Advice please, feeding a wire down inside a wall

Forums › Home Workshop DIY › Advice please, feeding a wire down inside a wall

colinuu

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#279770 7-Nov-2020 00:08

I'm trying to feed a wire down inside a wall from the roof space. Holes exist in the dwangs and top plate, but due to a stuff up the wall was gibbed and finished before putting in a draw string. Holes in the top plate and first dwang line up well enough to get a curtain wire through, but the next one down must be out of line and the curtain wire progress is blocked at that point.

Working space under the roof is very limited, probably too awkward to try drilling down to make a new hole in-line. It might be possible to drill up from under the house but we would prefer to avoid it if possible. Any tips or ideas from you full time sparkies how to deal with this?

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Hammered
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#2599335 7-Nov-2020 00:25

Not curtain wire, you'll need something like a decent single core copper that can be shaped/curved and it'll hold the shape (you may get away with as wire coat hanger, at a pinch, if you have no copper wire). Also in some cases a string with a small weight on the end. Or a combined use of both, when it comes to fishing the string out at the bottom if the holes aren't perfectly aligned. Add in some practice, and eventually it's just like fishing. Except it's in cramped, tight places that are often rather hot at this time of year.

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DarthKermit

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#2599339 7-Nov-2020 02:16

The best way I've found, is to attach a length of light chain on to a string and drop it down the hole (gently). The chain should snake its way down through the holes and come out at the end.

Bung

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#2599357 7-Nov-2020 07:26

In a wall that wasn't complicated by insulation I managed to get a light pull cord down through misaligned holes in full nogs by sealing a vacuum hose to the switch plate hole. The the air flow was enough to get the cord to move.

Jase2985

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#2599359 7-Nov-2020 07:40

Bung: In a wall that wasn't complicated by insulation I managed to get a light pull cord down through misaligned holes in full nogs by sealing a vacuum hose to the switch plate hole. The the air flow was enough to get the cord to move.

you can help this by putting a small bit of plastic bag on the end of the cord to increase the surface area for suction

Dingbatt

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#2599361 7-Nov-2020 07:50

If cheap options fail and you don’t want to knock a hole in the gib, there is always something like a fibre-optic camera. Mighty-Ape has them for about $60 (from a quick search). It would depend how they can be manoeuvred, the size of the holes and how much they are misaligned.

Edit: The suction idea is genius.

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andrewNZ

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#2599363 7-Nov-2020 07:59

As has been said, a weighted string is the first thing to try.
Either builders line or fairy strong fishing line with chain or other weight on the end.

If that doesn't work, I'd go straight to drill extension bits if you have access to any.

It can also be helpful to drill an extra hole or two in the top plate for shining a torch / looking down.

Another trick that can sometimes work is going up from the bottom through the first bit of frame and catching the weighted string being dropped down.
A magnet on the end of a goat hanger can work to catch chain on a string.

Your phone cameras are a good tool for looking in walls too.

Danite

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#2599365 7-Nov-2020 08:03

Could also try feeding somthing up from the into the cavity above the first dwang and then hook it from the top.

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eracode

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#2599375 7-Nov-2020 08:29

Bung: In a wall that wasn't complicated by insulation I managed to get a light pull cord down through misaligned holes in full nogs by sealing a vacuum hose to the switch plate hole. The the air flow was enough to get the cord to move.

I have had an OCD hobby of hiding speaker and AV cables inside walls, floors and ceilings for literally 50+ years and consider myself pretty good at it - but I’ve never heard or thought of this brilliant trick. Love it. Thanks.

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colinuu

246 posts

Master Geek

#2599376 7-Nov-2020 08:29

Many thanks for the suggestions. A small round fishing sinker on the end of a light weight string sounds like a good place to start. Cheers all.

SATTV

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#2599378 7-Nov-2020 08:38

I use the curtain wire personally, but the alarm installer used about 50cm of ( bank pen chain ) and fishing nylon and he was super fast.

With something like this it hopefully will find the misalligned hole, or as someone has said go up and try and hook it from below.

If all else fails i have seen very long and flexible drills for drilling holes in walls, you then use them as a draw wire, probably cost a bit but saves on lots if time.

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eracode

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#2599384 7-Nov-2020 09:00

SATTV:

I use the curtain wire personally, but the alarm installer used about 50cm of ( bank pen chain ) and fishing nylon and he was super fast.

John

Might need to visit several branches to get enough chain to do the job. 😀

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colinuu

246 posts

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#2600705 9-Nov-2020 21:22

Phase 2:

So it turns out that the real reason for the problem is not because the holes are mis-aligned, but the result of the builder inserting some left over insulation batts into the wall. (Discovered today with the aid of a fibre optic inspection camera.) Not sure why he did that - it's a wall between bathroom and laundry.

Now to figure out a way to push past the batts and still find the hole at the bottom...

Delphinus

611 posts

Ultimate Geek

#2600728 9-Nov-2020 22:01

Can you poke down some pipe like electrical conduit, that is small enough to fit in the holes, then would allow you to feed your cable down the middle of this conduit?

Brunzy

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#2600818 10-Nov-2020 09:28

Fibre glass rods

wellygary

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#2600848 10-Nov-2020 09:54

colinuu:

Phase 2:

So it turns out that the real reason for the problem is not because the holes are mis-aligned, but the result of the builder inserting some left over insulation batts into the wall. (Discovered today with the aid of a fibre optic inspection camera.) Not sure why he did that - it's a wall between bathroom and laundry.

Now to figure out a way to push past the batts and still find the hole at the bottom...

How many dwangs are a problem?.. If its just one, then you have two choices,

1) Try like sin to try and rod past/through the insulation - less likely to succeed and could take a while

2) Cut a hole in the gib ,- you can either then repatch the gib , sand and paint, or just put a blank switch plate over it,

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