There is always going to be some level of risk when it comes to electrical components, with the primary concerns being fire and shock. But, you can enjoy peace of mind protecting yourself, your employees, and/or your customers by adhering to power supply safety standards.
In fact, modern power supplies are carefully regulated by an array of organizations, from UL to IEC, CSA, CE, and more. There are also power supply safety precautions taken for isolation and insulation.
With all these different PSU standards, though, it can get overwhelming. What power supply do I need? Our power supply standards guide will help you navigate all the nuances at play and understand the safety concerns dealing with power supplies.
You can make sure you’re staying safe and compliant when sourcing an AC DC power supply or DC to DC converter simply by shopping here at Bravo Electro. We carry the most reputable manufacturers in the industry, like MEAN WELL, so you can rest assured you’re staying safe!
For important safety information and our full disclaimer, please click here before proceeding with any of the techniques discussed in this article.
The Most Common Safety Concerns When Dealing With Power Supplies
Before unpacking the power supply safety standards it’s important that you’re aware of the various safety concerns dealing with power supplies. These include:
- Electrical Shock: High-voltage power supplies generate dangerous current levels that can cause serious injury or death. Direct contact with live terminals, faulty wiring, or inadequate insulation are major causes of electrical shock.
- Overheating: Without adequate ventilation or cooling, PSU overheating is common and can lead to equipment failure or fire. This occurs when power supplies are installed in confined spaces without proper airflow or operate at a load beyond their rated capacity.
- Short Circuits: A direct connection between two points in an electrical circuit can lead to a sudden current surge, causing severe damage to the power supply and connected equipment - in some cases, leading to a fire.
- Incorrect Wiring: This can result in arcing, overheating, or short circuits. Miswiring power supplies can also cause immediate equipment failure.
- Inadequate Insulation: Insulation protects against electrical hazards, but it can degrade over time from wear and environmental conditions. This increases the risk of short circuits and electrical shock.
- Leakage Current: This refers to unintended current flow through the insulation or external parts of a power supply. It can pose a shock hazard, especially when sensitive equipment or personnel are involved.
Most of the time these concerns can be traced to improper handling or inadequate power supply safety precautions.
These days, there are strict power supply standards manufacturers must adhere to. Shopping with a trusted provider can help avoid many of the safety concerns dealing with power supplies.
Comprehensive Power Supply Safety Standards Breakdown
Understanding the different PSU standards makes it easier to choose the optimal solution for your specific application, keeping safety at the forefront of your decision-making. We’ll highlight the power supply safety standards below.
Class I, II, and III Standards
At their most basic level, power supplies can be classified as one of three main categories based on their electrical insulation and grounding requirements. These are:
- Class I: Basic insulation and rely on grounding for safety. These PSUs need a protective earth connection to prevent electric shock in the event of insulation failure. This standard is common in industrial applications, where the equipment's metal parts are connected to the ground to avoid the risk of shock.
- Class II: Double or reinforced insulation without requiring a grounding connection. Class II units protect users from electrical hazards with an additional layer to prevent shock even if the primary insulation fails. These are used in consumer electronics where the end-user may come into contact with the device.
- Class III: Inherently safer because the output voltage is so low that it cannot cause harmful shocks. These are typically used in devices powered by SELV (Separated Extra-Low Voltage) circuits, like in battery-powered equipment and low-voltage lighting.
We have a separate guide specifically on the class II power supply requirements if you’d like to learn more. Let’s narrow our focus to power supply safety evaluations for insulation.
The Role of PSU Insulation
Earlier we touched on how insulation safeguards against unintended contact between live electrical components and the surrounding environment or operators. But, there are two different types of insulation.
The most fundamental level of insulation provides sufficient protection against electrical shock under normal operating conditions. It may fall short for extreme conditions or potential failures, though.
That’s where reinforced or double insulation comes in. This consists of two layers of insulation as the name suggests, offering protection in case the first layer fails. This approach is often found in Class II devices and is recommended for use cases where grounding is not available.
Circuit Definitions: SELV, PELV, FELV
Those sourcing power supplies also need to be aware of differences in circuits. Here are the three different definitions:
- SELV (Separated Extra-Low Voltage): Prevents electric shock by limiting the voltage to safe levels (below 60V DC or 25V AC). SELV circuits are electrically separated from other higher-voltage circuits and don’t pose too much of a risk.
- PELV (Protective Extra-Low Voltage): While similar to SELV, these circuits may have connections to earth and could be exposed to higher voltages in some conditions. They’re used in industrial applications requiring additional safety layers.
- FELV (Functional Extra-Low Voltage): Not separated from higher voltage systems so they pose more risks than SELV or PELV. Additional protective measures are necessary when using FELV circuits to prevent accidental contact with dangerous voltages.
Creepage and Clearance Distances
These are power supply standards specific to medical power supplies, speaking to the physical spacing between various conductive components. The distance influences the risk of short circuits, breakdowns, and arcing.
Creepage distance defines the shortest path between two conductive elements along the surface of an insulating material. It must be far enough to prevent breakdown due to dust, moisture, or pollution that could accumulate on surfaces over time.
On the other hand, clearance distance is the shortest distance between two conductive elements through the air. This distance is important for preventing electrical arcing in high-voltage systems specifically.
You need to be aware of best practices for creepage and clearance to keep equipment running smoothly since PSU failure can be the difference between life or death in medical scenarios.
Leakage Current
This is another medical-specific standard. It refers to the small, unintended flow of electricity through a power supply's insulation or grounding.
While some level of leakage is normal, it can pose a serious safety risk when it becomes excessive. This concern is elevated in medical devices or environments where direct human contact with the equipment is frequent.
Regulatory standards dictate the maximum allowable leakage current for specific applications. As you can imagine, medical devices require extremely low levels to prevent injury to patients.
Power Factor Correction (PFC)
This technique improves the efficiency of power supplies by reducing the phase difference between the voltage and current. A poor power factor means that more current is needed to deliver the same amount of power, leading to inefficiencies and wasted energy.
But more importantly, as it pertains to PSU standards, proper PFC keeps you compliant with international regulations regarding energy consumption and electromagnetic interference (EMI).
There are two types, the first being passive PFC. This style uses capacitors and inductors to improve the power factor. Active PFC, on the other hand, is far more efficient. It uses electronic circuits instead and is the go-to for modern PSUs in industrial and commercial applications.
Who Oversees PSU Standards?
Now, who exactly comes up with the power supply standards? There are actually quite a few regulatory bodies you need to be familiar with. While your specific region will dictate which holds the most weight, here are some of the most common power supply safety evaluations providers.
International Electrotechnical Commission (IEC)
This globally recognized body has developed and published international power supply standards for electrical, electronic, and related technologies since 1906.
The IEC sets the foundational guidelines for electrical safety, including PSU standards. Here are a few of the most noteworthy:
- IEC 60950-1 - Information Technology Equipment: Specifically for ITE that operates below 600V. It addresses protection against electric shock, fire, and injury hazards. Computers, servers, and routers are all examples of devices that must comply with this standard. This standard has since been phased out and replaced by IEC 62368-1 as of December 2020.
- IEC 62368 - Audio/Video, Information and Communication Technology Equipment: Combines both IEC 60950-1 (for ITE) and IEC 60065 (for audio/video equipment). It’s hazard-based which means the standard seeks to identify and manage risks during the design phase. It covers both traditional and emerging technology equipment for a more flexible approach to modern product design. Smartphones, AV receivers, and home networking equipment all must adhere to IEC 62368.
- IEC 60065 - Audio/Video and Similar Electronic Apparatus: Provides guidelines for preventing electric shock and fire hazards. However, this standard is also being replaced by IEC 62368-1, which consolidates multiple safety standards under a unified framework. Still, you’ll find dated televisions, radios, and amplifiers all rated IEC 60065.
- IEC 60601-1 - Medical Electrical Equipment: As the primary safety standard for medical electrical equipment and systems it seeks to ensure patient and user safety by regulating aspects such as insulation, leakage current, and component reliability. It’s tailored to MRI machines, ventilators, and patient monitoring systems.
- IEC 60335 - Electrical/Electronic Household Appliances and Similar Applications: Covers electrical, thermal, and mechanical safety risks that can arise during normal usage or malfunction for everything from refrigerators to washing machines, microwaves, and more.
- IEC 61010-1 - Measurement, Control, and Laboratory Equipment: Devices like electrical measuring instruments, sensors, and similar laboratory equipment are all held to this standard, which seeks to ensure protection against electrical shock and hazards caused by temperature or voltage fluctuations.
It’s worth noting that new editions of the IEC power supply safety standards are constantly rolling out, so you should stay up to date on the specific requirements for the equipment used in your unique application.
Underwriters Laboratories (UL)
This independent safety science company is based in the United States and tests, certifies, and develops power supply safety evaluations.
UL’s certification is one of the most trusted marks in North America, as manufacturers must pass rigorous tests to carry the UL mark on their products. Here are a few different UL PSU standards:
- UL 1310: Applies to power supplies that limit the output to prevent risks like overheating, electrical fires, or electric shock. It’s specific to Class 2 power supplies typically used in low-voltage lighting and communication systems.
- UL 60079: Covers equipment used in environments where explosive gases are present, such as in oil refineries or chemical processing plants. These PSUs must be built in a manner that prevents ignition of hazardous gases.
- UL 62368-1: The newer standard introduced by UL for IT and audio/video equipment, replacing UL 60950-1 and following a hazard-based safety engineering approach.
You can learn more about the difference between UL listed vs UL recognized power supplies in our blog. This distinction is significant for those learning about power supply safety evaluations.
Canadian Standards Association (CSA)
Another well-established North American certification organization focused on ensuring devices meet stringent safety, performance, and environmental standards.
Like UL, CSA-certified products get put through the wringer to verify they are safe and efficient in both consumer and industrial applications. Any product sold in Canada must be CSA certified, especially in sectors like medical devices, household electronics, and industrial equipment.
The CSA mark shows that the device in question complies with CSA C22.2 No. 60950-1 and other relevant electrical standards, which means it has a reduced risk of electric shock, fire, and hazardous material exposure.
Conformité Européenne (CE)
European companies abide by their own set of standards for manufacturing electrical devices, and the CE is one example of this. This mark signifies that a product meets health, safety, and environmental protection standards established by the European Union (EU).
Power supplies specifically must meet the Low Voltage Directive (LVD) and Electromagnetic Compatibility (EMC) Directive. These are the two most noteworthy.
CE-marked power supplies are mandatory for sale within the European Economic Area (EEA), which includes all EU member states and additional associated countries.
TUV Rheinland
This global leader in independent inspection and certification services puts products through intensive testing and certification to verify they meet international standards for safety and performance.
Devices with the TUV mark have been found to meet standards like IEC 60950-1 and IEC 62368-1, covering IT and communication technology equipment.
While it’s headquartered in Cologne, Germany, the mark is recognized worldwide. It carries more weight in regions requiring compliance with both IEC and EN standards, though.
Certification Body (CB)
The Certification Body (CB) scheme is unique in that it’s governed by the IEC. The point of the CB is to provide a standardized method for certifying electrical and electronic products globally.
It requires products to be tested according to IEC safety standards, and once certified, they can be more easily recognized in other member countries.
This power supply certificaton demonstrates compliance with relevant international safety standards, ranging from IEC 60950-1 to IEC 62368-1 depending on the application. It makes things simple for manufacturers so they don’t have to re-test products in each country.
China Compulsory Certificate (CCC)
Products coming into the Chinese market must carry the CCC mark. Similar to the CE mark in Europe or the UL mark in North America, it ensures the device in question meets national Chinese PSU standards for safety.
The key areas of note are electrical safety, electromagnetic interference, and energy efficiency. Manufacturers within China must adhere to CCC as well as those seeking to export their products to China.
Power Supply Safety Precautions to Take During Installation, Replacement, and Maintenance
We’ve covered everything you need to know about power supply standards, but even the safest PSUs still pose a threat if you handle them improperly. Here are some power supply safety precautions you need to keep in mind.
Proper Grounding
Whether you’re learning how to install a new power supply or navigating power supply replacement, grounding is one of the most critical safety measures to consider.
This is important for any application but especially those involving metal enclosures or equipment. It minimizes the risk of electric shock and protects against potential surges or faults.
Always check that the grounding connection is secure and that you use a three-prong plug if necessary. This will not only direct excess electrical current safely into the earth but also stabilizes voltage levels in the system, keeping things running smoothly.
Ventilation Considerations
Make sure you give enough space around the installed PSU for heat to dissipate safely. Overheating can cut into the power supply lifespan, reduce efficiency, and in some cases, even lead to a fire hazard.
Avoid placing the power supply in confined or sealed spaces, and consider units with built-in fans or other cooling mechanisms if the environment is prone to high temperatures.
Correct Wiring Practices
Always double-check the wiring scheme to ensure the correct power supply connections between input, output, and ground terminals. Failure to do so is one of the most common causes of power supply failure and electrical accidents.
Using the wrong gauge of wire or improper connections can lead to short circuits, electrical shocks, or even system-wide failures. Follow the wiring diagram provided by the manufacturer and inspect all wiring for signs of wear or damage before use.
When in doubt, consider hiring an expert to handle the installation for you. Trust us, this is not something you want to take any chances on.
Disconnecting Power Safely
If you notice the signs of faulty power supply or LED driver failure symptoms and decide to do some power supply troubleshooting, you should first disconnect the power completely. Even a small residual current can cause electric shock.
We recommend using a lockout/tagout system as a power supply safety precaution, especially in industrial environments. This will prevent accidental reconnection while you’re working.
Further to that point, always wait for any capacitors to discharge fully before handling the power supply, as these can store dangerous levels of voltage even after the power is turned off.
Testing and Monitoring
Attempting to fix power supply malfunctions is possible, but you need to make sure you are testing the PSU after the fact to verify it’s operating safely and within specified parameters.
Use a multimeter to check for proper voltage output, current levels, and grounding continuity. Monitoring power supplies for abnormal behavior, such as unexpected noise, excessive heat, or inconsistent power delivery, can help identify issues early before they lead to larger failures.
You may even want to invest in automated monitoring systems for real-time tracking of voltage, current, and temperature in your most critical applications. This empowers you to act fast in the event of an issue.
Our blog has more resources on topics like power supply specs, advantage of having a redundant power supply, how to check PSU wattage, DC DC converter efficiency, power supply topologies, and more.
At this point, though, it’s time we wrapped up our power supply safety standards guide with a few closing thoughts below.
Wrapping Up Our Power Supply Safety Evaluations Guide
Hopefully, this power supply safety standards guide has left you with a clear, confident understanding of the role each organization plays and its specific standards.
You’re also aware of the safety concerns dealing with power supplies so you can protect yourself and others during installation, operation, maintenance, and replacement. Don’t overlook the power supply safety precautions we shared above.
The only thing left to do now is source any of the different types of power supply you could need, be it a linear vs switching power supply, low profile power supply, the best modular power supply, or anything in between.
Bravo Electro sources from only the most well-respected power supply manufacturers in the industry and we have solutions tailored to the exact power supply standards you need. Our most popular categories include:
You can also filter your search by power supply voltage, whether you need a 12 volt power supply, 24 volt power supply, or 48 volt power supply.
Better yet, get in touch with our customer service team. We can guide you towards the optimal solution to help you avoid guesswork and uncertainty. We can even make custom power supplies! So, shop now or reach out to enjoy peace of mind meeting any PSU standards.
