finding the other end of a wire


Old 02-18-13, 07:31 AM
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Join Date: Nov 2012
Location: USA
Posts: 4
finding the other end of a wire

Is there an easy way to find out what wire in one room leads to what wre in another room? What I am trying to do is work on my networked smoke detectors. The builder wired 7 smoke detectors in my house. They are powered by the house electrical system, and are also supposed to be networked, so that if the alarm in the basement goes off, the one in the bedroom will also go off for example. This is done with a red wire supposedly running from one detector to the next in a chain. However although each detector seems to work fine on its own, they are not 'communicating'. They are all new, and all the same detector. So I was thinking of trying to check each of the red wires between each of the detectors for continuity to see if I can find a problem. So I would like to be able to clamp something on the red wire in one room, and then go into nother room to see if that is the other end of the wire and if it is continuous. How can I do this? I have a multimeter, but I can't get the two ens of the wire close enough to put one lead on each end.

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Old 02-18-13, 07:49 AM
Join Date: Jan 2013
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Buy 25-30', or whatever length that you think you might need, of stranded wire?
Old 02-18-13, 08:06 AM
ray2047's Avatar
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I just use an extension cord. Wrap one wire around the ground prong, go to the next room and test each wire to the ground slot for continuity.

Variation use three prong to two prong adapter with a ground pigtail. Then you can just connect to the pigtail instead of wrapping the wire around the ground prong.
Old 02-18-13, 10:08 AM
PJmax's Avatar
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It would be hard to believe there is a problem with the wiring between ALL the units.

One of those smoke detectors must be activated for a certain amount of time to notify the others to signal. Did you try holding the button in for up to 30 seconds ?
Old 02-18-13, 01:27 PM
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A fox and hound toner might be a better option.

I have a hard time believing someone mis-wired all 7 alarms. You should be able to check the connections just by removing the alarms from the mounting rings.

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