UL 60950-1 vs UL 62368-1: Which Standard Applies to Your New Power Supply?

Does the product category define the applicable standard

The first step in choosing the right UL standard is identifying what the power supply is actually powering. The standard is not chosen based on the voltage rating or the enclosure material. It is determined by the intended use of the equipment.

If the power supply feeds a general purpose audio or video device, UL 60950-1 is often the reference standard. This applies to devices like home stereos, televisions, and older computer systems. If the power supply feeds information technology equipment, such as servers, network switches, or desktop PCs, UL 62368-1 is the current reference.

This distinction matters because the testing protocols differ. The safety features required for a server room are different from those required for a home entertainment center. A power supply designed for a rack-mounted server must meet different mechanical and electrical requirements than one designed for a consumer TV.

What changed when UL 60950-1 became obsolete

UL 60950-1 was the long-standing standard for audio, video, and information technology equipment. For years, this standard dominated the market for power supplies. It covered everything from small audio amps to large computer power units.

The standard was eventually withdrawn and replaced by UL 62368-1. This transition did not happen overnight. There was a period where both standards were in use simultaneously. During this overlap, manufacturers had to decide which standard to follow based on their product roadmap and customer requirements.

The new standard introduced a different risk assessment approach. It moves away from a fixed list of test cases and uses a risk-based evaluation. This allows for more flexibility in design. It also places greater emphasis on the overall system rather than just the power unit itself.

Many buyers still see UL 60950-1 on older equipment. This is normal. It does not mean the equipment is unsafe. It simply means the product was certified under the previous standard. New designs should generally follow the current standard unless there is a specific reason to use the older one.

How to check which standard your power supply requires

Start by looking at the nameplate or the datasheet provided by the manufacturer. The nameplate will usually list the applicable standards. If the plate says UL 60950-1, that is the standard that was used for certification. If it says UL 62368-1, that is the current standard.

If you are designing a new power supply, you need to define the product category in your design specification. Is it for IT equipment? Is it for general purpose audio or video? This definition drives the testing scope.

The testing laboratory you choose will ask for this information. They will not guess. If you provide incomplete information, they will ask for clarification. This causes delays. A clear product definition prevents these back-and-forth exchanges.

Also check the original equipment manufacturer’s documentation. If the power supply is an accessory for a specific system, that system’s manual will state the required safety standard. For example, a server vendor will specify which UL standard their power supplies must meet.

What testing differences matter for power supply buyers

The physical tests differ between the two standards. Both require electrical insulation checks and mechanical stability tests. However, the specific test methods and acceptance criteria can vary.

For UL 62368-1, the focus is on the risk assessment of the entire equipment. The power supply is part of a larger system. The lab evaluates how the power supply interacts with the host device. For example, if the power supply feeds a network switch, the lab looks at the risks associated with that specific combination.

For UL 60950-1, the testing is more prescriptive. It follows a fixed list of tests. This can be easier to plan for, but it offers less flexibility. The lab does not look at the context as much. It looks at the unit in isolation.

These differences affect the cost and time of certification. A risk-based assessment can be faster if the design is straightforward. A prescriptive assessment can be slower if the design has unusual features. Always confirm the testing scope with the lab before finalizing the design.

How to avoid compliance delays during the certification process

The most common cause of delays is picking the wrong standard. If you send a design for testing under the wrong standard, the lab will reject it. You then have to re-submit the design. This wastes time and money.

To avoid this, create a simple checklist before sending the design to the lab.

1. Identify the product category. Is it IT equipment, general purpose audio/video, or consumer audio/video?
2. Check the manufacturer’s datasheet for the listed standard.
3. Confirm the intended market. Some regions have different requirements.
4. Verify the power supply’s voltage and current ratings.
5. Provide a clear description of the host equipment.

A lab will reject a submission if the product description is vague. For example, saying “computer power supply” is not enough. You need to specify the type of computer and the intended use. A server power supply is different from a desktop power supply.

Also, ensure that all documentation is complete. The lab needs the design drawings, the bill of materials, and the test report from the previous step. Missing documents cause the lab to pause the process. This delays the final certification.

How to compare quotes from testing laboratories

When you request a quote from a testing lab, ask which standard they will use. Do not assume they will pick the right one. State your requirement clearly in the RFQ.

The quote should list the specific tests that will be performed. Look for any hidden costs. For example, some labs charge extra for expedited service. Others charge for additional test samples.

The table below shows the main factors that affect the cost and time of certification.

Cost Driver	Description	Impact on Budget
Product Category	IT equipment vs. general purpose audio/video	Determines the standard and test scope
Complexity	Number of power supplies and host devices	More devices means more tests
Expedited Service	Faster turnaround time	Higher cost for urgent projects
Additional Samples	Extra units required for testing	Increases sample costs
Documentation	Completeness of design files	Incomplete files cause delays and rework

The lab will provide a timeline based on your request. Compare the timelines from different labs. A shorter timeline is not always better. It may mean fewer tests are performed. Always review the scope of work before signing the contract.

If you are unsure which standard applies, ask the lab for a preliminary review. They can look at your design and tell you which standard is appropriate. This costs a small fee but saves a lot of time in the long run.

What to do if your power supply is already certified under the old standard

If you have a power supply that is already certified under UL 60950-1, you do not need to re-certify it immediately. The certification remains valid as long as the design does not change.

However, if you make a significant change to the power supply, you may need to re-certify. A significant change is one that affects the safety of the product. For example, changing the enclosure material or the voltage rating.

If you are adding a power supply to a new product, check the product’s required standard. If the new product requires UL 62368-1, the power supply may need to be re-certified under the new standard. This depends on how the power supply is integrated into the product.

In some cases, the lab can accept a partial re-certification. This means they only test the parts that changed. This is faster and cheaper than a full re-certification. Ask the lab about this option.

It is also possible that the power supply can be used as is if the host product is certified under the old standard. This is not common for new products, but it can happen. Always check with the lab and the host product manufacturer.

How to document your standard selection for future reference

Keep a record of which standard you chose and why. This document should be part of your design file. It should include the product category, the intended use, and the lab’s confirmation.

This document is useful for future audits. If a customer asks which standard your power supply meets, you can provide the documentation. It also helps when you update the product. If you change the product, you can refer to the original decision to see if a re-certification is needed.

Create a simple table in your documentation. List the power supply model, the host product, the standard used, and the date of certification. This table should be updated whenever a new model is released.

This practice saves time and prevents errors. It also helps when you are comparing quotes from different labs. You can see which standard was used for previous models and apply the same logic to new ones.