A detachable power cord looks like a single part and behaves like three. There is a wall plug, a length of flexible cordage, and an appliance coupler. Each has its own rating, each is governed by a different part of the standard, and the assembly is only as good as the lowest of the three. The reason this matters is that the middle of the three is the part nobody reads: the coupler on a laptop supply and the coupler on a server power supply can look like the same connector, be the same connector, and still carry two different current ratings depending on which side of the Atlantic the assembly is certified for.
A Cord Set Is Three Parts, and the Lowest Rating Wins
The three parts are separate specifications that happen to be assembled together.
The wall plug fixes the regional interface and the current available at the socket. The cordage carries the current and has to survive being flexed and coiled for the life of the product. The coupler at the equipment end fixes the current the appliance can draw and the temperature the interface has to tolerate.
A cord set rated 10 amperes on its coupler and 15 on its plug is a 10 ampere assembly. That sounds obvious written down, and it is the mistake made when a buyer specifies the coupler and lets the rest be whatever the factory has on the line.
A cord set is three independently rated parts
The Same Coupler, Two Current Ratings
Here is the fact that most frequently catches out a specification written in one region and manufactured in another. The IEC 60320 coupler ratings are published in two columns, because the same part is rated differently for North America and for Europe.
Coupler | Pin temperature | North America (UL / CSA) at 250 V | Europe at 250 V | Earthed |
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C1 / C2 | 65 °C | 0.2 A | 0.2 A | No |
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C5 / C6 | 65 °C | 2.5 A | 2.5 A | Yes |
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C7 / C8 | 65 °C | 2.5 A | 2.5 A | No |
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C9 / C10 | 65 °C | 6 A | 6 A | No |
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C13 / C14 | 65 °C | 15 A | 10 A | Yes |
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C15 / C16 | 120 °C | 15 A | 10 A | Yes |
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C15A / C16A | 155 °C | 15 A | 10 A | Yes |
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C17 / C18 | 65 °C | 10 A | 10 A | No |
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C19 / C20 | 65 °C | 20 A | 16 A | Yes |
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C21 / C22 | 155 °C | 20 A | 16 A | Yes |
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C23 / C24 | 65 °C | 20 A | 16 A | No |
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Look at the C13 row, which is the coupler on the overwhelming majority of desktop equipment. Fifteen amperes in North America, ten in Europe. The C19 row behaves the same way, at twenty and sixteen. The smaller couplers do not split, which is why the split is easy to miss: it only appears on the two families that carry real current.
Three consequences follow. A cord set built to the European rating is a 10 ampere part even if the coupler body is identical to one carrying 15. A buyer who orders against a North American specification and receives European-rated parts has two thirds of the intended capacity, with nothing on the outside to show it. And a product sold into both markets needs the cord ordered as two articles.
The same coupler carries two current ratings
The Same Shape at Three Temperatures
The coupler tables carry a third variable that is even easier to overlook: the pin temperature. The same geometry appears at three temperature classes under three different designations.
Geometry | 65 to 70 °C | 120 °C | 155 °C |
|---|
14 mm pin spacing, 10 A class | C13 / C14 | C15 / C16 | C15A / C16A |
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13 mm pin spacing, 16 to 20 A class | C19 / C20 | Not published | C21 / C22 |
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The point of reading this table is what it says about the designations. Three parts share a geometry and carry three separate standard sheet numbers, which is the standard’s way of saying they are not the same part. A C15 is the 120 °C version of a C13; a C15A is the 155 °C version; a C21 is the 155 °C version of a C19. In the field these are used for the equipment that runs hot: the 120 °C pair is the one seen on recent servers and network equipment, and the 155 °C pair is used in stage lighting and industrial equipment.
The practical rule a specifier can take from it without needing the standard in front of them: match the pin temperature class to the equipment, not to the socket. A hot-running appliance that has a C14 inlet expects a cord with the higher temperature class at both ends.
One geometry at three pin temperature classes
Which C Number Applies
Strip away the designations and the family divides on three properties.
Type | Pin spacing | Earthed |
|---|
C1 / C2 | 6.6 mm | No |
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C3 / C4 | 10 mm | No |
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C5 / C6 | 10 mm | Yes |
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C7 / C8 | 8.6 mm | No |
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C9 / C10 | 10 mm | No |
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C11 / C12 | 10 mm | No |
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C13 / C14 | 14 mm | Yes |
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C15 / C16 | 14 mm | Yes |
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C17 / C18 | 14 mm | No |
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C19 / C20 | 13 mm | Yes |
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C21 / C22 | 13 mm | Yes |
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C23 / C24 | 13 mm | No |
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Note the pair that differs only in earthing. The C13 and the C17 have the same pin spacing and the same current class, and one has an earth contact while the other does not. The C19 and C23 repeat the pattern at the higher current. Earthing is not a quality tier; it follows the equipment class, and it is why a cord that physically fits should still be checked against the inlet.
The Low-Current Families
Not every coupler family carries a meaningful current, and three of them are worth recognizing by sight because they appear on consumer equipment rather than in racks.
Family | Common name | Current | Earthed | Maximum length |
|---|
C1 / C2 | Shaver connector | 0.2 A | No | 2 m |
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C5 / C6 | Cloverleaf | 2.5 A | Yes | 2 m |
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C7 / C8 | Calculator or figure-eight | 2.5 A | No | 4 m |
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Two of the three are molded only and never available as a rewirable part, which is the C1 and the C5. The C7 is usually molded and occasionally supplied as a rewirable part, which is why figure-eight leads turn up cut and re-terminated more often than the other two.
Recognizing them matters for one reason. A buyer who specifies a 10-ampere cord set for a low-current device has bought capacity the device cannot use, and the figure-eight family is where that happens most often.
Length and Conductor Size Are Linked
Cord length is not a free choice either. At least one published reference ties the permitted maximum length of a C13 or C14 cord set to the cross section of its cores: two meters when the cores are 0.75 mm², and up to ten meters otherwise.
The reasoning is the same arithmetic that governs any cable: a longer run of a smaller conductor drops more voltage and runs warmer for the same current. The same reference publishes different limits for other couplers, including four meters for the C7 and C8 pair, where the current is only 2.5 amperes.
Two things follow. A very long cord set in a small cross section is not a bargain, it is a different rating. And where a product needs a long cord, the answer is the next conductor size up rather than the next length down.
The Types That Were Withdrawn
The standard is not static, and two coupler families have been removed from it. The C3 and C4 pair, and the C11 and C12 pair, are shown in reference tables for information and are no longer available as products.
The C1 and C2 pair, originally the shaver connector, survives in the tables while the requirement that created it has gone, because shavers moved to direct current. It is also one of two families that are molded only and never available as a rewirable part; the C5 and C6 cloverleaf is the other.
The reason to know this is procurement. A drawing that specifies a withdrawn coupler cannot be built as drawn, and the substitution is a design change rather than a sourcing one.
C13 Is Not a Kettle Lead
The C13 is routinely called a kettle lead, and the name is wrong in a way that occasionally matters. The kettle connector in the strict sense is the C15, the high-temperature version, which is a C13 shape rated for the hotter environment.
The distinction is worth keeping because the two are specified to different temperatures. A purchase order that asks for a kettle lead and receives a C13 has the right shape at the lower temperature class: fine for a monitor, not what was intended for equipment that runs hot.
Molded and Rewirable
Couplers come two ways, and the two are not interchangeable in a specification.
A molded cord set is assembled and sealed at the factory, so cordage and coupler become one part. It is the ordinary form for a cord shipped with a product and the only form available for some types.
A rewirable coupler is a separate part that a person can terminate onto field cordage. It is the form used for replacement and for assemblies built to a length that no catalog carries.
Both tables in this article describe the coupler, and the coupler is the part that carries the rating. A rewirable C13 and a molded C13 are rated the same, and the assembly around them is where the difference in reliability lives.
Earthed and Not Earthed
The earthing column is not a style choice, and it is not a statement about quality. It follows the class of the appliance.
Where the equipment relies on a protective earth for its safety, the cord set has to carry the earth contact, which is why the C13 and the C19 have one. Where the equipment is built so that no protective earth is needed, the coupler is made without one, which is why the C7 and the C23 do not.
This is why a cord set should not be moved between appliances on the basis that it fits. The interface tells you the geometry matches, not that the ratings agree.
Two Things a Cord Set Is Not
The first is an extension lead. A cord set connects equipment to a socket outlet, and the published length limits exist for that application rather than for reaching across a room.
The second is a regional part. One coupler family spans every market, and the coupler is not what changes. What changes is the current rating, the wall plug on the far end, and the approvals the assembly carries.
What to Ask Before You Order
- The coupler designation at the equipment end, by C number.
- The market the assembly is for, because the same coupler carries two current ratings.
- The pin temperature class the equipment needs, which decides between the standard and the high-temperature version.
- The wall plug type for the destination market.
- The conductor cross section, and whether the requested length is permitted on it.
- Molded or rewirable, and whether the coupler type is available in the form asked for.
- The earth contact, matched to the equipment class.
The Short Version
A detachable power cord is three independently rated parts, and the lowest rating governs. The same coupler geometry is rated 15 amperes in North America and 10 in Europe on the C13, and 20 against 16 on the C19, so a cord set is a regional article even though the coupler is universal. The same geometry also exists at three pin temperature classes under three designations, and at least one published reference ties the permitted length of a C13 cord to the cross section of its cores. Specifying a cord set means choosing all three parts against the market, the temperature and the current rather than specifying the connector and accepting whatever comes with it.
We build cord sets to a stated coupler, length, cross section, temperature class and market, and supply the test documentation that goes with the approvals the destination requires. Tell us the equipment inlet, the market and the current, and we will tell you which assembly that is.
Sources
- Qualtek, "IEC Connector Designations" reference chart — the designation of each appliance coupler by male inlet and female outlet; the maximum pin temperature for each type, being 65 °C for the C1, C5, C7, C9, C13, C17, C19 and C23 families, 120 °C for the C15 family and 155 °C for the C15A and C21 families; and two separate columns of maximum rated current at 250 volts, one for UL and CSA and one for Europe, which give 0.2 A for the C1, 2.5 A for the C5 and C7, 6 A for the C9, 15 A against 10 A for the C13, 15 A against 10 A for the C15, 15 A against 10 A for the C15A, 10 A for the C17, 20 A against 16 A for the C19, 20 A against 16 A for the C21 and 20 A against 16 A for the C23. The chart is published by a connector and cord set manufacturer and is cited here as the reference it is intended to be — https://www.qualtekusa.com/Catalog/AC_Receptacles/pdfs/connector.pdf
- Webber Electronics, "IEC Types" comparison table — the pin spacing in millimetres for each coupler pair, being 6.6 mm for the C1, 10 mm for the C3, C5, C9 and C11, 8.6 mm for the C7, 14 mm for the C13, C15, C15A and C17, and 13 mm for the C19, C21 and C23; whether each type is grounded, with the C13, C15, C15A, C19 and C21 earthed and the C1, C3, C7, C9, C11, C17 and C23 not earthed; the maximum amperage ranges, showing 10 and 15 for the C13 family and 16 and 20 for the C19 family; and the maximum pin temperature, at 70 °C for most types, 120 °C for the C15 and 155 °C for the C15A and C21. This second table is the corroborating source for the dual current rating, since it independently shows the C13 and C19 families each carrying two figures — https://www.webberelectronics.com/technical-info/iec-types/
- Leads Direct, "IEC Connectors" technical library — the statement that the maximum cable length for the C13 and C14 pair is 2 m on 0.75 mm² cores and up to 10 m otherwise, with a maximum of 2 m for the C1 and C5 families and 4 m for the C7; the maximum pin temperature for each family; the rated currents, being 10 A for the C13 and C15, 16 A for the C19, C21 and C23, 6 A for the C9 and 2.5 A for the C5 and C7; the observation that the C15 is the high temperature version of the C13 and is used extensively in recent server and network equipment, and that the C15A is for even higher temperature devices such as stage lighting and industrial applications; the note that the C3 and C4 pair and the C11 and C12 pair have been removed from the IEC 60320 standard and are shown for information only; the note that the C1 and C2 pair survives although the shaver requirement that created it has been removed by the change to DC power, and that the C1 and the C5 are molded only and not available as a rewirable part; and the observation that the C13 is sometimes wrongly called a kettle lead — https://leadsdirect.co.uk/technical-library/iec-connectors/
