Idea bounce - clipping many cables to joist without nails

Nov 29, 2014 16 Replies

Lighting wiring next spring - will have *many* cables running in bundles to switch drops and the like - eg bundles of 4 will be quite common.



Some good cable runs might be between wood with 4" gap, so no space to swing a hammer.



And I'm trying to avoid too much hammering for the ceilings sake... And yes, supporting the cables would be preferred as there are a multitude of sharp protrusions like broken off rusty nails and miss applied plasterboard nails everywhere...


So - ideas please :) Something involving screws as I have a right angled power driver adaptor for tight spaces...


Trunking is an obvious, if expensive and a bit OTT option.



Another - tie wrap base and tie wrap the cables?


22mm plumbing clip (the sort that clip closed but can be pinged open?


To me, the plumbing clip seems a possibly nice idea as the clip and be opened to add the next cable easily. But have I overlooked any snags with this?


Yes

Drill (say) some 1/8 inch holes in adjacent joists and thread a bit of stiff gardening wire through them, for the cables to rest (or hang) on.

Don't "bundle" ring mains together too tight, so avoid local heating.

Thank you :)

Indeed - although two legs of the same circuit won't suffer as both cables can never be fully loaded simultaneously.

But it's not a problem as my rings are already in (and clipped conventionally). It's merely the lighting cables left (mostly) as there are many many cables going in.

Around the perimeter is basket tray - the power circuits are laid out spaced, but the lighting cables will be bundled to one side. I've estimated that for a 6A lighting circuit with star wiring from a group of junction boxes (in a convenient location) that it be roughly equivalent to 3-4 grouped cables at worst (there may be 20 cables but each one is carrying a fraction of the total circuit design load).

a) Main power in b) Switch drops c) Load drop d) Odd 2 way circuit so 2nd switch drop.

That's not going to be a problem with 1.5mm2 T+E

lengths of guttering for the cable to rest in?

Owain

Hook & loop 'velcro' cable ties/hangers?

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Jim K

Specifically I was thinking about these:

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I cannot see any snags - bearing area is about the same as a T+E clip, no sharp edges, and the screw head is actually recessed.

The only gotcha I can see is that as the cable will likely be sitting on the flat rather than on edge, it might be prudent to reduce the clip spacing to maintain support - but as one clip is taking the place of several nailed clips that's no big loss.

Anything I might have missed?

Well I'm sure there are snags as far as legally configured systems are concerned, but I've done it in the past with cable ties and really anything that can be used to hold wires off of joists. No I don't have rats or mice.

Brian

If you use three terminal (loop in/loopout ceiling rose), system there will be no neccessity to have hugh bunches of cables. You will only need twin and earth (brown/blue) and twin and earth (brown/brown). Plus three core and earth between any two way switches. Just use tower clips, the nails are very sharp and knock in easily. No danger of damage to the ceiling.

The only bunches will be were there are multi gang switches. (ie running down the wall. Best done in plastic conduit where it runs down the wall.)

I have put in standard cable clips using a wide opening plumbing wrench to span the sides of the joist and squeeze the nail in. Actually, it's probably easier than hammering them in even if you do have good access to do so.

I found when doing square twist nails into joist hangers (probably similar in size to a largish cable clip nail), that you could push them in using a pry bar and a block of wood against the adjacent joist to act as a base / fulcrum when there was not enough hammer space. (although the side of a hammer can also drive a nail in a narrow space)

If screwed or pinned.

I often use a stable gun with long ish staples to straddle a large releasable cable tie. You can then hang a bunch of wires safely, and retro fit more later.

I like that idea - never thought of a staple gun.

You mean one that puts big fat "U" staples in? Or just a heavy version of what teacher used on the notice boards?

The latter... I have a swingline one that can take staples which have upto 14mm of pin depth to them (the normal cm or so wide). Its quite handy for attaching cable ties to the backs of desk modesty panels etc.

a bit like :

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using

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Not sure if it helps with any thoughts ... in my loft space I run 4 lengths of plastic guttering ... 2 parallel runs front 2 at back .... and that allowed me to simply lay the cables in .... VIDEO/DATA then kept separate form mains in each 'run'

Got the guttering for nothing local BM had plenty of grubby, scratched .. old stock, they were glad to get rid of it for free.

Brian Gaff submitted this idea :

Short bits of T&E, doubled over to make a loop, with a nail or screw through it to form a hanger, is common practice.

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