How to Choose the Right Power Cable and Connector

Power distribution units, or PDUs, distribute power in the rack to active data center equipment like servers and switches. Equipment like PCs, monitors, and printers also need power. When it comes to providing secure and reliable power connections for all your networking equipment, you also need the right power cable and connector. While that may sound easy, it can be tricky with such a wide variety of specs to consider.

What are the Primary Specs?

When selecting power cables for your network equipment, the primary specs to consider are connector type, current, and temperature. 

NEMA 5-15 and IEC-320 C13/14, C15/16, and C19/20 are the most common connectors for making power connections, with NEMA used in North America and IEC-320 used internationally. It’s helpful to know that NEMA 5-15 uses a “P” to denote the plug and an “R” to denote the receptacles (5-15P vs. 5-15R. In contrast, IEC-320 connectors use an even number for the plug and an odd number for the receptacle, with the plug being the higher of the two numbers, such as C13/14, C15/C16, C19/C20, and so on.

IEC-320 connections are used throughout the world on the majority of equipment. To connect equipment to NEMA 5-15 receptacles, you will typically need a hybrid power cable with a NEMA 5-15P plug on one end and a C13, C15, or C19 receptacle on the other end. C14 inlets are common on most PCs, printers, and monitors, requiring a C13 receptacle on one end of the power cable. C16 and C20 inlets are found on most switches and servers, which require C15 or C19 receptacles. When using PDUs with IEC-320 C13 or C19 receptacles, you may need a hybrid cable with C14 or C20 plugs to C13, C15, or C19 receptacles, depending on the requirements of the equipment.

In addition to selecting your plug and receptacle, you also need to consider the voltage and amperage. In North America, 120 Volt power is the most common, while the rest of the world uses 220 to 240 volts. Most data center equipment today, including servers and switches, are designed to accept any voltage, and larger servers tend to be configured for 208 V for greater power capacity. Power cables come in 125 Volt or 250 Volt to accommodate the various requirements. You also need to look at amperage. While NEMA 5-15 and C13 are rated at 15 amps, most PCs require less than 10 amps, so it’s likely that you’ll only need 5-15P to C13 10 amp cables for computer connections.

Another key specification is the temperature rating. While C13/14 and C15/C16 may carry the same rating, C15/16 connectors feature a small notch that is used for differentiating between temperature ratings. C13/14 are rated at 70°C, while C15/C16 are rated at 120°C for higher-temperature applications such as PoE switches. A higher-rated power cable can be used for lower-rated equipment, but a lower-rated power cable cannot be used for higher-rated equipment as it poses a safety risk due to the potential for overheating. To prevent that from happening, a  70° C13 connector will not fit into a 120° C16 receptable, but a 120° C15 connector will fit into a 70° C14 receptacle.

Why Such a Variety of Colors?

Power cable connectors can appear similar, making it challenging to differentiate amperage without close inspection of the often-inconspicuous cable jacket specifications. Color coding provides an effective solution or organizing power cables by type and purpose, thereby simplifying management and troubleshooting to minimize downtime. That’s why Cables Plus USA offers a diverse range of colored power cables. 

In data centers, critical switches and servers often use primary and secondary power connections to ensure redundancy. Instead of relying on standard black power cables that come with most equipment, color coding clearly differentiates between these two connections. A common practice in many data centers is to use RED power cables for primary power and BLUE power cables for secondary power. Matching color outlets on PDUs to the power cable further streamlines the identification of primary and secondary power sources.

Beyond redundancy, color coding can also indicate various voltages, equipment types, applications, and even speed. For example, distinct colors can differentiate between PoE and non-PoE switches, 10 Gig and 25 Gig servers, web servers and application servers, or AV equipment and security equipment. This is particularly advantageous for maintenance—if you tell your tech to unplug the AV equipment with the purple power cable, they are far less apt to make a mistake compared to when all black power cables are used.

 

What Else Should You Consider?

Choosing the right power cable involves additional considerations beyond connector type, current, temperature, and color. In data centers, where reliability and uptime are paramount, consider using locking power cables  with lockable receptacles available on a variety of vendors’ PDUs to prevent accidental disconnections. These cables feature locking clips on either side of the connector that keeps them firmly plugged in, with dual-locking cords offering added security at both ends with locking clips on both the plug and receptacle side. There are typically two types of locking – P-Lock and A-Lock. P-Lock is more proprietary and used on specific vendors’ servers and PDUs, while A-Lock is considered universal and can lock into a variety of standard receptacles.

Cable length is also crucial. Select a length that reaches from the power outlet to the equipment without excessing slack, which can hinder management and impede airflow in racks and cabinets. Within racks, the required length often depends on the placement and type of  PDU. A horizontal rack-mounted PDU near the top of a cabinet might need a longer 15-foot power cable to reach a server located near the bottom, while vertically mounted PDUs may only require short 1-2 foot power cables for adjacent connections.

Finally, consider jacket rating and standards compliance. Cables with SJT-rated jacketing have thicker insulation and are oil resistant for use in environments that endure medium stress, while cables with SVT-rated jacketing are suitable for light-duty applications. SJT cables are also able to support a wider range of gauges. Depending on your location and specification, you may also need to ensure compliance with relevant industry standards and regulations, such as UL and cUL listings in North America and environmental regulations like RoHS (Restriction of Hazardous Substances) or REACH (Registration, Evaluation, Authorization and Restriction of Chemicals).

How Do I Know Which to Choose?

Because there are so many options when choosing a power cable, it’s important to know the power specification, required temperature rating, and plug/receptacle type of your equipment. To help you choose the right power cable, the table below includes typical options available in a range of colors.

Type	Plug (Male)	Receptacle (Female)	Voltage (Volts)	Current (Amps)	Cordage/ Conductor	Temp (°C)	Application
Standard	NEMA 5-15	IEC C13	125	10/15	14 AWG/3	70	Computers, networking equipment
High-Temp	NEMA 5-15	IEC C15	125	15	14 AWG/3	120	Networking equipment
Standard	NEMA 5-15	IEC C19	125	15	14 AWG/3	70	High-power equipment
Standard	IEC C14	IEC C7	250	2.5	18 AWG/2	70	PDU to double insulated transformer
Standard	IEC C14	IEC C5	125	10	18 AWG/3	70	Laptop chargers
High-Temp	IEC C14	IEC C15	250	15/13/10	14/16/18 AWG/3	120	High-temp equipment
Standard	IEC C14	ICE C13	250	15/13/10	14/16/18 AWG/3	70	Monitors, printers, networking equipment
Standard	IEC C14	ICE C19	250	15	14 AWG/3	70	High-power networking equipment
Standard	IEC C20	ICE C13	250	15	14 AWG/3	70	High-power networking equipment
High-Temp	IEC C20	ICE C15	250	15	14 AWG/3	120	High-temp equipment
Standard	IEC C20	ICE C19	250	16/18/20	14/12 AWG/3	70	High-power network equipment
Standard High-Power	NEMA 6-15	IEC C13	250	15	14 AWG/3	105	High-power networking equipment, gaming consoles, industrial machinery
A-Lock	IEC C14	IEC C13	250	10 or 15	18 AWG/3	70	Secure networking equipment connections, universal
A-Lock	IEC C14	IEC C15	250	15	14 AWG/3	120	High-temperature Secure networking equipment connections, universal
A-Lock	IEC C14	IEC C19	250	15	14 AWG/3	70	Secure networking equipment connections, universal
A-Lock	IEC C20	IEC C13	250	10 /15	14 AWG/3	70	Secure networking equipment connections, universal
P-Lock	IEC C14	IEC C13	250	15	18 AWG/3	70	Secure networking equipment connections, proprietary
P-Lock	IEC C14	IEC C15	250	15	14 AWG/3	120	Secure networking equipment connections, proprietary
Saf-D-Grid	Saf-D-Grid	IEC C14	250	15	14 AWG/3		AC and DC power, Cisco, Arista, and other data center switches

While the many plug and receptacle types, features, and specifications on power cables can seem overwhelming, the good news is that Cables Plus offers a complete line of power cables to meet virtually all your power connection needs with easy filtering capability on our website to refine by connector type, power, color, cable construction, length, jacket rating, and more. If you’re unsure which power cable you need for your network equipment, contact us today and we will help determine what is right for you.

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