Threading a cable in ceiling void from below

Mar 25, 2017 36 Replies

It looks as though I'm going to have to thread a thin, so very flexible, cable into the ceiling void from below and then out again a couple of metres further across. I've used a straightened coat hanger in similar circumstances before but the current stock won't straighten to the required distance.



I can't get at it from above, but at least the joists run in the right direction for me.



So what's the best way to do it?


feed an extending metal tape measure through the space at the other end, tie on a piece of string and then retract the tape, pulling the string through. Remove string from tape and fix to cable. Then pull string from far end.

Tie a thread to a mouse and coax it across to the other hole with cheese. Tie a string to the thread, pull it through and then the cable.

(Perhaps that's not the *best* way to do it.)

Use a very old and infertile mouse.

The best way is cable rods. Sometimes available at Aldi/Lidl.

If using a metal tape measure be wary of any exposed electrically live things in the void it might touch.

Garden canes might be an option. The flexible-ish lid of mini-trunking can also be useful.

Owain

In case it lays eggs up there.

In message , snipped-for-privacy@gowanhill.com writes

As can that flexible white coated stuff used for hanging net curtains.

another substitute for fish tape is iron wire. But again beware of it touching something live.

NT

Tie a small piece of iron, such as a 1" nail (insulated with tape if necessary), to a thin, strong thread. Push through hole into ceiling space and pull along with a neodymium magnet just under the ceiling. Once the nail appears, pull through and tie the cable to the thread, and pull that through.

For a plasterboard ceiling then magnets ? I've not been following the magnet thread but a while back I bought 2 small (2.2cm long) cylindrical magnets off of eBay for some reason I've long forgotten. Trying them out on top and underneath a 38mm worktop then positioned lengthwise the bottom one easily moves the top one providing the polarity is reversed. The top magnet spins automatically at the start in any case. With a bit of string tied to the top one this should work.

If its lath and plaster then you're buggered as ,as soon as it meets an obstruction equivalent in height to a lath, the top magnet stands up and then does a back somersault despite manipulating the bottom magnet in various ways.

michael adams

...

I have used the top section of an old fishing rod in the past.

Be aware that it might touch a live wire or terminal.

Bill

You could use drain rods, or a garden cane.

Bill

A good friend, a very good electrician, always uses the cover of a smallish trunking for that purpose, e.g.

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Flat, semi-rigid, and non-conductive, and he simply tapes the end of the cable to it.

or something similar:

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via shorter link:

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Top marks for most novel approach so far

I use a length of curtain track, the sort that comes on a roll. It works well for threading down blob fixed plaster board so a ceiling should be easy.

I use one of those flexible drain wire things. Just attach what you want to put thru the void to it, get it to where you want, detach the cable from it and pull the drain thing back again leaving the cable where you want it.

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or

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Solves the possible (but hopefully highly unlikely) metal measuring tape coming in contact with something live. Minimum bend radius somewhere between 6 and 9" before they splinter DAMHIKT...

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