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Low-Cost Cable Options for ISO 13485 Class 1 & 2 Medical Devices

Steven J Goodman
Written by Steven J Goodman
Posted on October 1, 2020 at 9:45 AM

Medical devices are used globally to diagnose health issues and provide life-sustaining care. These devices need to have quality parts and components to operate, including cable assemblies that provide a variety of functions. Due to the nature of these devices and the industry in which they are used, manufacturers must ensure quality management processes are put into place. If a product malfunctions while in use, it could put the patient's health in jeopardy.

The Federal Drug Administration (FDA) has regulations in place to ensure products meet quality standards when marketed in the United States. They have developed a classification system for every medical device based on the type, its risks to patients, the invasiveness of the product to patients, and how the device will impact the patient's overall health. In addition, medical device companies must also be certified under the ISO management system standards, ISO 13485, to ensure they have the quality management system in place that will allow them to create reliable devices that will not fail when placed into medical use.

Cable assembly used in medical imaging device.

Cable assembly used in medical imaging device.

Understanding ISO 13485

What is ISO 13485?

ISO 13485 is an international quality management standard that focuses on the medical device manufacturing industry. This standard applies to every device, and components that are within a device, even the cables and printed circuit boards (PCBs). This standard is to be used by manufacturers to create a comprehensive quality management system for the device's design, build, installation, and servicing. Certification organizations and auditors may also use ISO 13485 when performing auditing services or certification testing.

Manufacturers are not required to be ISO 13485 certified, although many companies will seek out certification. Also, the ISO organization does not perform the certification process. Yet, having third-party certification ensures that the manufacturer has met all requirements for the standard for medical devices. It brings peace of mind to customers that the manufacturer has gone to great lengths to ensure their processes meet quality and regulatory standards for the medical device industry.

While ISO 13485 is applied internationally, manufacturers creating medical devices for use in the European Union also must follow the regulations set forth in the EN ISO 13485. Both standards are identical as the ISO version is included in the EN ISO requirement. The only difference is that EN ISO 13485 also has requirements that align to the three EU medical device directives (EU directive 98/79/EC, EU directive 93/42/EEC and EU directive 90/385/EEC). The directives contain additional verbiage on ways to legally market and support innovation in the EU.

Learn 10 Ways to Select the Correct Connector for Your Custom Cable Assembly!

How Does ISO 13485's Quality Requirements Apply to Cable Assemblies?

The ISO 13485 requirements apply to the quality management processes that are put into place to design and create the cable assemblies. It doesn't dictate specifically how the product is designed and made. So, customers still have full control regarding the types of materials to use for the cables and how the cables are designed to keep their costs low. ISO 13485 has a set of criteria for manufacturers to follow to ensure the effectiveness of their quality management systems.

Some requirements involve the following:

  • System documentation: Manufacturers should document all quality control processes for every phase of the cable manufacturing operation. With documentation, the manufacturer can monitor that their cable products meet medical device regulatory requirements.
  • Risk management/design control: They evaluate all the risks that could be involved in creating the cables and put into place procedures to minimize these risks. If a problem does arise with the design and manufacturing of the device, the manufacturer will already have the procedures in place to determine the manufacturing issue and rectify it. In addition, this criteria also help manufacturers stay current with materials and components that may become obsolete, so they can change their design processes.
  • Manufacturing process analysis: Manufacturers will continually monitor their processes and make improvements or changes when necessary. They can perform self-audits or hire a third-party auditor to check for control gaps to quality management systems and manufacturing processes. Then the manufacture can use this analysis data in their processes.

When it comes to cables, ISO 13485 checks and monitors processes to ensure that only quality cables are created. The criteria ensure that the cables will work reliably in medical devices and will function in the appropriate manner. The standards apply to all cables, whether they are low cost or high cost components.

FDA Medical Device Classification

What are Class 1, 2, and 3 Medical Devices?

There are more than 1,700 medical devices that are classified by the FDA. Each medical device is categorized into 16 specialties under the Code of Federal Regulations (CFR). Once the device is placed in a specialty category, it then goes through premarket notification. This helps determine whether the medical device or component is risky or invasive, as it then must align to regulatory and labeling requirements. There are 3 class types that will apply to medical devices.

Class 1

Class 1 medical devices are the least invasive and offer the least risks to a person's health. Types of medical devices that that use cables and fall into this category are microscopes, AC powered dental chairs, medical examination lights, therapeutic massagers, and electric toothbrushes. The FDA's definition for a Class 1 product is: "not intended for use in supporting or sustaining life or of substantial importance in preventing impairment to human health, and they may not present a potential unreasonable risk of illness or injury." Medical devices that are in this category will have the fewest regulatory requirements.

Some devices in this category are exempt from the FDA's premarket notification requirements. Manufacturers may also seek exemptions for devices that fall within this class category. Manufacturers of Class 1 devices will still need to create and implement a quality management system.

Class 2

Class 2 medical devices have a higher risk of coming into contact with a person and their internal organs or cardiovascular system. While Class 1 medical devices fall within general controls, Class 2 medical devices will need additional manufacturing controls to be put in place to give a reasonable assurance that the medical device will operate as it is intended and will be safe to use. The FDA's definition for Class 2 medical devices is: "devices for which general controls are insufficient to provide reasonable assurance of the safety and effectiveness of the device.”

Additional manufacturing controls to bring the medical device to market include: premarket data requirements, device performance controls, guidelines, patent registries, special labeling requirements, and post market surveillance. Some examples of Class 2 medical devices that use cables include medical recirculating air cleaners, C-PAP machines, neonatal incubators, and powered wheelchairs.

Class 3

Class 3 medical devices are used to sustain and support life. They may also be implanted into a person. Only 10 percent of medical devices fall into this category, as the classification is usually reserved for the most cutting-edge equipment. The FDA's definition for Class 3 medical devices is: "devices that usually sustain or support life, are implanted or present a potential unreasonable risk of illness or injury."

Types of Class 3 medical devices that use cables include high-frequency ventilators, pacemakers, cochlear implants, defibrillators, and implanted prosthetics. Due to the higher level of safety and health risks, Premarket Approval (PMA) processes must be used as general and special controls are simply not adequate. All devices in this category must go through rigorous study to prove their effectiveness and safety. A device marketing application must be approved by the FDA.

How Medical Cables Are Categorized

Cables are categorized based on their intended use with the medical device. Some cables are non-device specific or are replacement parts, such as USB cables, so they may be used for a range of medical devices and be considered an accessory. In these instances, they may not be given an independent classification.

The FDA will evaluate the cables and determine the risk factors that the component will have and which regulatory requirements will be necessary to ensure reliability, effectiveness, and safety when used for medical purposes. This assessment will be independent from the main medical device. In addition, the accessory's risk assessment and regulatory classification can differ from the main device's regulatory classification. In these instances, differing regulatory controls may be required by the manufacturer for the specific cable.

Low Cost Cable Design Options for Medical Applications

PVC is commonly used to insulate and protect wire because it’s low-cost, readily available, and the color and stiffness can vary easily with processing. Medical grade PVC is an option as it uses specialty plasticizers (the compound that when mixed with raw and rigid PVC softens the material). Specifically, non-phthalate plasticizers are available for medical grade cables. Some of these types of cables can withstand excessive sterilization cycles making them an attractive option for one-time use and continuous application.

Medical grade PVC cables are low-cost and available in standard jacket colors like black, red, and green. The jacket can also be colorized for a custom run or to match a particular pantone color. Some medical device projects require color matching, which is possible through the use of a color ship. Although a minimum buy of any custom wire will be required, on a per foot basis the price can be very attractive. These cables are available in both single conductor format and multiconductor cross sections. Several different American wire gauge (AWG) sizes can be incorporated into the cross section.

Silicone jackets are an option in medical applications but can be both expensive and incur large minimum buys. Silicone has specialty properties that are critical for numerous medical applications. Silicone is ideal for medical applications with extreme temperatures, high-flex applications, or where biocompatible materials are required. Custom silicone jacketed cables can comply with both FDA and ISO 10993 biocompatibility standards.

Choosing Your Cable

If you are designing a product that will eventually be implanted inside the human body, or used with direct patient contact, a silicone jacket is typically required. If a silicone jacket is required, consider standard sizes and cross sections wherever possible to avoid long lead times and high costs. Can your cable be built with 3 separate conductors instead of a multiconductor cable? This could be weeks of lead time and thousands of dollars.

This decision is especially important during development and prototyping when things are always changing. PVC is a great low-cost option for any application permitted. Many PVC cables are available with low minimums and can be incorporated into samples quickly. Medical cables don’t always have to be expensive; there are options. Early and often engagement with a company like Epec is the best way to reduce risk and get to market faster.

Topics: Cable Assemblies

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