There’s More to Power Cables in Your Network Than You Might Think

There’s More to Power Cables in Your Network Than You Might Think

Posted by Troy Snobecy on Jul 25th 2022

In our last blog, we discussed PDUs and how to select the right one for powering your data center equipment like servers and switches. Throughout the network, PCs and peripherals like monitors and printers also need power to connect to outlets. When it comes to providing secure and reliable power connections for all your networking equipment, you need the right power cable. 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 while NEMA 5-15 is used to denote both plugs and receptacles (outlets) using the “P” or “R” suffix (5-15P and 5-15R), IEC-320 connectors use an even number for the plug (male) and an odd number for the mating receptacle (female), with the plug being the higher of the two numbers—C13/14, C15/C16, C19/C20, and so on.

With IEC-320 connections used throughout the world on the majority of equipment, hybrid power cables with NEMA 5-15P to C13, C15, or C19 receptacles are typically what you’ll need throughout your network for connecting equipment to NEMA 5-15 receptacles. C14 inlets are used on most PCs, printers, and monitors, which requires a C13 receptacle on one end of the power cable. C16 and C20 inlets are found on most switches and servers, which requires 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 are available 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 rating. C13/14 are rated at 70°C, while C15/C16 are rated at 120°C for higher-temperature applications such as PoE switches. While a C15 connector will fit into a C14 inlet, a C13 connector will not fit into a C16 inlet. The main reason for this is that a higher-rated power cable can be used in lower rated equipment, but a lower rated power cable cannot be used for higher rated equipment.

Why Such a Variety of Colors?

When it comes to power cables, the different connector types all look pretty similar with their 3-prong plugs and receptacles. Short of carefully examining the often difficult-to-see specs on the cable jacket, it’s impossible to differentiate amperage. Color coding is a great way to keep power cables organized by their type and purpose for overall better management and easier troubleshooting to reduce outages and downtime. That’s why Cables Plus USA offers power cables in a wide range of colors.

One of the primary uses of color coding is to differentiate between primary and secondary power, which is required for redundancy in the data center. Rather than using the typical black power cables that come with most equipment, data centers use RED power cables for primary power, and BLUE power cables for secondary power. Many data centers will even match color outlets on PDUs to the power cable color. Other reasons for color coding may be to distinguish voltages, types of equipment, applications, and even speed. For example, color coding can be used to distinguish 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 especially helpful 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 versus when all black power cables are used.

What Else Should You Consider?

While determining connector type, current, temperature, and color will help you narrow down which power cable you need, there are additional considerations. When it comes to power connections in the data center where reliability and uptime are critical, you may want to consider using locking power cables that help prevent accidental disconnects due to loose connections. For use with lockable receptacles available on a variety of vendors’ PDUs, locking cables feature locking clips on either side of the connector that keeps them firmly plugged in. Dual-locking cords feature locks on both the plug (male) and receptacle (female) side for securing locking power cables into the outlet AND the equipment.

You also need to consider the length of the cable to ensure it will reach from the power outlet to the equipment. At the same time, you don’t want too much slack as that can make management more difficult and impede airflow in racks and cabinets. Within racks and cabinets, length is also often dependent on the location and type of PDU. For example, having a horizontal rack-mounted PDU near the top of a cabinet may require a 15-foot power cable to reach a server located near the bottom, while using vertically-mounted PDUs may only require a 1 to 2 foot power cable to make short adjacent connections.

Jacket rating and standards compliance are also considerations. Power cable jackets are typically SJT or SVT. SJT power cables have thicker insulation and are oil resistant for use in environments that endure medium stress, while SVT cables are for light-duty applications. SJT cables are also able to support a wider range of gauges. Depending on your location and specifications, you may also need to ensure compliance with certain industry standards and regulations. For example, in North America, you’ll need UL listing for the United States, and cUL listing for Canada. You may also need to meet environmental regulations like RoHS (Restriction of Hazardous Substances) or REACH (Registration, Evaluation, Authorization and Restriction of Chemicals).

While the various specs and features available 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, just contact us at sales@cablesplususa.com or 866-678-5852 and we will help determine what is right for you.