On 17/12/2017 22:38, Phil Addison wrote:
My old fluorescent under-kitchen-cabinet tubes are failing at an ever faster rate, so I'm
thinking of replacing with LEDs, particularly flexible LED tapes.

A few things I'm not sure about...

The light output is quoted in lumens per metre, but how many do I need? I've seen outputs
from 290 to 780 lm/m for 12V systems and up to 1200 lm/m for 24V. The tapes will be 45cm
above a dark textured work surface. I suppose you can put 2 tapes side-by-side for a
higher output.

We tried with just one tape, and the light is very meagre compared to a
fluorescent. You'd need several, not just one or two.

A fluorescent tube is about 3000 - 4000 lumens per meter. So, you can
work out exactly how many tapes you need for equivalent light output.





The kitchen layout is U-shaped with the sink in front of a window with cabinet runs either
side. At each side of the sink the runs are finished off with a little angled/corner shelf
unit at right angles to the main run. I'd like to run the last bit of tape around this
corner if possible. Is it possible to twist it through 45 degrees or will a I have to cut
it and use a wired connector?

It doesn't bend that way. There are 90 degree connectors, but I haven't
seen 45 degree ones.


Can I just stick the bare tape to the underside of the cabinets or does it need to be
mounted into a holder such as RS Stock No. 797-2432, a horrendously expensive product!

It can just be stuck on. It doesn't get hot. However, the strip may get
dirty, particularly in a kitchen, and it would be virtually impossible
to clean. Those housings can just be wiped with a soapy cloth.


Then there's colour temperature. My fluorescents are 2700K but a lot of the white LEDs
seem to be 3000+. I don't suppose that's a big deal in this application.

What about drivers. I assume I'll just need a couple of basic 12V drivers, one each side
of the sink - though the hob interrupts the run on the right, so I'll either have to route
some cable round that of use a 3rd driver for the last cabinet which will only has a 55cm
LED run. I have easy access to the 240VAC that's feeding the 6 existing tubes. Something
like a couple of RS number 773-6949 drivers giving 1 amp each?

Any advice much appreciated, and any recommended suppliers/brands.

Phil