Finally getting around to installing an alarm on a prewired house I moved into a few years ago. Long story short, I'm down to a single wiring/sensor problem and there is no continuity (confirmed with DMM and probe/continuity tester). The prewire install was lazy (pigtails connected by twisting and taping, mounting tape directly on dirty surfaces, etc.). Now, I've got a single home run of about 25 ft between a window and the panel, but am unsure of the least invasive way to correct the problem. I'm tempted to tie a new run of wire to one end and yank on the other end to try to pop any staples in-between and pull the whole thing through, but I worry that it will just snap somewhere in the middle and I'll be the worse off for it. Any recommendations on how to fix this? Thanks!
continuity & repair recommendations
- Thread starter dougri
- Start date
Not sure if that is where the problem is... there is about 12" of slack in the line at the window, but no apparent damage (I've already pulled the reed switch and tested that separately). I'm not sure how I would pinpoint where the break is without cutting into the wall, but If I had to place a bet on the location, I'd guess the curtain rod above the window. After a bit closer inspection of the distances involved, I estimate it is under 20ft of wire, but with at least two 90-degree turns and who knows how many staples. Keep the ideas coming, though... something is sure to be better than the crazy things going through my head 
Tried that, but can't note any distinct change in volume of the tone in the wall near the switch location. I can absolutely the tone and trace the wire, but cannot hear a change in the tone that would indicate a break. Is that normal? Continuity fails, DMM resistance shows open circuit as well (I've tied the ends together), but I can still trace it by tone???
Neurorad
Senior Member
I'd probably punch into the wall at the curtain rod bracket, and attempt surgery there. But, then you're stuck with a connection that will be drywalled over. Can you make a hole there, splice, and cover with a blank plate that will be hidden by curtain?
Any possibility of running a new cable? Basement/crawl below, attic above?
Wireless is, of course, a fall-back.
Any possibility of running a new cable? Basement/crawl below, attic above?
Wireless is, of course, a fall-back.
Pulling on the wire is not going to work, especially if it's stapled with anything but a loose romex staple or drive ring.
Short of having a TDM and knowing the route of the cabling....take a toner and tie on one end, short the other end....where you get tone, louder than the bleed through, is where the open should be. It'll take a little skill, but that's the way I've done it before, which should work unless you have a ground fault.
Short of having a TDM and knowing the route of the cabling....take a toner and tie on one end, short the other end....where you get tone, louder than the bleed through, is where the open should be. It'll take a little skill, but that's the way I've done it before, which should work unless you have a ground fault.
I have used an oscilloscope and a square wave signal generator as a TDR. You can see the time it takes for the edge to travel down the wire and reflect from the short or break. If you have a good idea of the route this works pretty well to locate the problem. Hard to get distance if the problem is very close to the start but otherwise works well.
tmbrown97
Senior Member
Yeah - if you're doing your own cabling it would be good to own a good tester; I haven't used it, but that $85 monoprice ethernet tester says it has TDR - I would pull the contact and run the TDR at both ends to get the distance away then start at the short end with a tracer and see if you can locate it.
I single drywall patch/repair will cost a fraction of putting in what's needed to support wireless.
And to echo everyone else - pulling the wire just won't work - it'll break probably within 3' of where you start pulling and you'll now have no wire. Those wires have a pretty low breaking point so unless it was tacked up with the stapler off your desk, that won't accomplish anything good.
I single drywall patch/repair will cost a fraction of putting in what's needed to support wireless.
And to echo everyone else - pulling the wire just won't work - it'll break probably within 3' of where you start pulling and you'll now have no wire. Those wires have a pretty low breaking point so unless it was tacked up with the stapler off your desk, that won't accomplish anything good.
Problem solved. Great ideas guys... hopefully I won't need any new equipment. I had tried newalarm and DEL's suggestion of toning the line previously, as I stated earlier, but with no luck. Then I decided on a whim to tone it from the other end since (the contact end) to see if it made a difference. Sure enough, a distinct drop in volume was noted in the wall adjacent to the window, a few inches below a drapery holdback. So, cut a hole in the wall to investigate and the fault was immediately obvious. The prewire installer had severed a conductor with a staple and apparently never tested for continuity (or did not do so until after the drywall was up and decided to wait and see if they got the work to install the alarm before fixing the issue). After this problem, five faulty reed switches of 29, contacts dislodging due to application over a dirty surface, and lazy wire connections, I'm starting to understand why a few neighbors had numerous alarm issues the first year after construction. And to think I was about to hire them to finish the job and only didn't because they failed to get back to me with a quote (maybe they knew something they were not letting on to... a former, incompetent employee perhaps?).
tmbrown97
Senior Member
Yeah - I'm in the Sac area, but I shopped alarm companies a few years ago - and I was underwhelmed. I was just seeking to avoid going in the attic - I can do my own hookups. In the end, I had my brother-in-law do some of it, before he mis-stepped and fell through my ceiling (and didn't enter an attic for 4 years due to the trauma) - and hired an alarm installer who was very short on personality... but I got it done. In this house, I flew a friend up and we knocked it out over a couple days.
Sounds like a crappy installer - glad you got it worked out!
Sounds like a crappy installer - glad you got it worked out!
It is the problem with contractors who don't end up finishing the work. They often don't care because once they are gone, it is no longer their problem. If they know that they are going to do the final install, they will be much more careful.
Sad thing is, they guy probably saw the staple and damaged wire, and walked away.
I did all my wiring myself and was nervous when they put up drywall, but so far have not had any issues. I was REALLY careful to keep all wires away from line voltage and from drywall screws/nails. Only mistake was in layout, or running 2 wire, were i could have used 4, etc... Novice stuff
Glad you got it resolved. Most problems can be fixed by carefully thinking through, and performing tests.
Sad thing is, they guy probably saw the staple and damaged wire, and walked away.
I did all my wiring myself and was nervous when they put up drywall, but so far have not had any issues. I was REALLY careful to keep all wires away from line voltage and from drywall screws/nails. Only mistake was in layout, or running 2 wire, were i could have used 4, etc... Novice stuff
Glad you got it resolved. Most problems can be fixed by carefully thinking through, and performing tests.
