Kitchen Lighting

[Peter]

I guess much of this has been answered previously, so apologies for any duplication.

We're just getting round to rebuilding the kitchen, back to bare brick mostly and rafters exposed. Although now at the insulation / plasterboard stage so need to plan the wiring. 

The room is effectively split in two, one half has a pitched roof and the other is part of the ground floor of a two storey house - flat ceiling.

The ceiling / joists of the pitched roof have been removed to open up what was the loft space into a vaulted roof area. This will be squared off, about 1m below the apex of the roof and I think will have a LED strip to avoid deep shadows (especially in the evening). 

This part of the kitchen will have floor units along its perimeter (no wall units). I think two banks of 24V LED spots to illuminate the work top areas. 

A 3m island will extend down the centre line of the room - 240v lights on long flex to illuminate the island. These will be wired back to a 240v dimmer in the enclosure. As this end of the kitchen will be for seating and not working, I don't think any additional lighting will be required.

Island and perimeter floor unit plinths to have 24v LED strips.

So, I'm happy with the 240v lighting but not sure how best to power the rest. I've read a number of posts where power supplies are positioned under units, presumably connected to a 240v ring main? I also assume that the DMX dimmers are also co-located with the power supplies? I can't for the life of me figure out how a 24v power supply can be located in a completely different place to the dimmer. Perhaps I'm missing something? (For the upstairs lighting I have located power supplies and the dimmers in the loft with a CAT cable back to the Dimmer extension in the Enclosure).

Whilst I know I can buy small power supplies which can be pushed back into a ceiling void for the spots, a dimmer may be a different proposition. I also wonder if I should power the spots from a separate circuit to the kitchen ring main?

[David Wallis]

You could connect the psu as you say to a FCU on a ring main (from this I'm assuming UK :) )

When you say DMX dimmers, does that mean you are using DMX? if so then you would need to run a twisted pair cable from your dmx ext. to the individual dimmers and wherever they sit in a bus and then add a terminator at the end, similar to the CAN bus (loxone link) 

24v psu can easily be located as a seperate place to the dimmer.. its no different to the lights and psu being in seperate places...

Do you have a route available back to your panel, if so I would keep everything combined and just run 5 core for led strip and appropriate sized cables for the 24v lighting.. (that would be my thoughts.) otherwise you are into hiding dimx extensions/ psus etc in the back of kitchen cupboards.. You could mount them under - behind the plinth - but thats down to interpretation of the regulations requirements for "accessible"

Plenty of options, just depends what works for you.

[Duncan]

options:

24v psu and dimmers in control panel, away from led strips

good - central location, easy to access

bad - long 5 core cable runs to leds (need to be thick to take current)

24v psu in control panel, dimmers under cabinets behind plinths directly next to leds

good - power supplies easy to get to, connection from dimmers to leds short, easy to manage, may only need tails already on led strips to reach dimmers

bad - 24v cable will have to be ok for current, but at least you only need 2 cores

24v psu and dimmers under cabinets

good - all cables short, easy wiring

bad - need 24v socket in back of a cabinets so you can isolate, needs dmx control cable, need to remove plinths to get access (but this isnt too difficult)

[RSinn]

I'd just add that if you put the dimmers and PSU centrally I would cost up the cabling. Running 5-core is easier but more costly than running 2 lots of t&e. Also if you are only running warm white or single colour you don't need 5-core, that's just for RGBW led strip.

Also if you have a lot of 24v dimmers it is more cost effective to buy a big one with lots of channels (Ltech 932 has 32 channels) than lots of dimmers for individual led strips. But then you have to mount it all centrally.

[Peter]

Thank you for the replies. Really useful and I’m especially taken by the idea of using a 32 channel decoder, which is so much cheaper than using Loxone dimmers. Presumably DC1, DC2 etc will require their own power supply?