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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How can use this pcb header (rated voltage, nominal voltage etc.)?
I am looking at the following PCB header for a 2-piece pluggable terminal block by Phoenix GMSTBVA 2,5/ 4-G-7,62 (pdf)
However regarding voltage there are several values in the datasheet and I couldn'...
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Can we sell 110V equipment without NRTL certification in a US market?
Only in some places.
Weight scale product
certification
NRTL
110VAC
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UL ratings and power supplies (DC transformer)
I read somewhere that if you sell a product that you plan to be UL certified, this means its power supply must be UL certified as well.
This means that if you supply power via a transformer (external ...
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What assumptions are made by UL when they equate 30Vrms to 60Vdc for LVLE circuits?
UL defines Low Voltage Low Energy circuits as "A circuit involving an alternating current
voltage of not more than 30 volts, rms (42.4 volts peak) or a direct current voltage of not more than 60 ...
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Do power strips need to have a breaker?
In North America we commonly use power strips to connect equipment to the building.
https://en.wikipedia.org/wiki/Power_strip
I noticed that some power strips have a circuit breaker, and some do not.
...
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What fire tests are done on power adapters/chargers?
I was curious about the fire risks in using a typical AC-to-DC wall adapter
(e.g., this)
and went to the UL website
to learn what exact tests were done to get the "UL LISTED" stamp,
but I ...
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Product certification for NA and European market
We are developing a product that includes an already certified radio module. We even use the IC of the module as the controler of the hole device. In the device we include a RTC, a ROM, a motor ...
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What are the differences between UL1581 and UL2556 for VW-1 (Vertical Flame Test)?
In IEC62368-1, it's stated:
Wire complying with UL 2556 VW-1 is considered to comply with these
requirements.
I've asked a manufacturer if he could meet these requirements and he answered that he ...
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When does UL allow a user to access the a metal component connected to AC MAINS through a Y capacitor?
This is a 1kV SMPS design and it is considered a PRIMARY CIRCUIT by UL because it connects directly to 120V AC MAINS. It does not expose its 1kV output directly to the user, but uses the voltage ...
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Why are switchgears rated in specific capacities such as 63A, 100A, 125A and so on?
I am working in a consultant industry, wherein we get the switchgears from different OEMs. I wonder why the switchgears (including fuses and fuse-gears) and control gear assemblies are rated in the ...
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Can I import a small laundry machine from Japan for resale in the U.S that is not UL certified? [closed]
I am importing a small commercial laundry machine from Japan. It is currently not UL certified. Am I able to import this for resale in the U.S ?
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Connecting class 2 power supplies in parallel
I am looking to connect multiple rails in parallel to increase current of a class 2 power supply (UL1310). Each rail would have its own OCP (12V 8A). The problem I am having is that when talking to ...
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UL grounding requirements for equipment powered by daisy-chained connections?
I am working on a device that will have AC power in and out connectors. The intent is to facilitate wiring multiple units to the same power circuit without having to use a multi-outlet strip.
This ...
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How to guarantee clearance/creepage on mains side of an optocoupler used for 230VAC zero-crossing detection?
Update: Added a diode to protect optocoupler LED
As stated in several safety standards (UL 60950 or UL 60750 for example,) we have to guarantee a minimum clearance/creepage between signals of opposite ...
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Compliance of 2x female connectors with male pin breakaway from another brand
For a product similar to a 3D printer I'm connecting 5x small Nema 8 motors and ground cables through a small 26x connector. The connector is enclosed and cannot be accessed from the user.
The motors ...
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