Ceiling design for 600x600mm LED drop-in panels please.

[Mark42]

In principle it looks and sounds fine. Depending on what work is being done in there. For instance if colour is important you might want to consider higher CRI factor. It sounds like you will be doing officey things in there? If so you need to get lights which have a UGR of 19. You need to know in advance the lumens deliver to desks, assuming there will be desks from your descriptions. The one big factor you need to work out is what is the inrush current. That amount of lights will struggle not to blow the MCB due to inrush. You might need to split them up circuit wise. You do not seem to mention emergency lighting or anti panic (required in a room that size. Just a few thought for starters. By the way I do a lot of commercial LED retro fit and upgrades. Oh and I don't personally like the asymetric nature of the layout.

The perception of colour is unimportant.

Most of the work which matters will be scientific research type stuff, with people and machines. A desk or two for recording research results, but mainly people milling about.

Good point about inrush. These fittings from TLC are soft start so I'm guessing a 3P B6 MCB will be fine. Each of the three circuits would be on a separate phase anyway.

A few fittings will have emergency back up batteries. I didn't mention that for clarity.

I've never heard of 'anti-panic' ... My industry mitigates that risk not by engineering contols, but by excluding the kind of people prone to panic

Good points about glare. I have bought one 5000K panel, and it looks OK - very evenly lit - unlike the point-source retina-busting nature of many LED fittings. Despite that I've now changed to spec to 4000K panels.

One guy did complain last week in another workshop about the unnatural quality of the light from my metal halides. But he was a techie physicist dude much given to speculation on the psychological effect of discontinuous spectra, so I ignored him. ?

You and Telectrix have caused me to have a rethink. Thanks! Here's a new plan:



I'm slightly concerned that this might not be bright enough. It's theoretically 610 lux with all on, but it is a high ceiling at 3m: the inverse square law is a bugger.

This new design allows for the easy addition of another 13 panels on the red circuit at the red X positions if needed.

I'd originally used so many fittings, together with the weird asymmetric arrangement, so that any one circuit on alone would not be too patchy.

Cheers, Mark.

 

[Vortigern]

Are you sure about the lumen output on Yel and Blue? Anti panic is a description of the function of the emergency lights. i.e. there will be some light when all the lights go out instead of darkness. UGR must be specifically specified when purchasing the lights. They are a specific class of lights. You can ask the manufacturer if the lumen/Lx delivery will meet requirements in the environment you propose to provide lighting for. You can also ask them the inrush current characteristics of their lights. At the same time you can obtain the photometric date for the lights as well as for the emergency light fittings. In getting the photometric data you can prove, in the absence of a luxmeter, that the emergency/anti panic deliver the required lumens as specified by BS standards (5266). As well it is usual to supply circuits in 10a for commercial. Not entirely sure why that is, but of course not compulsory. Are you planning to use white 20mm conduit and Klix fittings for the install? And the new design looks a lot better by the way. What are the red crosses?

 

[DefyG]

Are you (OP) trying to raise the lighting level for the whole area for detailed/inspection work or just specific areas?
We did a similar job couple years back where the overall/general level of lighting was high (>500lm) and just specific areas (Panels side by side) to raise level (>800lm) where detailed work was required.
Arrangement looks odd on paper but worked in practice - It was a small photographic/print works FYI.

 

[telectrix]

The perception of colour is unimportant.

Most of the work which matters will be scientific research type stuff, with people and machines. A desk or two for recording research results, but mainly people milling about.

Good point about inrush. These fittings from TLC are soft start so I'm guessing a 3P B6 MCB will be fine. Each of the three circuits would be on a separate phase anyway.

A few fittings will have emergency back up batteries. I didn't mention that for clarity.

I've never heard of 'anti-panic' ... My industry mitigates that risk not by engineering contols, but by excluding the kind of people prone to panic

Good points about glare. I have bought one 5000K panel, and it looks OK - very evenly lit - unlike the point-source retina-busting nature of many LED fittings. Despite that I've now changed to spec to 4000K panels.

One guy did complain last week in another workshop about the unnatural quality of the light from my metal halides. But he was a techie physicist dude much given to speculation on the psychological effect of discontinuous spectra, so I ignored him. ?

You and Telectrix have caused me to have a rethink. Thanks! Here's a new plan:

View attachment 63304

I'm slightly concerned that this might not be bright enough. It's theoretically 610 lux with all on, but it is a high ceiling at 3m: the inverse square law is a bugger.

This new design allows for the easy addition of another 13 panels on the red circuit at the red X positions if needed.

I'd originally used so many fittings, together with the weird asymmetric arrangement, so that any one circuit on alone would not be too patchy.

Cheers, Mark.

that looks better to me, but should be more on red circuit, less on yellow and blue. and i would opt for 10A C curve MCBs on all 3.

 

[Mark42]

Are you (OP) trying to raise the lighting level for the whole area for detailed/inspection work or just specific areas?
We did a similar job couple years back where the overall/general level of lighting was high (>500lm) and just specific areas (Panels side by side) to raise level (>800lm) where detailed work was required.
Arrangement looks odd on paper but worked in practice - It was a small photographic/print works FYI.

Because no two jobs/rentals are the same I don't have the luxury of being able to install overall/task/accent lighting in fixed places. So I'm trying to go for two fixed levels (say 'normal' and 'bright') for the whole area.

 

[Mark42]

that looks better to me, but should be more on red circuit, less on yellow and blue. and i would opt for 10A C curve MCBs on all 3.

As there are now so few fittings compared to my first proposal, I downgraded the third smaller circuit, which was only ever for dim overall lighting when popping in to get something. But I'll do as you suggest and change a few. See below ...

If I reduce the number of either 'yellow' or 'blue' panels in the new reduced design too much, there won't be enough left to be used alone to light the whole room, when high intensity task lighting is not needed. Hence the odd unbalanced design.

There's a further complexity which I didn't mention: the L2 circuit has a 'security lighting' relay across the switch. This is standard throughout all the buildings, all of which are interconnected with a 25-pr data cable, one pair of which carries +24Vdc from the alarm panel in case of an alarm activation. (Via a Texecom relay output). The effect is to blast every building, and a lot of the grounds, in light in case of an alarm, or if any panic button is pressed. So I need to be sure the L2 circuit has enough lights to frighten off, and to get a clear CCTv picture of any low life who breaks in thinking he'll find a quad bike to nick.

There's also the consideration that, for historic reasons, L1 and L2 have a solar supply, but L3 is paid-for only! This was all too much detail for my original questions.

And there's a technical reason why I want to at least try a 6A B-curve MCB first: I have a spare one in my box! ? If it trips, I'll do as you suggest and buy a new 10A.

 

[Mark42]

Are you sure about the lumen output on Yel and Blue? Anti panic is a description of the function of the emergency lights. i.e. there will be some light when all the lights go out instead of darkness. UGR must be specifically specified when purchasing the lights. They are a specific class of lights. You can ask the manufacturer if the lumen/Lx delivery will meet requirements in the environment you propose to provide lighting for. You can also ask them the inrush current characteristics of their lights. At the same time you can obtain the photometric date for the lights as well as for the emergency light fittings. In getting the photometric data you can prove, in the absence of a luxmeter, that the emergency/anti panic deliver the required lumens as specified by BS standards (5266). As well it is usual to supply circuits in 10a for commercial. Not entirely sure why that is, but of course not compulsory. Are you planning to use white 20mm conduit and Klix fittings for the install? And the new design looks a lot better by the way. What are the red crosses?

Thanks. I already got the photometric data from the TLC site, everything else I'll decide by trial-and-error! These appear to be very evenly-lit panels, glare-free, with a 120 degree output angle.

No conduit, no. These are inset panels designed for a drop grid ceiling so all wiring goes in the void. I was intending to use T&E between Wago boxes. The panels come with drivers with short pre-wired tails, so that struck me as the easiest way. A single and earth provides the power failure signal for the emergency units. All wiring cable-tied along the grid. Is there a better, perhaps more modern way? The roof above is sprayed with horrible foam, so I can't get any neat conduit up there.

The red crosses are potential points to augment with more panels if the room's not bright enough!

 

[telectrix]

I was intending to use T&E between Wago boxes.

ow are youplanning on supporting the T/E? hope you're not intending to just lay it on the false ceiling.

 

[DefyG]

Is there a better, perhaps more modern way?

Maybe 'lighting distribution boxes' but if 'short' flex's from panel drivers do not reach then could become a more costly install.
Still need a supply to each box and I guess you are implying cable tying to the straining wires??

 

[Vortigern]

All wiring cable-tied along the grid. Is there a better, perhaps more modern way?

Not only modern but time honoured quality installation, conduit 25mm and Klix connections every time for me. None of that cables on the tiles/in the void very poor technique in my opinion. Besides if you plan the Klix points properly you can move and add lights with ease. With the void wiring when you want to rejig things you start ending up looking like spaghetti junction up there and it is confusing when you want to change lighting/switching, don't do it!

 

[Mark42]

Not only modern but time honoured quality installation, conduit 25mm and Klix connections every time for me. None of that cables on the tiles/in the void very poor technique in my opinion. Besides if you plan the Klix points properly you can move and add lights with ease. With the void wiring when you want to rejig things you start ending up looking like spaghetti junction up there and it is confusing when you want to change lighting/switching, don't do it!

I don’t disagree. But to what do you fix all that beautiful neat conduit? (Assuming you do of course mean rigid PVC)

The internal roof structure is covered in 200mm of messy foam.

The drop ceiling meets the walls at the eaves, so there’s no room there either.

 

[Vortigern]

You fix them to the same thing you are going to fix the suspended ceiling to, non? At least you could use marshalling boxes?

 

[Mark42]

You fix them to the same thing you are going to fix the suspended ceiling to, non? At least you could use marshalling boxes?

Here are some pictures of today's work-in-progress.

Note the horrible foam insulation. I'm fixing the ceiling grid wires by making small holes in the foam, finding the metal purlins, fixing brackets with Tekscrews, then filling the hole with a foam gun. Only the small office is done so far. There are a couple of trial LED panels in there: one 30W the other 40W.

There's no way I can think of to get neat conduit up in that roof. Hence my proposed bodgers' delight method of running cables along the grid. I may use Flexishield, or run T&E in flexible 20mm (TLC have good deals on 20mm flexi, I use it a lot.)

What would others do, given the job of wiring a shed-load of light panels in this suspended ceiling?

 

[GBDamo]

Tray hung on threaded rod from the purlins right down the centre.

Cables on the tray, marshaling boxes fixed to the underside.

 

[Mark42]

Tray hung on threaded rod from the purlins right down the centre.

Cables on the tray, marshaling boxes fixed to the underside.

The flange on the purlins is very flimsy, and not horizontal, but it could be done, so long as any lock nuts are not fully tightened, to allow the studding to hang vertically.

BUT ... How would I then get individual cables from the minimum 23 panels to the marshalling boxes? Might that not be more of a rat's nest that runnning the three supply cables directly as single radials looped to each fitting at ceiling level?