UL! Required if you are selling into the USA, this is a standard on safety, all require testing to make sure your product are safe, even if the testing is done in house.... And getting UL certification was interesting and quite costly.
a reply to a thread just below this that I gave yesterday...
UL is mandatory I believe and its not just a fine you will get a prison sentence...
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UK its law and UI believe the same is in the USA...
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