suspended ceilings

[crabapple]

when wiring lighting for suspended ceiling, is i ok to just chuck the cable over the top or does some other measure have to be taken(i mean i could use baskets, but on slim budget)

 

[Des 56]

Slim budget solution for cable over suspended ceiling
or otherwise called

12mm All Round Band - Quantity 10 metres - On-Demand Supplies

 

[Darkwood]

Cables are not to be laid across the suspended ceiling but if on a budget you can just hang loops from original ceiling to run all your cables in (grouping factors in mind), insulated allround band is usually the quickest method, but all depends n the job/contract to the way you suspend your cables this method wouldn't be appropriate on a new build complex where tray or basket may be requested.
To my mind their is only one cable that has been granted as an exception to the rule and its supplied with the automated thorlux fittings to loop the fittings together (plug and socket kits) this flex has been designed to resist the sharp edges etc of the grid without adding a weight issue to the grid.

 

[crabapple]

so i defo have to use band and ties

(always have in the past)

i was told nver to leaave cable to suspended ceiling, but seeing many a job thought i was just being overzealous

 

[grantr37]

should really be in conduit then onto short run basket, or if mcurdy boxes should be conduit to mcurdy then the flex to the back of the fitting...

 

[Darkwood]

dont think it was brought in until the 16th regs, before that it was common practice to run them over the ceiling, even did it myself in my early yrs mg_smile: but more so to do with the lax methods the company i was with.

 

[kingeri]

What about in domestic, on a normal plasterboard ceiling? It's common to find cables laying on top of the ceiling, and also junction boxes.

 

[Darkwood]

should really be in conduit then onto short run basket, or if mcurdy boxes should be conduit to mcurdy then the flex to the back of the fitting...

You say 'should be' but provide no ref' regulation to confirm this, as far as reg's goes they are not to be run across grid ceilings, the method you choose to achieve this is at your own discretion, will agree you method you suggest adds that pro' finish but when money is on a shoe-string their is nothing wrong with just running the cables around in a 'all round band' loop system.

 

[Darkwood]

What about in domestic, on a normal plasterboard ceiling? It's common to find cables laying on top of the ceiling, and also junction boxes.

This thread is about Ceiling Grids which are metal, unearthed and sharp edges and pose extra hazards, you domestic situe is common to find and the risks associated are minimal, if someone was to screw up through the plasterboard it would normally be into a joist anyway.

 

[timbobelfast]

Generally in a domestic environment cables are clipped along joists or drilled through them.

 

[Amp David]

Last small office i did, had conduit run around the perimeter above the suspended ceiling, then used Klik roses off conduit boxes out to each fitting.

Also another small budget, hence why supporting basket or similar from the main roof of the unit. The office was on a mezanene floor

 

[Mark_Burgess]

To keep cable off the grid, you could use these types of clips.

 

[Philpot]

There was recently an inquest into the tragic death of two fire fighters in Shirley Towers Southampton. One of the contributing factors was cables hanging down from a suspended ceiling after it collapsed. There were calls for the cables to be secured in flame proof trunking but lord knows when or if this would filter through to the Regs. There was a photo of the cables and the blackened shell of the flats ( but can't find it) and it wasn't difficult to see that this would be a problem in all that smoke and heat. At least if they are secured with something flame proof they would at least stay up and out of the way.

Philpot

 

[Richard Burns]

To keep cable off the grid, you could use these types of clips.

I like them, hadn't seen them before; looks very easy to use, I must have misunderstood!

 

[tigerpaul]

There was recently an inquest into the tragic death of two fire fighters in Shirley Towers Southampton. One of the contributing factors was cables hanging down from a suspended ceiling after it collapsed. There were calls for the cables to be secured in flame proof trunking but lord knows when or if this would filter through to the Regs. There was a photo of the cables and the blackened shell of the flats ( but can't find it) and it wasn't difficult to see that this would be a problem in all that smoke and heat. At least if they are secured with something flame proof they would at least stay up and out of the way.

Philpot

Damn right,
Who'd want to be a firefighter walking into a dense jungle of burning cable?

It has been common practice for years now to secure cables onto trays/baskets with metal cable ties as well as the normal plastic ones. This is to ensure they dont all come cascading down when the heat melts the plastic cable ties.
Also all light fittings should be secured to the ceiling with jack chains or gripple wire, so they dont fall down also when the ceiling grid distorts due to the heat generated in a fire.
For these reasons, I would say, cables should be secured to the slab above the ceiling somehow, be it in containment or all round band, as the above have suggested.