Common Differences between a UL Certified AC/DC Power Adapter and a lower cost non-UL version?

Thread Starter

Ajk Tek

Joined Jul 9, 2017
11
Hello,

I am trying to determine the common differences I can observe in a side by side comparison at the circuit board level of a UL certified AC/DC wall adapter and a physically identical model that is lower cost and non-UL certified.

For a specific hypothetical example if I were to disassemble side by side a 5v DC 2-Amp UL-Certified Adapter that company A sells for $10 next to a externally identical 5v DC 2-amp NON-UL certified adapter that Company A sells for $5, what type of differences might I see? Are their specific component quality requirements that must be in a UL certified device of this type to look for? Higher gauge wire possibly? Additional protection circuitry?

Any suggestions are appreciated.
 

dl324

Joined Mar 30, 2015
13,087
Without examples, it's difficult to say. But why would you choose to use something that wasn't UL certified for safety?
 

Papabravo

Joined Feb 24, 2006
16,778
Hello,

I am trying to determine the common differences I can observe in a side by side comparison at the circuit board level of a UL certified AC/DC wall adapter and a physically identical model that is lower cost and non-UL certified.

For a specific hypothetical example if I were to disassemble side by side a 5v DC 2-Amp UL-Certified Adapter that company A sells for $10 next to a externally identical 5v DC 2-amp NON-UL certified adapter that Company A sells for $5, what type of differences might I see? Are their specific component quality requirements that must be in a UL certified device of this type to look for? Higher gauge wire possibly? Additional protection circuitry?

Any suggestions are appreciated.
They might be indistinguishable by inspection. We often had two versions of the same product. The basic one without the cert sold for 2.5 times burdened production cost. The one with the cert cost 10 times as much because we had to keep paying the agency their monthly ransom regardless of how many we sold.
 

Thread Starter

Ajk Tek

Joined Jul 9, 2017
11
Without examples, it's difficult to say. But why would you choose to use something that wasn't UL certified for safety?
You wouldn't, that is one reason why knowing how to identify the differences in a non-certified product would be useful. Especially in cases were overseas manufacturers could label something as certified that is not. Without knowing anything to check how could one know if the item does function properly?
 

dl324

Joined Mar 30, 2015
13,087
You wouldn't, that is one reason why knowing how to identify the differences in a non-certified product would be useful. Especially in cases were overseas manufacturers could label something as certified that is not. Without knowing anything to check how could one know if the item does function properly?
You can probably find the answer to all of your questions here:
https://www.ul.com/
 

Thread Starter

Ajk Tek

Joined Jul 9, 2017
11
You can probably find the answer to all of your questions here:
https://www.ul.com/
Unfortunately I can not. I have researched there before asking, and I understand the certification testing done would be UL 60950-1, but I am unable to determine any likly visual differences that may be found in a PCB level inspection of a UL & Non-UL adapter as specified in my OP, and that is why I asked here hope for some suggestions from more experienced individuals.

Thanks anyway.
 

panic mode

Joined Oct 10, 2011
1,886
visual inspection may reveal some things (assuming details are sufficiently large, for example double insulation in transformer, grounding type, strain reliefs, potting etc.) but there is bunch of other tests that done using equipment (flammability, insulation testing etc.).

you can bet that $5 product without approval will have lousiest components.
 

AnalogKid

Joined Aug 1, 2013
9,352
Generally speaking, safety certifications for power supplies focus on keeping lethal voltages (usually power line voltage) away from the output (usually a much lower voltage), and fire prevention (the reason UL was created in the first place).

Lethal voltage and current gets to the output either through bad pc board layout and /or contamination of the board surface, or insulation breakdown. Meeting the "creepage and clearance" distance rules might increase the size of the pc board a few mm; not much extra cost, unless you are building 10,000 per week. Same for the transformer. Lower quality bobbins, thinner insulating tape, and the thickness of the varnish insulation on the coil wires all add up to pennies of savings - again times a gazillion.

Before near-universal USB port availability made individual chargers optional, the world was consuming 10 billion wall wart power supplies per year; one penny equaled 100 million dollars.

ak
 

Audioguru

Joined Dec 20, 2007
11,249
My electric utility company gave away compact fluorescent light bulbs for free to encourage reduction of electricity power consumption.
Some dripped flaming molten plastic then they were all recalled and replaced. The bad ones had a stolen certification label number.
Luckily there were no deaths.
 
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