A power cord is an essential element for all the cord connected electrical devices. It powers up your devices. Generally, power cords are connected in two ways.
- Non-Detachable: It consists of a plug, the cordage, and a strain relief device. It is used to secure the cord to equipment enclosure.
- Detachable: It is also known as power cord set. It consists of a plug, cordage, and a connector or receptacle.
Although when it comes to regulatory approvals, these cables are little tricky to understand. Let’s go through the brief of power cords which are intended for use in ITE and consumer products applications.
Before we begin, it would be good to note that power supply cords typically have two to three wires. ‘line’, ‘neutral’ and ‘ground’. Here are the standard IEC 60446 approved color codes:
- In North America, the line wire is black, while it is either brown or grey elsewhere.
- In North America, the neutral wire is white colored, while elsewhere it is blue colored.
- In North America, the ground wire is green, while at all other places, it’s green with yellow stripes.
When you look for the buying options, it is important to ensure that the electrical rating of the power cord is higher than your equipment rating. Because an under-rated power cord may harm your system, cause overheating and an electrical fire. In general cases, your plug would need at least 125% of the rated current for the equipment. In North America, power cords designed to use with ITE equipment are rated as 125Vac/10A.
Here’s the break down about the power cords and their components:
Non-Detachable Power Cords
These power cords are hard-wired to the equipment. In general cases, you don’t need to remove the cord from the equipment.
To attach the stripped end of a non-detachable power cord there is a lug/ring terminal. One end of the terminal consists of a metallic ring or a loop that is attached to a power terminal post. The other end is generally crimped on the stripped power cord wire. One more important thing to remember is, when utilizing this form of terminal, the crimp tool should be standard.
Manufacturers who own large equipment and need to ship power supplies occasionally might have chances that power supply cords get damaged during shipping. In such scenario, U.S recognized NRTLs (Nationally Recognized Testing Laboratories) allow the shipment under the following conditions:
- Why the power cord needs to be disassembled.
- The assembly of the disassembled equipment must be executed by qualified service personnel.
- Detailed assembly instructions must be provided that address all aspects of the reassembly, including the connection of the main earthing terminals.
- Instructions that state that no replacement cord would be used other than the one shipped with the product.
- A suitable method of securing the power cord to the enclosure is provided, such as a strain relief grommet.
It is also known as a line cord, main cord, or power cable. It consists of a flexible cord with electrical connectors male and female. The male end is attached to a molded electrical plug. The female consists of a molded electrical receptacle. This connection method is meant to prevent an exposed live prong or pin that could cause an electric shock. The male plug connects to the electrical source, while the female connector attaches to the piece of equipment. Overcurrent protection fuse is another component of the cord.
That’s pretty much it about the power cords connection types. But it’s a vital part to understand the plug and cordage certifications and specifications based on their connection types. In North America, the NEMA 5 family of plugs is the most common type used. The NEMA 5 plug typically has a male plug featuring two flat blades. For example, you can consider buying NEMA 5-15 to C13 power cords as they meet all the industry standards. It does not have a current rating higher than 20 amps. For high-rated current, a NEMA Power Cords featuring the NEMA L14-30P plug and the NEMA L14-30P is rated at 30 amps.
Considering Cordage specifications, in North America, most commonly used cables are SVT, SJT, SJTW, ST, SPT-1, and SOW. While in Europe, cables must have approval and carry the “◄HAR►” mark on them.
We can clearly state that each country has their own standards of approvals. Considering the North American developing standards, NEMA (National Electrical Manufacturer Association) certify and declare the approved cords as NEMA Power Cords. These cables are typically used for ITE. Rest of the countries use IEC 60320 standard cords. It is an international standard for the certification of the power cord components. So, the next time if you want to buy 5-15 to C13 power cords you will find NEMA 5-15 to C13 power cords standardized. In the USA, the standard used to examine power cords is UL 817.
As this article has demonstrated, the power cords aren’t easy to understand. There are a number of components used, different regulations followed country wise. It is an essential conduit through which the electricity flows. Therefore, you need to take care while buying. They must meet the maze of international regulations and certifications for the power cords.