Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [ul]

UL (Underwriters Laboratories) is a global independent company that performs safety consulting and certification. They publish many safety standards for electrical and electronic products and the UL mark on equipment indicates it has passed their tests for electrical safety.

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Electronics System Standards Compliance: Certification, Testing & Verification

Please note: this question has to do with the technical compliance aspects of the consumer electronics indsutry, and as such, I believe is within scope for this site. This question is about compliance, and Compliance is absolutely a qualitative…
smeeb
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Is UL approval required on all items sold in the USA

I have a spray tan machine which I wish to sell in the USA. I have had the machine tested by a CE test house. Do I have to have a UL approval as well?
user3143
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What is the nature and history of UL capacitor recognition?

First, the background. I've been working on a grid-tied inverter design for some time now. General topology is: We've just completed UL listing our product under 508c, and the process was quite instructive. UL performs "breakdown of components"…
Stephen Collings
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Is it safe to use a DC power adapter that isn't UL Listed or CSA certified?

I picked up a 9V switching DC adapter from SparkFun a while back, but I've been hesitant to use it because it doesn't have any of the usual "safety" approvals that you normally see on power adapters (UL listed, CSA approved, etc.) Is this just…
Owen Thomas
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Transient voltage suppression diode not doing its job

I have a circuit which works on 21V DC and draws 3A maximum current. I need to get it tested to IEC 61000-4-4 and 61000-4-5 standards which are surge immunity tests. I use a UL certified switch mode power supply to power my unit. The supply…
mic
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How to get UL approval for lamps and pendants

I'm a glass artist and designer and would like to make lamps and pendants. I'm told that I need UL approval for the electrical part. That is all the wiring etc. I know I can have an electrician who can do that part but I'm concerned about the…
varda
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Why only 500VAC rating for this Y-capacitor?

I’ve been looking through a reference designs for an off-line flyback converters (this one by Texas Instruments and this one by Linear Technology). Both of them have a Y-capacitor between primary and secondary for EMI suppression. Like this, for…
Nick Alexeev
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Do you need to UL Certified the enclosure with the board inside?

I want to use the RaspberryPI in an industrial environment that requires all devices have UL certification. The RaspberryPI board has UL certification but there is currently no enclosures that are certified. I have been told the UL certification…
Steven Smethurst
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High dielectric strength temperature sensor (2500V)

I am trying to measure the temperature on a heatsink that is at Earth ground potential, while my circuit ground is at line potential. Typically I would use something like the Microchip MCP9700 in a TO-92 package, but there is seemingly no way this…
Daniel
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How do variable-frequency drives pass UL 508c failure of components testing?

Every 480V variable frequency drive I've had the pleasure of dissecting has had two DC capacitors in series across its DC bus, each rated for ~400VDC. UL 508c testing as executed on one of my recent products requires that all components whose…
Stephen Collings
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Bringing compiled device to market (and how to power)

(Preemptive apology if this is the wrong place to ask; pointers to the right place appreciated) I've thrown together a device using a Raspberry-pi, touchscreen (plugs into pi) and small monitor type thing which has its own power cord and brick.…
canterman
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What is this mains blade connector called?

I've asked around and can't find answers anywhere. I'm designing a PCB that connects to US-style mains blade connectors (that plug into the wall). I've found these here, but I need right angle connectors as the board is at a right angle to the wall.…
user3666672
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Circuit Testing, Verification & Certification Standards for Biomedical Devices

Please note: I would have posted this question on HealthIT.SE but they are apparently now closed for business, and I believe this site is the next most appropriate place to ask this. I believe this question is on topic because it involves circuit…
smeeb
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If I incorporate a UL/NRTL listed power supply in our product, must we re-test?

We are building a product. It's a bench-top electrical testing thing, similar to a Keithley DMM or an oscilloscope in that it's something engineers would use at companies for testing stuff and occasionally would get built into other equipment. I…
Dave
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Are power supplies for USB drive enclosures required to have UL certification?

I bought a cheap USB hard drive enclosure off eBay. It turns out that the power supply has absolutely no electrical certifications for either the US or EU (no UL, CE marks). Is electrical certification required for these power adapters (that come…
Anon
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