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Hot wire discontinuity between smoke detectors

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Jul 30, 2012, 07:47 PM
georgiboy7
Hot wire discontinuity between smoke detectors
Hey all. I am having trouble with a wire and am at the end of my electrical ability. My house is wired with 7 smoke detectors on a dedicated circuit. Only the first 4 pick AC voltage from the breaker. Through testing and process of elimination, I have found discontinuity on hot wire from #4 and #5. The wires don't appear burned, broken, etc. I have tried wiggling the wire to see if continuity will momentarily come back with no luck. I have also used a stud scanner with AC scan setting to pick up a hot wire in the wall to find where (if any) there is a break.... again no luck. Any other ideas? My next action is to pull the wire and re run a new wire, but wire goes from the top of the 2nd floor to the top of the 3rd floor.... and I don't know how many studs / joists it goes through to get there... I also think that the staples will prevent me from pulling the old wire (the wiring was stapled in another area of the house). Any other thoughts?

How would one run a new wire between a 2nd and 3rd floor place with no attic access?

Thanks for the response.
Jul 31, 2012, 02:51 PM
Re-mdlr
Staples or some fastener is required. It is annoying when trying to add more wire. Maybe cut away sheetrock, add new wire.

But first, have you removed the wire nuts to check the connections? I'd pull on each individual wire first to see if maybe one is loose. If that didn't show me something, then I'd remove the caps to make sure connections are proper. Even a pro electrician can have a slip up. If all 7 defectors, oops, detectors are on the same circuit, and they should be, then you should have power going all the way up to the last one in line. Also, verify all interconnect wires are hooked up properly by color codes. They are interconnected I assume, but maybe not depending on when they were installed originally.

I worked on a detector two weeks ago that when I pulled one of the sets of wires out to check it, one of the wires popped out of the cap. Thats not suppose to happen, but it does.

This message has been edited. Last edited by: Re-mdlr,
Aug 08, 2012, 07:08 PM
swschrad
it is axiomatic in the books that when you connect wires with a wire nut, you first strip them down, then twist them together with a lineman's pliers so they are mechanically secure (including twisting until there are 2 to 3 twists in the insulated wire beyond where you stripped.)

the issue comes when you then add the thin, stranded wire from a fixture or a detector cable.

and those are the two things to check after you pull the breaker, insure there is no power with a beepy tester, and open the wire nuts.


sig: if this is a new economy, how come they still want my old-fashioned money?
Aug 09, 2012, 08:58 AM
Re-mdlr
quote:
Originally posted by Re-mdlr:
I worked on a detector two weeks ago that when I pulled one of the sets of wires out to check it, one of the wires popped out of the cap. Thats not suppose to happen, but it does.


It wasn't one of the thin wires that popped out. Thats why I like to grab them and check them for a loose wire before I take a cap off. I like knowing I found the problem, I fixed the problem, won't return.

It may be axiomatic in books, but I live in the real world. And wires are not always twisted together, even in new houses.
Aug 09, 2012, 03:13 PM
swschrad
but you better believe when I open something up, I twist 'em down so I won't have to go chasing issues again.

we used to have a bunch of blinking lights in the house. first step before we moved in, I shotgunned all the loose outlets, replaced 'em all, every one, and all the creepy light switches I found. all new switches as we remodelled. and every wire nut I came across, I opened, cleaned off the spray paint, stripped back to good wire if there were too many nicks and kinks, and twisted before nutting.

only a couple issues left to find when I get time.

This message has been edited. Last edited by: swschrad,


sig: if this is a new economy, how come they still want my old-fashioned money?