit or one that is under-rated. This covers reading the codes.
What do C13, C14, C19 and C20 mean?
They are IEC 60320 connector types. The rule that makes them readable:
Even numbers are inlets (male, on equipment). Odd numbers are the connectors that plug into them (female, on the cable).
So a C14 inlet on a server takes a C13 connector from the cable. A C20 inlet takes a C19.
C13/C14 is the standard pairing for servers, switches and most rack equipment, rated to 10A.
C19/C20 is the higher-current pairing, rated to 16A, used for high-draw equipment and for feeding PDUs.
They are physically different sizes. A C13 does not fit a C20 inlet, and a C19 does not fit a C14.
What does a C13 to C14 cable do?
It connects a PDU to a device, which is the most common cable in any rack.
A rack PDU has C13 outlets. A server has a C14 inlet. So the cable has a C14 connector at the PDU end and a C13 at the server end. Listings describe this as a C13 to C14 or C14 to C13 cable, which is the same thing read from opposite ends.
This is why rack power cords usually have IEC connectors at both ends rather than a wall plug — the wall plug is on the PDU, not on each device. Our PDU guide covers outlet counts and types.
Reading the rest of the code
A typical part number reads something like C13C14-15A-PLBK-6F. The parts:
C13C14 — the two connector types, in this case a C13 at one end and a C14 at the other.
15A — the current rating, here 15 amps. Common ratings are 10A, 13A and 15A depending on region and conductor size.
PLBK — the colour code, here black. Colour is used to identify power feeds; many data centres use one colour for the A feed and another for the B feed.
6F — the length, here 6 feet. Cable lengths are usually quoted in feet or metres.
Conventions vary between manufacturers, but connector type, rating, colour and length are the four things every code carries.
Locking IEC cords
A variant worth knowing about.
Standard IEC connectors can work loose from vibration or from cables being disturbed, and a power cord that falls out of a server is an outage. Locking cords have a latch that grips the inlet and releases only when a tab is pressed.
Different manufacturers use incompatible locking mechanisms, and a locking cord from one system may not latch into another vendor’s equipment, though it will still connect as a normal cord. Where you have redundant supplies and racks that get worked in, locking cords are worth the small extra cost.
Choosing the right cord
Five things.
Connector types at both ends, matched to the PDU outlet and the device inlet.
Current rating at or above the device requirement. An under-rated cord is a fire risk, not just a performance issue.
Length. Long enough to route through cable management without strain, short enough not to create a loop of slack behind the rack. Our rack depth guide covers rear clearance.
Colour, if you use colour to identify power feeds.
Locking or standard.
And one thing people forget: redundant power supplies need two cords, one per supply, and ideally fed from different PDUs. Our PSU redundancy guide covers why one feed defeats the redundancy you paid for.
Frequently asked questions
What is the difference between C13 and C14?
C14 is the inlet on equipment; C13 is the connector on the cable that plugs into it. Even numbers are inlets, odd numbers are the mating connectors. Both are rated to 10A.
When do I need C19 and C20 instead?
For high-draw equipment and for feeding PDUs. C19/C20 is the 16A pairing. They are physically larger and do not interchange with C13/C14.
What does a code like C13C14-15A-PLBK-6F mean?
Connector types at each end (C13 and C14), current rating (15A), colour (black), and length (6 feet). Conventions vary but those four things are always carried.
What is a locking IEC power cord?
A cord with a latch that grips the inlet and releases only when a tab is pressed, so it cannot work loose. Locking mechanisms differ between manufacturers and may not latch into another vendor’s equipment, though they still connect normally.
Can I use a lower rated cord if the device draws less?
Use a cord rated at or above the device requirement. An under-rated cord is a fire risk, not a performance question. When in doubt, use the higher rating.
How many cords does a server need?
One per power supply. A server with redundant supplies needs two, ideally fed from different PDUs, or the redundancy you paid for is defeated by a single feed.
Tell us your PDU outlet type, device inlet and the run length, and we will specify the cords for the whole rack in one list.
