Mounting lights on trunking

What makes you think that it may not be?

I wasn’t sure or not. As I said I hadn’t used this method before and was wondering if it was common practice

Normally done using 2 x 2 trunking, not sure if you will be able to get the brackets for 3 x 3, might have to knock something up, or is the trunking lid side up?

It would be fairly easily done with two dia 20 brass bushes through the bottom of the trunking and into the fitting its self -one at either end of the fitting. (One brass bush is just there to hold the fitting up though not for cable access/egress) -  assuming that the trunking is indoors and the IP rating is not that important. This will allow the cables to get in and hold the fitting up onto the trunking. Easy job. Put the sharp part of the bush and the lock ring inside the fitting and leave the nut part of the bush in the trunking so any future cable pulls in the trunking flow freely over the bush with no sharp edges in the trunking. 


Kind Regards


Tatty

The fittings I was going to use have two metal clips that fix to whatever surface you are attaching them to and then the fitting ‘clips’ onto these clips so it doesn’t look like I can use the standard bush and lock ring setup as the fittings are effectively ‘held of’ the surface bu the clips. I might have to come out if the trunking with flexible conduit and enter the fitting at one end. My original query was whether fittings should be mounted on trunking at all but your responses have indicated that they can. Thanks

I gather that you propose to fit what are described as 'Anti-Corrosive' led battens which, to maintain their IP rating, should not be drilled, but instead be mounted using the supplied stainless steel clips which you affix to the ceiling first?

I have seen anti corrosives riddled with M20 holes for cable entry into the tops and which have resulted in the housings becoming cracked wide open due to the weight of the control gear inside. LED battens are not as heavy I know but.......

Anyway, mounting onto trunking? Is the trunking mounted on the ceiling with it's bottom side affixed directly to the ceiling? If so, it sounds as if you are proposing to fix your lights to the trunking lid which would be facing downwards towards the floor - not a great idea.

Better to come from the side of the trunking with a bit of conduit, or a coupler, bush and locknut.

I can't see anyone thanking you for having to remove the light fittings each time they need to access the inside of the trunking to get more cables or whatever in.

Hi 

Just to be clear, the trunking is suspended on unistrut with the lid facing up. It isn’t screwed to the ceiling with the lid facing down. I propose to fix the lights to the underside of the trunking using the supplied clips, not bushes and lock rings.

Some of these IP65 anti corrosive things come with a variety of extras for differing application. The most helpful ones come with a pair of hook/eyelet things that attach to the top surface. Usually the couple of M4 bolts/screws come with a steel washer and a plastic, neoprene type gasket. This mitigates the hole "opening up" and cracking as the weight is spread, though the LED ones are very lightweight anyhow. IP65 is then maintained. Usually a IP65 20mm stuffing gland is supplied for one of the ends. So you have power trunking rather than lighting trunking [ as your lid is up ], so you need your own pair of "hooks" on the bottom face of the trunking, or you can use hammer on type hangers say off any angled unistrut or any available purling, if they exist. Appropriate length of chain and a way into the trunking for the flex to the light. That could be a Terminal Box on the bottom of the trunking with a stuffing gland [ compression gland] in the thread. There would be nothing wrong with using a nylon 20mm stuffing gland, instead, straight into trunking unless someone on-site is going to play "consultants inquisition". That nylon gland has added benefit of no sharp edges into the trunking.


Those "springy clip" things are ok, but do not give a lot of confidence. A good tug or twist and they fail, though if there is a tight stuffing gland and flex at least it will stop it falling totally out of the sky!

When ever I fit a fitting like this up on trunking - I'd always use a round lock nut onto the dia 20mm bush to secure the bush to the trunking and then install another lock nut in the fitting; the first lock nut gives it a little spacer between the fitting and the trunking. Less fitting plastic cracking etc that way. 


As others have said - there are plenty of other ways to do the job, but certainly you can hang lights from trunking. 


A 4mm brass screw and nut (the screw- as used for a metal conduit box lid) through the trunking bottom with the head of the screw in the trunking, would secure the flimsy clippy thingy that the fitting can hang off of.

I don't like the flimsy clippy thingy though to hang fittings from but it does provide a fast install method on brick walls or concrete ceilings. 

The hooks would allow you to suspend the fittings lower down........if necessary. Id use jack chain though between the hook and the fitting. 

This picture was taken from the internet to give you the idea - you can get a whole flat plate with a hook on it that'll fit onto the conduit box.

Some of the designs of spring clip are a bit hopeless on a non-flat surface *- I have seen some "value"  trunking that was a bit bendy -- if so you may want something to stiffen the trunking a bit  where the screws go in for the clips, or even a bit of unistrut as an interposer (having fitted the lamp to unistrut, use unistrut to attach to what ever you like really, if things do not line up neatly otherwise). You will need some sort of stuffing gland as well for the cable, but I'm sure you know that.

Those hooks are for jack chains, and while you could do that, short lengths look odd.


(* the IK test for the clips being the Scouts and a football. The whole lot falls out of the clips and dangles sadly by the wires if the clip is anything other than very firm indeed.)