Get our free email newsletter

Avoiding Supply Chain Disruptions of Safety-Critical Recognized Components

Business Logistics concept, Businessman manager using tablet check and control for workers with Modern Trade warehouse logistics. Industry 4.0 concept

How a Proactive Approach Can Help Manage the Unexpected

When the COVID-19 pandemic struck in 2020, challenges arose in nearly every industry. Staffing levels were tested. Manufacturing output changed with little to no predictability. Demand for some products soared, while plummeting for others. One area severely impacted by COVID-19: global supply chains. Yet this was not the first, and certainly won’t be the last, major event to shake supply chains, where disruptions can occur for any number of reasons: natural disasters, transportation complications, cybersecurity breaches, and, of course, a pandemic.

Supply chain interruptions can lead to any number of complications. They can disrupt production and impact costs, pricing, and revenue. The potential to damage a brand’s reputation and customer/consumer relationships is also great. Yet, disruptions can happen at any time and with little or no warning. Manufacturers and product developers need to be prepared to effectively manage interruptions and their potential impact.

For most manufacturers, a preventive approach to help avoid supply chain disruptions is paramount and can be done by establishing multi-sourced suppliers to meet immediate, time- and budgetary-sensitive needs. A critical, often overlooked consideration is the identification and supply of components (including subassemblies) used in listed or certified electrical end-products. Understanding how components fit into the final product helps promote proactive supplier engagements. Knowing their application limits can also support efforts to proactively offset supply chain disruptions. And if the need to alter products arises, this knowledge will help manufacturers to make timely changes and address most certification concerns.

- Partner Content -

Why Capacitance? Benefits & Applications of Digital Capacitive Solutions

In this paper, readers will discover digital capacitive displacement measurement solutions not possible with conventional analog systems. The following applications address a wide range of industry sectors. Each example demonstrates how digital capacitive sensing systems rival the performance of more expensive and complex measurement systems at a fraction of the cost

Recognized Components

Electrical end-products have samples evaluated to applicable industry standards, then are certified as Listed by an authorized third-party certification body (CB). These products are typically ready to use from an end-user perspective, simply needing to be plugged in. Listed products often contain multiple recognized components to streamline the certification process. About 5-10% of components used in electronics are safety critical and, as such, should be recognized.

Recognized components are used within listed products that meet certain application specifications. There are countless recognized components used in electronics including wiring, switches, power supplies, relays, interlocks, display systems, lithium batteries, plastics, and printed wiring boards. Using recognized components can help streamline end-product certifications and required field inspection obligations since recognized components do not need to be reassessed, except for application-specific compatibility.

Take, for example, a power supply considered safety critical due to its voltage-isolating characteristics. A recognized power supply has been evaluated and found to meet certain requirements for safety, thereby avoiding the need for a full re-evaluation when the end-product is tested. This can save time and money by ensuring an effective certification process. Original equipment manufacturers (OEMs) should specify recognized components used in their products as well as the correct application standards that suppliers must meet to help avoid barriers to end-product certification. 

If a recognized component becomes unavailable due to supply chain disruptions, finding a replacement part and moving on with product development or manufacture may not be as simple as it first seems, because not all recognized components are created equally. 

When it comes to recognized components, there are variations in cost and the recognitions themselves. All are similarly marked and generally appear safe for their intended application. However, it is possible that some components have not gone through the same level of scrutiny to assure that all end-application considerations have been addressed, particularly since the end-product is not always known. In such cases, a product may need to be evaluated for missing considerations that often result in delay to market and higher certification costs. 

- From Our Sponsors -

Conditions of Acceptability

This potential risk can be avoided. To help ensure components fit an end-product’s certification needs, it is critical to consider Conditions of Acceptability (COAs), as well as the application needs of the end-product.

COAs can provide assurances regarding strict third-party independent safety application compatibilities of a component by establishing additional evaluation requirements at the end-product level. Returning to the example of power supplies used in computer products, a manufacturer may select a recognized power supply assembly fully tested for electrical power input rating, leakage current, and ground continuity, but not temperature or abnormal component failures, which are central to electrical shock and fire risks. The power supply’s recognized component certification report would clearly document COAs to assure the end product’s certification testing evaluates the power supply for temperature and abnormal component failure. 

COAs apply to most recognized components, almost without exception. Four commonly used safety-critical components found in electrical products illustrate the importance of COA considerations:

  • Power supplies: A thorough investigation of a power supply should include power input ratings (including leakage current), temperature,  output short-circuit protection, limited energy-availability enclosure-related accessibility protection, and abnormal component failures having fire or shock impact. Less expensive power supplies often cut costs by excluding some of these evaluations, which then results in cumbersome COA obligations and additional certification testing for an end-product utilizing the power supply. 
  • Plastics: Plastics have many characteristics depending on their end-product application use. For example, temperature, flammability rating, and thickness may not be important for plastics used for cosmetic and/or decorative purposes outside of an enclosure but are critical when used for or inside an enclosure near high-heat, power-consuming sources, typically requiring validation of the plastic’s COAs. 
  • Printed Wiring Boards: Like plastics, temperature, flammability rating, and board thickness all contribute to defining a printed wiring board’s COAs. Depending on the type and composition of the printed wiring board and safety specifics of the end product’s electrical power producing circuits, complying to the required COA can be critical and of great importance.
  • Lithium Batteries: Lithium batteries are typically evaluated for a variety of safety attributes due to their inherent risk of rupture and/or explosion if not properly designed into an end-product. Some of these considerations include temperature limits and protective considerations against inadvertent shorts and excessive currents capable of creating explosion. These include protective resister/diodes to minimize risks of overcharge and/or short circuit, depending on the enclosure and overall function of the end‑product. 

It is important for manufacturers to understand the safety-critical needs and expectations of components in relation to end-product expectations, from both a design integrity and certification perspective. Each recognized component will need to adhere to those requirements. Understanding component certification needs and COA expectations can help end-product manufacturers manage component suppliers and facilitate continued access to components, thereby assuring uninterrupted production and the ability to meet market demands.

COAs and Supply Chain Management

The best way to avoid supply chain disruptions, especially for recognized components and safety-critical parts, is to plan ahead. Truly, the best defense is a good offense. First and foremost, be sure to ask suppliers for COA lists so you can evaluate the suitability of their components in your end-product as certified. This is important not only when looking for backup, second sourced suppliers, but during the product development phase. This information, coupled with the knowledge of your product, is invaluable in your efforts to proactively avoid unanticipated issues. 

When developing a specification sheet for procuring components, always include a dedicated section covering recognized component certification requirement and expectations. This includes third-party recognized certification and markings (i.e., ETL, UL, CSA, TUV, etc.), critical requirements related to applicable standards, and specific COAs, as documented in the component’s certification report. It then becomes the supplier’s obligation to share their COAs. This helps to set expectations up front while also requiring suppliers to acknowledge and adhere to manufacturing needs. This is the time to proactively determine if there are issues from a compliance perspective in using these components in end-products. 

Thorough component specifications, including COA requirements, can also facilitate qualifying backup suppliers when and if you encounter supply chain issues. As part of the component’s certification report, the supplier should be able to provide their COAs for reference. When requirements for components are easily accessible, they can be quickly referenced during the product certification process or during the manufacture of the product. It also helps avoid the need to quickly identify and qualify backup suppliers during the product design and development phase, further leveraging your plan-ahead supplier management strategy.

Imagine, if you will, two homeowners, each with a one-story house, who want to add a second story. The first owner has the original blueprints and a builder at their disposal. The second does not. The first homeowner has information on the structural integrity of the home readily available and can more quickly and easily begin the process of adding a new story. The second homeowner needs to have additional assessments done by professionals—engineers, architects, contractors—before the second floor can be added, spending more time and money with the remodel. Manufacturers can be like the first homeowner by planning ahead and including supply chain disruption contingencies into their product design “blueprint.” 

When developing an end-product, specifications for critical safety recognized components should be considered and included in the original product assessment and certification. This will make it easier to replace and/or include any multi-sourced components when and if needed. Manufacturers can also identify anticipated replacement components when a product is initially developed, evaluated, and certified, so components are more easily swapped when necessary. Identifying backup components and including them in the original testing and certification can help avoid the additional testing (and costs) required when substitutions are made with components not included in the original certification report. 

Limited Product Certifications

Even in the best of cases, with the best intentions, it is possible to be caught off guard when the component of a listed product on the market is suddenly unavailable. Without a backup component, manufacturers may need to find a suitable replacement on short notice to continue or resume manufacturing. The use of a component not included in the original certification, especially one that is safety-critical, will require additional considerations.

Should this situation occur, the OEM first needs to find a replacement component which conforms with the COA-related requirements of the recognized component that was previously in use. Always know the standards and end-product safety application needs and familiarize yourself with COAs that apply to your product. Always request the recognized component’s COAs from the supplier to validate acceptance before submitting the end-product to a certification body for final assessment. Document COA supplier requirements and expectations in the specification sheet of the component supplier’s procurement specification.

Once an alternate component is secured, the end-product will need to be evaluated to applicable safety standards, sometimes through a simple, paperwork type of evaluation and sometimes with a more complicated review, including laboratory testing. The use of an alternate component can change the product enough that its original certification may no longer be valid without additional investigation. The good news is there is an option called a limited product certification (LPC), or single batch certification.

An LPC applies when a limited number of products are manufactured or produced at a particular factory location. An LPC involves verifying full compliance to recognized standard(s) by assessing a representative sample including a review of components and possibly testing. Because an LPC applies to a specific number of units produced over a defined time, it can be used to cover revised products against the original certification until original suppliers and/or components are restored for normal production purposes. 


Supply chain disruptions are inevitable. The coronavirus pandemic as well as several recent natural disasters have clearly demonstrated the impact that unanticipated events can have on the ability of manufacturers to produce and deliver their products and components as planned. But supplier issues do not need to tie a manufacturer’s hands in these situations. Proactively acknowledging their likelihood and planning for the worst is prudent and can make a huge difference in avoiding disruptions in the first place. Managing continued component supply allows you to pivot more quickly, and easily maintain production needs. 

Remember, not all components are created equal. Educating yourself on applicable standards, product, and component needs, and having a thorough knowledge of COAs and their importance in assuring seamless certification can reduce time and costs when the need for replacement components is required, and help secure the overall integrity and resilience of your supply chain. 

Related Articles

Digital Sponsors

Become a Sponsor

Discover new products, review technical whitepapers, read the latest compliance news, trending engineering news, and weekly recall alerts.

Get our email updates

What's New

- From Our Sponsors -

Sign up for the In Compliance Email Newsletter

Discover new products, review technical whitepapers, read the latest compliance news, trending engineering news, and weekly recall alerts.