Custom cable assemblies that are used to transmit data are especially vulnerable to interference from heavily electronic environments. It is essential to protect cable assemblies from electromagnetic interference (EMI) through the use of shielded cable assemblies. Shielded cable assemblies are used in a number of different fields and can be extremely useful in protecting data.

But what exactly are shielded cable assemblies, and what are they necessary? We’ll show you the finer points of these remarkable cables, why they are needed, and a few of the arenas in which they are best put to use.

shielded cable

Electromagnetic Interference: The Danger to Data

In electronically heavy environments like offices or data centers, there is significant electromagnetic interference that can disturb the transmission of data. Also referred to as “electronic noise”, EMI can interfere with data transmission to either partially corrupt or completely destroy the data. This interference is due to either electromagnetic conduction or electromagnetic radiation from the external electrical components within the area. The source of the EMI could be from other machinery, electronic equipment, or a naturally occurring phenomenon.

The cable assemblies used in electronically noisy areas need to be protected from EMI. EMI can significantly impact the effectiveness of data transmission using cable assemblies. By interfering with the cable assemblies’ ability to transmit data effectively, EMI can be a severe issue for an unshielded cable assembly. While a cable's insulation and jacket helps protect the conductors from moisture, breaks, and kinks, they do not protect from any type of EMI.

Shielded Cable Assemblies: Defending the Data

Because EMI is a prevalent problem in any number of work environments, shielded cable assemblies are all the more critical for data protection. Shielded cables are made with an additional layer of protection on the inner cable to act as a barrier from EMI. The shield is installed around the transmitting conductors and functions in two ways to defend against EMI data corruption.

The two primary ways that a shielded cable assembly protects the conductors from EMI are:

  • Reflecting energy: First, the shield within a cable acts as a physical shield that deflects the energy from EMI and disperses it away from the conductors. This shielding effectiveness can vary based on the thickness of the shielding, the materials used, and the purpose of the custom cable assemblies.
  • Ground the energy: The second way that a shielded cable assembly serves to protect the conductor components is to conduct the energy from the EMI around the outside of the inner cable and bring the electronic noise to a grounded state.

Shielding Types: The Particulars of Conductor Protection

Depending on the cable assembly's use, the shielding type can vary between two shielding types or have a combination shielding of both. There are a few main methods of shielding used to protect cable conductors from EMI: foil shielding and braided shielding.

Braided shielding

The second method of shielding is known as braided shielding. Braided shielding is made by weaving minuscule strips of metal that are braided together in between the insulator and the jacket. These shields are typically created using tinned copper. Braid shielding is heavier and more durable than foil shielding. This method provides more flexibility, as well as a longer flex life. This design helps defend against low-frequency EMI and is helpful in grounding such interference.While braided cable shields are more durable than foil shields, they do have a downside. Unfortunately, the woven nature of the braid cannot cover the cable entirely and has some vulnerability to some EMI effects. Typically, braided shields cover 70-90% of the conductor. In addition, because the braid requires more metal, it is a bulkier option that is typically more expensive than foil shields.

Spiral Shielding

The final method of shielding that will be discussed is spiral shielding. Spiral shielding is made by wrapping a series of parallel strands of metal in a spiral around the insulator of a cable. Spiral shielding is only used to block the high-frequency EMI that is typically found in sound and audio equipment. This type of cable shielding is effective at blocking high-frequency EMI but is not very flexible or diverse. Cables that use spiral shielding require a specific coiling method to match the form of the spiral and will break easily if not cared for properly.

Foil shielding

The first method is known as a foil shield which is the most effective method of completely covering the conductors. Foil shielding is made by wrapping a thin layer of metallic material in a spiral between the insulation and the jacket of the cable. Foil is typically made from aluminum foil or a narrow strip of copper that has been adhered to a polyester or polypropylene film. Foil shielding is lightweight and cost-effective. Because foiling is the only option that completely covers the surface of the cable, it is the most effective at blocking electrostatic interference.Even though foil shielding is effective at blocking the damaging effects of EMI, it does have a few flaws. First, foil shielding does not offer much in the way of flexibility. Because of the nature of the foil material, it can chink and break if it suffers a hard impact.

Combination shielding

The third option for cable shielding is really a combination of both foil shielding and braided shielding. Combination shielding, or composite shielding, is the best of both worlds because you have the full coverage from the foil shield and the flexibility of the braided shield. By combining the best qualities of foiling and braiding, these cable assemblies have the maximum protection from both electromagnetic static and low-frequency EMI.Combination shielding is best used in electronically noisy environments such as office buildings, data centers, and manufacturing environments that utilize heavy machinery. Composite shielding offers the best protection from EMI and can be used in a wide range of applications. The downside to combination shielding is that they tend to be more costly as they are made by using more materials and have a more intense production process.

Application for Custom Shielded Cable Assemblies

There are nearly limitless fields in which shielded cable assemblies are necessary. As diverse as the landscape of work environments can be, the list of places where custom shielded cable assemblies can be used is equally diverse. Because shielded cable assemblies provide protection for the data transmitted with the cables themselves, shielding is a vital component in many industries such as:

The medical field

From the heaviest medical equipment like a magnetic resonance imaging (MRI) machine to the smaller equipment like a heart monitor, the medical field is full of technology that utilizes shielded cable assemblies. Because the data being transmitted is used for diagnoses, monitoring vitals, and life-saving procedures, it is imperative that it be uncorrupted by any EMI. Hospitals and clinics have a lot of equipment that produces EMI and require cable assemblies to be protected from the damaging effects of that energy. The consequences of corrupted or lost data could be catastrophic and literally mean the difference between life and death. That is why it is so important to have reliable shielded cable assemblies within the medical field.

Technological and telecommunications

Another common application of custom shielded cable assemblies is within the technology and telecommunications industries. In thesis environments, massive amounts of data are transferred every second of every day. While this staggering amount of data keeps the world connected, it also produces enormous amounts of EMI that can be dangerous for data transmission efficiency. That’s why shielded cable assemblies are crucial in the technological and telecommunications sectors. Dependable custom shielded cable assemblies are essential to the continued use of telecommunications services, internet providers, and all forms of technical industries.

Original Equipment Manufacturers (OEMs)

Another industry where custom shielded cable assemblies are commonly put to use is within OEMs. OEMs utilize incredible machinery to produce parts, electronic equipment, and a plethora of other equipment. Because of the machinery operated, the industrial control panels, and the computer systems used daily, the cable assemblies transfer incredible amounts of data and power just to keep up with the daily manufacturing process. Therefore, EMI can be a consistent issue for OEM companies. Custom shielded cable assemblies help protect the power and data that is transferred in OEM factories. Custom shielded cable assemblies allow the OEM machinery to function properly and continuously throughout the daily manufacturing process and operations.

Automotive, industrial manufacturing, military, and more

The list honestly could go on and on for custom shielded cable assemblies applications. These diverse cable assemblies can be found under the hood of nearly every vehicle, industrial manufacturer, military equipment, and a wide range of other industries.

Let Meridian Cable Build Your Custom Shielded Cable Assembly

Meridian Cable is proud to be a leading manufacturer of custom shielded cable assemblies with decades of experience. Our in-house engineers work with you throughout every step of the design and prototyping process to ensure that your custom shielded cable assembly is perfect for your project. Contact our team to get started today.