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Topic Title: KLIK KLDS box leads above ceiling
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Created On: 09 August 2017 10:14 PM
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 09 August 2017 10:14 PM
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peteTLM

Posts: 3715
Joined: 31 March 2005

Hello,


so customer has complained about the flex leads from lights on their travels across a suspended ceiling on the way to the marshalling box.

They in their mind expect them to be strapped to the unistrut that is further up in the mess of pipes and other services, I'm arguing that they are best left loose on the ceiling otherwise they can't get the lights out for maintenance.

Views from the panel?

I have never seen flex leads from marshalling boxes restrained and fixed to the structure...

Ta

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Lack of planning on your part doesn't make it an emergency on mine....

Every man has to know his limitations- Dirty Harry
 09 August 2017 10:21 PM
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dustydazzler

Posts: 1182
Joined: 19 January 2016

You can't even see the flex unless there are tiles missing from the drop ceilings.
Unless there is copious amounts of slack on the flex leads I wouldn't tie it to anything , just put a loop in it.
If anything I dislike it when cables are tied to pipes or ducting up in the ceilings
 09 August 2017 10:49 PM
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Parsley

Posts: 1342
Joined: 04 November 2004

How long are the flexes Pete? In the good old days every fitting had a plugin rose directly above it and there were no issues with excessive flex lengths. But these days 1 or 2 multiway programmable LCMs per room may well end in longer than ideal flexes.

GN8 figure 10.8. I've not seen that on any site, but maybe Savoy House uses that method.

Regards
 10 August 2017 02:06 PM
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CMK3PD

Posts: 57
Joined: 23 September 2016

Just wondering what the impact of the 18th edition through clause:

521.10.222: Wiring systems shall be supported such that they will not be liable to premature collapse in the event of a fire.

I believe the "exit route" part of this has been removed and now covers all areas
 10 August 2017 02:13 PM
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dustydazzler

Posts: 1182
Joined: 19 January 2016

Good point, I have just this morning spoken to a someone who does a lot of shop and office fit outs.
He has now been told to secure the flex between light and klik box using metal cable ties and tie to 'anything metal' up in the ceiling.
He was recently told off for leaving the flexes loose on top of the ceiling tiles (like he has been doing for the past 25 years).
I guess with the 17th tin boards and 18th nearly upon us with the whole metal fixings thing , people are getting very twitchy
 10 August 2017 02:13 PM
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AJJewsbury

Posts: 15634
Joined: 13 August 2003

Just wondering what the impact of the 18th edition through clause:

521.10.222: Wiring systems shall be supported such that they will not be liable to premature collapse in the event of a fire.

I believe the "exit route" part of this has been removed and now covers all areas

I would have thought that as long as the flexes are relatively few, light in weight and reasonably well distributed (not great bundles weighing many kg per m) then the steel ceiling grid would be able to support their weight even during a fire (along with its own and that of the light fittings) - so that change to the regs shouldn't be a worry. AFAIK there's no change to say we can't still rest cables unclipped on suitable parts of the building fabric - just where they are clipped, the clips need to be able to withstand the fire (for a bit).

(The old worry about soft skinned cables being suitable for an environment that might contain many sharp edges and be moved around by other trades might remain though - which is where I suspect the OP's customer might be coming from)

- Andy.
 10 August 2017 02:25 PM
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dustydazzler

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Joined: 19 January 2016

not to mention , at £20 per 100 metal ties are blooming expensive compared to £3 per 100 for plastic.
so if I'm using metal ones to restrain floating cables I will be using them very sparingly , one per flex if needs must with the 18th.
or I could go all renegade and still leave loose in the ceiling like the last however many years its been done this way with no issues
 11 August 2017 04:08 AM
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leckie

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Joined: 21 November 2008

IWell surely you have to think what would actually happen in the vent of a fire? If the cable is secure before a fire, what would happen during a fire? If the cable could drop, it needs a non-combustible fixing. If it won't because it is installed in a way that it will remain where it is, then surely that's OK. It the case of the OP I would think that if the flexes are not overly long it shouldn't be a problem from that point of view. The ceiling is presumably a steel grid, if that falls down then a couple of flexes is the least of your worries. If it doesn't, the flex stays where it is.

Regarding the installation method, I think it depends on the flex length. I think if the distribution box is fixed to say basket tray, the individual flexes could be fitted into the tray and drop directly down to the fitting. I don't think the flex should be lying on the ceiling grid itself. Is there anything wrong with putting a tie onto the suspension wires that secure the ceiling to hold the cables up?
 11 August 2017 09:24 AM
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mapj1

Posts: 9107
Joined: 22 July 2004

at £20 per 100

really ?
I wonder if anyone does zinc plated mild steel ones, as S/S is overkill in many benign locations.
Hmm, I wonder... in locations like that where cosmetic appearance is secondary, and at the 'single flex' end of the game, where you don't want biting tight anyway, and magnetomotive forces during faults are irrelevant do we think we might accept something closer to a rather posh sandwich bag tie.
(I have seen these used for bits of air con drain flexi hose, so I am extrapolating it may do wires.)
twin loop tie

They do up with a tool reminiscent of the old Yankee driver but with a thing like a picture hook where the bit would be. (or by hand if you only have 6 to do, or indeed just the hook in the drill/driver with care)

more like 2p each, am I proposing sinking to a new low in cable attachments ?

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regards Mike
 11 August 2017 11:19 AM
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dustydazzler

Posts: 1182
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Sandwich bag ties ..
now you are getting the BADger spirit Mike
 11 August 2017 01:10 PM
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peteTLM

Posts: 3715
Joined: 31 March 2005

thanks all. Max run was about 6m.

After all the cables are restrained by the metal frame of the ceiling in the event of a fire, so this is just cosmetics.

-------------------------
----------------------------------------
Lack of planning on your part doesn't make it an emergency on mine....

Every man has to know his limitations- Dirty Harry
 11 August 2017 01:34 PM
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dustydazzler

Posts: 1182
Joined: 19 January 2016

6M of 'loose' flex between rose and light point is nothing in the grand scheme.
I had visions of 10-15M or snaking flex laying on top of the ceiling
Nothing to see hear , carry on
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