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Standards for a PSU to be considered as "SELV"

Hi - quick standards question, for hobby purposes only:


Is a declaration of being "Class II" and within the appropriate voltage band, sufficient for a PSU to be considered as SELV for usage scenarios in BS7671?


I'm doing a Raspberry Pi project with my son to PWM drive some 30V LED outdoor fairly lights. So I'm choosing a PSU that's nice and safe.


The candidate PSU I have is this one: 30V PSU (RS) or possibly this one 30V PSU (-10C) for it's lower operating temperature (it's going to be in the shed, occasional drops below 0C possible)


First one is defined as Class II, it's 30V. It also claims medical approval. A whole bunch of quoted standards on the datasheet above. Apart from "Class II", not sure if I should be looking at any particular standard that defines it as meeting SELV PSU requirements. Isolation voltage is given as 4kV?


Second one claims very little but implies Class II by lack of protective conductor pin.


Pretty sure either is a good choice (noting operating temperature limits of the first), but academically I have been curious what defines a SELV PSU if it doesn't actually have the word SELV printed on it?


Many thanks as always for letting me tap the font of knowledge that this forum is :)


Tim


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  • Hi John & Broadgage,


    Thank you both for your kind replies. Everything seems to have gone down the switched mode route these days - for green/efficiency reasons I guess...


    However, it turns out that searching for SELV 30V is a terrible search term. Better to search for LED driver on RS and work down to the right parameters.

    30V SELV Datasheet RS Product page


    30V DC, IP67, SELV, Class II, block diagram on datasheet shows full magnetic + opto isolation between input and output, over temperature/current/voltage/short circuit protections.

    Operating temperatures suitable for Siberia!


    £20


    Whilst LED drivers are not necessarily pure clean DC supplies this one is not dimmable and the ripple and output specs suggest it is proper DC out.


    The rest as always is down to trust in the manufacturer to have designed as claimed, but sourcing from RS is usually an assurance.


    Thank you for making me doubt my first choice - this one looks a lot better for the application :)


    Kind regards,


    Tim

Reply
  • Hi John & Broadgage,


    Thank you both for your kind replies. Everything seems to have gone down the switched mode route these days - for green/efficiency reasons I guess...


    However, it turns out that searching for SELV 30V is a terrible search term. Better to search for LED driver on RS and work down to the right parameters.

    30V SELV Datasheet RS Product page


    30V DC, IP67, SELV, Class II, block diagram on datasheet shows full magnetic + opto isolation between input and output, over temperature/current/voltage/short circuit protections.

    Operating temperatures suitable for Siberia!


    £20


    Whilst LED drivers are not necessarily pure clean DC supplies this one is not dimmable and the ripple and output specs suggest it is proper DC out.


    The rest as always is down to trust in the manufacturer to have designed as claimed, but sourcing from RS is usually an assurance.


    Thank you for making me doubt my first choice - this one looks a lot better for the application :)


    Kind regards,


    Tim

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