On 4/4/2021 1:00 PM, Cydrome Leader wrote:
> Peter W. <
peterw...@gmail.com> wrote:
>> Guess I should put them up on my web site...but they will
>>> be more than $1 as I think these are actually UL/CSA approved.
>>
>> John:
>>
>> As these would never be stand-alone devices, they should carry a UR (with the R reversed) designation. And, yes, that would be handy.
Start with UR. Run the letters together. Mirror image it left-right.
Slant it like a back italic.
>>
>> Peter Wieck
>> Melrose Park, PA
>
> Anybody know the history of that symbol? It's cool looking, and seems to
> be something beyond what UL would ever come up with on their own.
>
UR is a UL recognized component. They are tested to a UL standard, but
to use the component in a UL listed device UL has to clear it for that
device or class of devices. That may include conditions for its use.