On 18/12/2017 12:36, John Rumm wrote:
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.
I went with the LEDHut 72W/5m strip, and that to me seemed just right.
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 will be tricky to change angle in that plane and keep it flat. Cut
and wire would give a neater result.
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!
I left it bare since you can't see it. If you want there are splash
proof and fully waterproof versions if you are worried about water /
steam etc.
You can also get :
https://www.ledhut.co.uk/led-strip-l...es-bundle.html
(go to the trade version of the site for better prices!)
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.
Probably not - kitchens can get away with "whiter" light IME. However
the 2700K tape works well.
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.
On mine I went with something like:
https://www.ledhut.co.uk/led-strip-l...er-driver.html
and actually mounted it *inside* the cooker hood, and powered it from
its internal lighting switch. So when you switch on the cooker hood
light, it also brings on the under cabinet light.
Would you normally buy stuff where it says:-
"20% of the transformer capacity needs to be left over to prevent
overloading "?
Why are they quoting load figures that are unsafe if you use them?
Is it even an isolated supply or just some cheap Chinese SMPSU?
For damp areas you really want an isolated supply to avoid shocks and/or
RCD trips.
You should consider something like
http://cpc.farnell.com/powerpax/led-...15w/dp/PW04025
Which is a SELV led driver and is isolating, runs at 100% of its rating
(and is cheaper).