SELV Power Supplies and Equivalents
Whilst the lighting standard EN 60598 specifically states that an SELV transformer is required, this specification of transformer is now little used in domestic, IT and office equipment standards, so there is not a wide choice of SELV transformers available. But we can argue for an equivalent standard.
Standard EN 60950-1 is the standard for IT and general domestic and office electronics etc., and it specifies an SELV transformer. However it has since been replaces by EN 60238-1, which redefines a safe transformer, and dispenses with the SELV term. The good thing is that Annex W of 60238-1 states that an SELV power supply is equivalent to an ES1 power supply to 60238-1 in terms of safety (ES1 basically denotes that the item is intended for use by anyone, not a technician or an engineer - all external power supplies to 60238-1 will be to this level of protection). Thus I'd argue that in designing a lamp, it is perfectly acceptable to use an external power supply to EN 60238-1, which means that you have a vast range of power supplies to choose from.
Mains to 12V SELV Power Supplies
This section looks at sources of SELV power supplies.
There are a few makers of stand-alone 12V power supplies that can be use external to the lamp:
- Leyton Lighting https://www.leyton-lighting.co.uk/t/categories/drivers-and-controllers
- Bright Green Connect https://brightgreenconnect.com/product_cat/constant-voltage/
There are many makers of LED drivers designed to be mounted in the lamp (which negates the benefits of lower regulatory requirements), or in a cupboard or ceiling space in a house.
For both of the above, they want to be fixed voltage drivers, not fixed current.
For house installations, there are mains to 12V SELV transformers primarily designed for use in wet areas like over the shower, where the light or fan has to be low voltage with an SELV transformer outside of the wet zone.
For outdoor use, there are several manufacturers of mains to 12V SELV power supplies for outdoor lighting, often using things like waterproof cable glands.